Determination of90Sr in environmental samples with resonance ionization spectroscopy in collinear geometry

1994

A new, fast technique for trace analysis of the radioactive isotopes89Sr and90Sr in environmental samples has been developed. Conventional mass separation is combined with resonance ionization spectroscopy in collinear geometry, which provides high selectivity and sensitivity. In addition, a chemical separation procedure for sample preparation has been developed. The described technique was used to determine the90Sr content in ≈ 870 m3 air samples collected near Munich during and shortly after the Chernobyl reactor accident in April 1986. The content of90Sr was measured to be 1.4 mBq per m3, corresponding to 1.6 × 109 atoms of90Sr per sample. This value is in good agreement with the results…

Magnetized boxes for housing polarized spins in homogeneous fields

2010

Abstract We present novel types of permanently magnetized as well as current powered boxes built from soft-ferromagnetic materials. They provide shielded magnetic fields which are homogeneous within a large fraction of the enclosed volume, thus minimizing size, weight, and costs. For the permanently magnetized solutions, homogenization is achieved either by an optimized distribution of the permanent field sources or by jacketing the field with a soft-ferromagnetic cylindrical shell which is magnetized in parallel to the enclosed field. The latter principle may be applied up to fields of about 0.1 T. With fields of about 1 mT, such boxes are being used for shipping spin-polarized 3 He worldw…

Fast-beam laser spectroscopy of neutron-rich barium isotopes

1981

Einführung in Thema und Erscheinungswelt der Physik

1998

Die Einfuhrung in ein neues Wissensgebiet sollte damit beginnen, seinen Rahmen abzustecken und seine Ziele und Methoden zu definieren. Obwohl dieses Buch nur den bescheidenen Anspruch eines Repetitoriums hat, wollen wir uns dieser Aufgabe nicht ganz entziehen und ihr dieses erste Kapitel widmen.

Nuclear hyperpolarization of 3He by magnetized plasmas

2018

International audience; We describe a method, referred to as PAMP (polarization of atoms in a magnetized plasma), that allowshyperpolarization of 3He nuclear spins at high magnetic field solely by excitation of a rf gas discharge.A magnetized plasma is obtained when the mean free path of the free electrons is much larger than theirgyration radius in the rf gas discharge. Investigations of PAMP are carried out in the 1–15-mbar pressure rangewith rf excitation around 100 MHz. Quantitative NMR measurements at 4.7 T and room temperature showthat, for different cell sizes and gas densities, 3He nuclear polarizations in the 1 to 9% range are achieved(i.e., larger than the Boltzmann equilibrium sp…

Elastische Kräfte und deren molekulare Grundlagen

1998

In den folgenden Kap. 8 bis 10 diskutieren wir physikalische Eigenschaften der verschiedenen Aggregatzustande der Materie, also von festen Korpern, Flussigkeiten und Gasen, soweit diese Eigenschaften mechanischer Natur sind und nicht zur Warmelehre gehoren. Hierzu zahlt vor allem, wie sie auf ausere Krafte oder Drucke durch Verformung reagieren. Wir werden zunachst die makroskopischen, elastischen Verformungen fester Korper behandeln und dann ein mikroskopisches Modell der Krafte zwisch en einzelnen Atomen und Molekulen einfuhren. Es erklart den Zusammenhalt der Atome im Molekul und in kondensierter Materie auf der Basis eines bestimmten, interatomaren Potentials. Es beschreibt viele Materi…

Relativistic J-dependence of the isotope shift in the 6s-6p doublet of Ba II

1984

The collinear laser-ion beam technique has been used to measure the isotope shift and hyperfine structure in the 6s-6p doublet (4,934A, 4,554A) of Ba II for all seven stable isotopes. The influence of the excited2P1/2 and2P3/2 states on the field shift leads to a difference of 2.5(3)% in the electronicF factors. The specific mass shifts differ by {A′-A} 2.2(3) MHz which corresponds to about 12% of the normal mass shift.

From radop to laser spectroscopy and back

1985

The paper reviews some techniques in optical spectroscopy of short-lived nuclei, their results regarding nuclear moments and isotopic shift, and their relation to the work of Professor K. Sugimoto.

From lamps to lasers—Optical spectroscopy of radioactive atoms

1993

Stoffe in verschiedenen Aggregatzuständen

1998

Wir wollen in diesem Kapitel die Vorstellung von Atomen und Molekulen als „harten Billardkugeln oder Hanteln“, die dem idealen Gas zugrunde liegt, verlassen. Es gilt jetzt, die Bindungskrafte zwischen ihnen zu berucksichtigen. Bei entsprechend niedrigen Temperaturen gewinnen sie die Oberhand und fuhren die Kondensation des Gases zur Flussigkeit und schlieslich die Erstarrung zum Festkorper herbei. Bezuglich dieser Bindungskrafte werden wir uns wieder an dem schon mehrfach benutzten Lenard-Jones-Potential (8.22) orientieren $$V(r) = \sigma \left( {\frac{{r_0^6}}{{{r^{12}}}} - \frac{2}{{{r^6}}}} \right).$$

Evaluation of the magnetic moments of radium isotopes

1990

Using the relativistic linked cluster many-body perturbation procedure we have obtained the hyperfine field at the nucleus of the Ra+ ion in the2S1/2 ground state. There is good agreement between the calculated magnetic moment of213Ra and the results of a recent Zeeman measurement by the collinear laser beam technique. Detailed comparison is carried out between our result and earlier ones.

Interdisciplinary experiments with polarized 3He

1998

Abstract Optical pumping of metastable 3 He atoms is a very efficient method to produce large quantities of nuclear spin-polarized 3 He. Recent developments in mechanical compression of the gas, its storage and transport allow for its flexible use in different fields of physics and applied science. Among these are (1) scattering experiments of polarized beams from polarized 3 He-targets, (2) 3 He as neutron spin filter to polarize neutron beams at research reactors, and (3) polarized 3 He gas inhaled into the lungs to perform magnetic resonance imaging. The paper discusses the different topics along with results obtained in a first round of experiments.

Natur und Eigenschaften des Lichts, seine Wechselwirkung mit Materie

1998

Wir hatten in Kap. 26 die elektromagnetischen Wellen kennengelernt, die ihren Ursprung in oszillierenden Ladungen und Stromen haben. Mit hochfrequenztechnischen Mitteln hatten wir koharente, monochromatische Mikrowellen mit Wellenlangen im Bereich von Zentimetern erzeugt und damit alle typischen Wellenerscheinungen zeigen konnen wie Reflexion, Brechung, Beugung etc. Auserdem haben wir die Polarisation elektromagnetischer Wellen demonstriert und daraus ihren transversalen Charakter bewiesen (s. Versuch 26.5).

Quadrupole moments of radium isotopes from the 7p 2 P 3/2 hyperfine structure in Ra II

1988

The hyperfine structure and isotope shift of221–226Ra and212,214Ra have been measured in the ionic (Ra II) transition 7s 2 S 1/2–7p 2 P 3/2 (λ=381.4 nm). The method of on-line collinear fast-beam laser spectroscopy has been applied using frequency-doubling of cw dye laser radiation in an external ring cavity. The magnetic hyperfine fields are compared with semi-empirical and ab initio calculations. The analysis of the quadrupole splitting by the same method yields the following, improved values of spectroscopic quadrupole moments:Q s (221Ra)=1.978(7)b,Q s (223Ra)=1.254(3)b and the reanalyzed valuesQ s (209Ra)=0.40(2)b,Q s (211Ra)=0.48(2)b,Q s (227Ra)=1.58(3)b,Q s (229Ra)=3.09(4)b with an ad…

Strömende Flüssigkeiten und Gase

1998

Das Interesse der Physik an Stromungen von deformierbaren Medien, namlich Flussigkeiten und Gasen, konzentriert sich in erster Linie darauf, mechanische Bewegungsgesetze hierfur zu finden. Mit dieser Aufgabe hatten wir uns in fruheren Kapiteln bereits fur Massenpunkte und starre Korper auseinandergesetzt. Das hier zur Debatte stehende Feld, die sogenannte Hydrodynamik ist freilich sehr viel komplexer. Dennoch konnen wir mit elementaren Mitteln ein grundlegendes Gesetz uber das Druck- und Geschwindigkeitsfeld gewinnen, mit dem sich viele wichtige Stromungsphanomene erklaren lassen. Auch konnen wir etwas Quantitatives uber innere Reibungen von Stromungen lernen. Bei dem vielseitigen und kompl…

Nuclear orientation of radon isotopes by spin exchange optical pumping

1988

This paper reports the first demonstration of nuclear orientation of radon atoms. The method employed was spin exchange with potassium atoms polarized by optical pumping. The radon isotopes were produced at the ISOLDE isotope separator of CERN. The nuclear alignment of /sup 209/Rn and /sup 223/Rn has been measured by observation of ..gamma..-ray anisotropies and the magnetic dipole moment for /sup 209/Rn has been measured by the nuclear-magnetic-resonance method to be chemically bond..mu..chemically bond = 0.838 81(39)..mu../sub N/.

An on-line mass separator for fission-produced alkali isotopes

1980

Abstract The design of an on-line mass separator installed at the TRIGA reactor in Mainz is described and its performance discussed. A tungsten oven, filled with about 2 g of 235U embedded in graphite, is exposed to a flux of 1.7 × 1011 thermal neutrons (s− cm−2) near the reactor core. After diffusion out of the graphite the fission-produced alkali isotopes are surface-ionized and electromagnetically mass-separated, the resolving power being about 750. Losses during the diffusion out of the target material are discussed. Due to these losses the maximum separator efficiency is about 5%, corresponding to a source strength of about 109 particles s−1 for the most abundant isotopes. The heaviest…

Imaging of the lungs using 3he MRI: Preliminary clinical experience in 18 patients with and without lung disease

1997

The purpose of this study was to describe the 3He MRI findings of normal pulmonary ventilation in healthy volunteers and to evaluate abnormalities in patients with different lung diseases. Hyperpolarized 3He gas (300 ml, 3 x 10(5) Pa, polarized to 35-45% by optical pumping, provided in special glass cells) was inhaled by 8 healthy volunteers and 10 patients with different lung diseases. Imaging was performed with a three-dimensional fast low-angle shot (FLASH) sequence (TR = 11.8 msec; TE = 5 msec; transmitter amplitude, 5-8 V; corresponding flip angle, < 5 degrees) in a single breath-hold (22-42 seconds). Clinical and radiological examinations were available for correlation. The studies we…

Nuclear magnetic resonance imaging of airways in humans with use of hyperpolarized3He

1996

The nuclear spin polarization of noble gases can be enhanced strongly by laser optical pumping followed by electron-nuclear polarization transfer. Direct optical pumping of metastable 3He atoms has been shown to produce enormous polarization on the order of 0.4-0.6. This is about 105 times larger than the polarization of water protons at thermal equilibrium used in conventional MRI. We demonstrate that hyperpolarized 3 He gas can be applied to nuclear magnetic resonance imaging of organs with air-filled spaces in humans. In vivo 3 He MR experiments were performed in a whole-body MR scanner with a superconducting magnet ramped down to 0.8 T. Anatomical details of the upper respiratory tract …

Realization of administration unit for3He with gas recycling

2011

Hyperpolarized (HP) noble gases (3He,129Xe) are used for MR-imaging of the lung. In the majority of case the HP gas is filled in Tedlarbags and directly inhaled by the patients. Starting from an earlier pilot device, an administration unit was built respectively to the Medical Devices Law to administer patients HP noble gas boli in defined quantities and at a predefined time during inspiration with high reproducibility and reliability without reducing MR-quality. The patient's airflows are monitored and recorded. It is possible to use gas admixtures, measure the polarization on-line and collect the exhaled gas for later recycling. The first images with healthy volunteers were taken with thi…

Collinear Laser Spectroscopy on Fast Atomic Beams

1978

In collinear geometry we have observed laser-excited, narrow resonances in fast beams of Na and Cs atoms obtained from ion beams by charge transfer collisions. Being very sensitive, the method is suited for measuring isotope shifts and hyperfine structure of isotopes far from stability provided by on-line mass separators. It may be used furthermore to study inelastic charge transfer from the energy-loss spectrum of the Doppler-shifted lines.

Commissioning of the vacuum system of the KATRIN Main Spectrometer

2016

The KATRIN experiment will probe the neutrino mass by measuring the β-electron energy spectrum near the endpoint of tritium β-decay. An integral energy analysis will be performed by an electro-static spectrometer (``Main Spectrometer''), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m[superscript 3], and a complex inner electrode system with about 120 000 individual parts. The strong magnetic field that guides the β-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. A system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter strips ha…

Narrowed optical lines observed in laser method for use with accelerated beams

1978

Trace Analysis of Plutonium and Technetium by Resonance Ionization Mass Spectrometry Using an Atomic Beam and a Laser Ion Source

1990

A method for low level detection of plutonium and technetium is described with a detection limit of less than 107 atoms. Plutonium is a very toxic element due to its radioactive decay as well as its chemical behaviour. It was released to the environment in large amounts during the fifties and sixties of his century, principally by nuclear-weapon tests and some accidents. As a result about 0.4 − 4 mBq per gram 239Pu(T1/2 = 24390 y), corresponding to 4 × 108 − 4 × 109 atoms, can be found in the Northern Hemisphere in soil samples.

Spherical fused silica cells filled with pure helium for nuclear magnetic resonance-magnetometry.

2016

High magnetic fields (> 1 T) are measured by NMR magnetometers with un-rivaled precision if the precessing spin sample provides long coherence times. The longest coherence times are found in diluted ${}^{3}$He samples, which can be hyperpolarized for sufficient signal strength. In order to have minimal influence on the homogeneity and value of the measured magnetic field the optimal container for the ${}^{3}$He should be a perfect sphere. A fused silica sphere with an inner diameter of 8 mm and an outer diameter of 12 mm was made from two hemispheres by diffusion bonding leaving only a small hole for cleaning and evacuation. This hole was closed in vacuum by a CO${}_{2}$ laser and the inner…

3He-MRI-based measurements of intrapulmonarypO2 and its time course during apnea in healthy volunteers: first results, reproducibility, and technical…

2000

We applied a recently developed method of following the time course of the intrapulmonary oxygen partial pressure p(O2)(t) during apnea by (3)He MRI to healthy volunteers. Using two imaging series with different interscan times during two breathholds (double acquisition technique), relaxation of (3)He due to paramagnetic oxygen and depolarization by RF pulses were discriminated. In all four subjects, the temporal evolution of p(O2) was found to be linear, and was described by an initial partial pressure p(0) and a decrease rate R. Also, regional differences of both p(0) and R were observed. A correlation between p(0) and R was apparent. Finally, we discuss limitations of the double acquisit…

A dense polarized 3He target based on compression of optically pumped gas

1992

Abstract 3 He-gas is spin polarized by the method of optical pumping of metastables and metastability exchange in a low pressure gas discharge. At a pressure of p ≈ 1.5 Torr a volume of 1 l is polarized within about 30 s to a degree of 50% with 300 mW of incident light from an argon-ion laser pumped LNA laser, tuned to the λ = 1.083 μm resonance line. The polarized gas is compressed by a Toepler pump into a target cell of 120 cm 3 volume. In a first attempt a steady state polarization of 30% has been achieved in the target at a pressure of 685 Torr. The paper analyses the essential parameters governing this technique and pilotes its experimental realization.

Trace detection of plutonium by three-step photoionization with a laser system pumped by a copper vapor laser

1985

Laser photoionization has been used to detect trace amounts of plutonium. A high sensitivity and selectivity has been achieved by applying three-step excitation and ionization of the plutonium atoms with high pulse-repetition rates and additional mass determination by time-of-flight measurements. A laser system was developed which consists of a copper vapor laser pumping three dye lasers simultaneously. Samples containing between 1010 and 1012 atoms of239Pu on Re filaments were measured yielding strong resonance signals with maximum ion count rates of several kHz at a vanishingly low background. A detection efficiency of 10−7 was determined allowing the detection of about 108 plutonium atom…

Fast, low-level detection of strontium-90 and strontium-89 in environmental samples by collinear resonance ionization spectroscopy

1993

Environmental assessment in the wake of a nuclear accident requires the rapid determination of the radiotoxic isotopes 89Sr and 90Sr. Useful measurements must be able to detect 108 atoms in the presence of about 1018 atoms of the stable, naturally occurring isotopes. This paper describes a new approach to this problem using resonance ionization spectroscopy in collinear geometry, combined with classical mass separation. After collection and chemical separation, the strontium from a sample is surface-ionized and the ions are accelerated to an energy of about 30 keV. Initially, a magnetic mass separator provides an isotopic selectivity of about 106. The ions are then neutralized by charge exc…

Hyperfine structure and isotope shift of the neutron-rich barium isotopes139?146Ba and148Ba

1988

The hyperfme structure and isotope shift in the 6s 2 S 1/2−6p 2P3/2 line of Ba II (455.4 nm) have been measured by collinear fast-beam laser spectroscopy for the neutron-rich isotopes139–146Ba and148Ba. Nuclear moments and mean square charge radii of these isotopes have been recalculated. The isotope shift of the isotope148Ba (T1/2=0.64 s) could be studied for the first time, yieldingδ〈r2〉138,148=1.245(3) fm2.

Isotope shift of182Hg and an update of nuclear moments and charge radii in the isotope range181Hg-206Hg

1986

The technique of collinear fast-beam laser spectroscopy has been used to measure the isotope shifts of the even-even isotopes of Hg (Z=80) in the mass range 182≤A≤198 at the on-line mass separator ISOLDE at CERN. The atomic transition studied (6s 6p 3 P 2- 6s7s 3 S 1,λ=546.1 nm) starts from a metastable state, which is populated in a quasi resonant charge transfer process. The resulting changes in nuclear mean square charge radii show clearly that182Hg follows the trend of the heavier, even, weakly oblate isotopes. Correspondingly the huge odd-even shape staggering in the light Hg isotopes continues and the nuclear shape staggering and shape coexistence persists down to the last isotope inv…

First operation of the KATRIN experiment with tritium

2020

AbstractThe determination of the neutrino mass is one of the major challenges in astroparticle physics today. Direct neutrino mass experiments, based solely on the kinematics of $$\upbeta $$β-decay, provide a largely model-independent probe to the neutrino mass scale. The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to directly measure the effective electron antineutrino mass with a sensitivity of $$0.2\hbox { eV}$$0.2eV ($$90\%$$90% CL). In this work we report on the first operation of KATRIN with tritium which took place in 2018. During this commissioning phase of the tritium circulation system, excellent agreement of the theoretical prediction with the recorded spectra was …

Nuclear ground state properties from optical investigations

1986

Recent progress in on-line techniques of laser spectroscopy applied to nuclei far off stability is reviewed. The results concern nuclear spins, moments and charge radii, determined from hyperfine structure and isotope shift of atomic transitions. Examples of large core polarizations in the Cd-In-Sn region, derived from isotope shifts, and the octupole deformation in the Ra region, derived from ground state spins and magnetic moments, are discussed.

Impuls und Impulserhaltungssatz

1998

Auch im Zentrum dieses Kapitels steht ein Erhaltungssatz. Er bezieht sich auf eine noch zu definierende, kinematische Grose, die wir Impuls nennen. Ahnlich wie die Energie ist der Impuls ein abstrakter Begriff, der rein aus der Physik gewonnen wurde und nicht aus der taglichen Erfahrung. Impuls und Impulserhaltungssatz sind unentbehrlich, um die Bewegung eines Systems von wechselwirkenden Korpern zu studieren, etwa den Stos mehrerer Korper untereinander. Wir beginnen mit der Definition des Impulses fur einen Massenpunkt.

The Q-value of tritium β-decay and the neutrino mass

2006

Abstract The paper discusses the influence of β -endpoint energies and related atomic mass values on the determination of the neutrino mass in present and future β -decay experiments with particular emphasis on the case of tritium decay

Energie und Energiesatz

1998

Wir suchen in den folgenden Kapiteln Erhaltungssatze der Mechanik. Das sind Grosen, die unabhangig von der Zeit oder vom Ort sind.

First measurement of the polarisation transfer on the proton in the reactions $$H(\vec e,e'\vec p)$$ and $$D(\vec e,e'\vec p)$$

1995

The measurement of the polarisation transfer to the proton in the reactions\(H(\vec e,e'\vec p)\) and\(D(\vec e,e'\vec p)\) performed with longitudinally polarised electrons in quasi-free kinematics is presented. The coincidence measurement was executed atQ2≈8fm−2 using the 855 MeV, c.w. beam of the Mainz Microtron MAMI. The recoil polarisation was determined by means of a carbon analyser. The experiment shows that the binding of the nucleon does not modify the polarisationPx of the recoil proton within an error ofΔPx/Px≈10%. The measured polarisation agrees with recent theoretical predictions. Implications for the measurement of the electric form factor of the neutron using the\(D(\vec e,e…

Reduction of stored-particle background by a magnetic pulse method at the KATRIN experiment

2018

Arenz, M., et al. “Reduction of Stored-Particle Background by a Magnetic Pulse Method at the KATRIN Experiment.” The European Physical Journal C, vol. 78, no. 9, Sept. 2018. © 2018 The Authors

A polarized 3He target for the photon beam at MAMI

2011

Abstract A polarized 3 He target has been installed for the first time inside the 4 π Crystal Ball detector at the tagged photon beam of the MAinz MIcrotron (MAMI). It has been demonstrated that the system works reliably and that the polarization losses during handling of the polarized gas are under control. Initial polarization values up to 70% and total relaxation times up to 20 h could be obtained during a first test beam time devoted to the measurement of the double polarized photoabsorption cross-section in the Δ ( 1232 ) baryon resonance region.

Principle and analytical applications of resonance lonization mass spectrometry

1989

Resonance ionization mass spectrometry (RIMS) is a very sensitive analytical technique for the detection of trace elements. This method is based on the excitation and ionization of atoms with resonant laser light followed by mass analysis. It allows element and, in some cases, isotope selective ionization and is applicable to most of the elements of the periodic table. A high selectivity can be achieved by applying three step photoionization of the elements under investigation and an additional mass separation for an unambiguous isotope assignment. An effective facility for resonance ionization mass spectrometry consists of three dye lasers which are pumped by two copper vapor lasers and of…

Trace Analysis of the Radionuclides90Sr and89Sr in Environmental Samples I: Laser Mass Spectrometry

1995

Helium-3-MRT der Lungenventilation: Erste klinische Anwendungen

1997

PURPOSE: of the study is the visualisation of normal pulmonary ventilation in healthy volunteers and the evaluation of abnormalities in patients with different lung diseases using 3He magnetic resonance imaging (3He-MRI). MATERIAL AND METHODS: Hyperpolarized 3He gas (V = 300 ml, p = 3 x 10(5) Pa, polarised to 35-45% by optical pumping, provided in special glass cells) was inhaled by eight healthy volunteers and ten patients with different lung diseases. A 3D FLASH sequence (TR = 11.8 ms; TE = 5 ms; matrix 144 x 256, FOV 350 mm, section thickness 7-10 mm, coronal orientation) was performed in a single breath-hold (22-42 s). Clinical and radiological examinations were available for correlatio…

Realization of a broad band neutron spin filter with compressed, polarized 3He gas

1997

The strongly spin dependent absorption of neutrons in nuclear spin polarized 3He opens the possibility to polarize beams of thermal and epithermal neutrons. An effective 3He neutron spin filter (NSF) requires high 3He nuclear polarization as well as a filter thickness corresponding to a gas amount of the order of 1 barl. We realized such a filter using direct optical pumping of metastable 3He∗ atoms in a 3He plasma at 1 mbar. Metastable exchange scattering transfers the angular momentum to the whole ensemble of 3He atoms. At present 3 × 1018 3He-atoms/s are polarized up to 64%. Subsequent polarization preserving compression by a two stage compressor system enables to prepare NSF cells of ab…

Evaluation of the magnetic moment ofRa213

1991

The hyperfine field at the nucleus of singly ionized radium has been investigated using the relativistic linked-cluster many-body-perturbation-theory procedure, including the effects of distributed charge and magnetization over the nucleus. The total hyperfine field of 1239 T, when combined with the experimentally observed hyperfine constant for $^{213}\mathrm{Ra}^{+}$, yields a nuclear moment of 0.607(12)${\mathrm{\ensuremath{\mu}}}_{\mathit{N}}$, in excellent agreement with the experimentally observed moment of 0.6133(18)${\mathrm{\ensuremath{\mu}}}_{\mathit{N}}$ from Zeeman measurements. Our investigation leads to exchange core-polarization and correlation contributions of 14% and 13%, r…

Nuclear Radii and Moments of Unstable Isotopes

1989

The development of on-line mass separators, which provide long chains of isotopes extending far off stability, immediately raised the question of how to gain access to the basic nuclear ground-state properties of these exotic nuclei—their spins, moments, radii, and masses. In general, the amount of radioactive material produced at these facilities is too small to form beams or targets for any kind of scattering or nuclear-reaction experiment. On the other hand, the traditional spectroscopic methods, namely, atomic, nuclear, and mass spectroscopy, have turned out to be very suitable for this application since they are easily adapted to the special on-line conditions.

Interferenz und Beugung von Licht

1998

Schon in der allgemeinen Wellenlehre hatten wir in Abschn. 12.4 Interferenz und Beugung als wesentliche Merkmale der Wellenausbreitung kennengelernt. Deswegen konnte sich auch Christiaan Huygens Wellenhypothese von der Natur des Lichts erst endgultig durchsetzen, als Thomas Young 150 Jahre spater (um 1800) die ersten Interferenzversuche mit Licht gelangen. Er fuhrte u. a. Versuche mit Spaltblenden durch und konnte die periodischen Helligkeitsmuster hinter den Blenden als Interferenz Huygensscher Elementarwellen (s. Abschn. 12.4) deuten. Auch die Farben dunner Plattchen und die von Newton schon beobachteten Newtonschen Ringe konnte er mit dem von ihm aufgestellten Interferenzprinzip erklaren…

Suppression of Penning discharges between the KATRIN spectrometers

2020

The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective electron (anti)neutrino mass with a sensitivity of $0.2\textrm{ eV/c}^2$ (90$\%$ C.L.) by precisely measuring the endpoint region of the tritium $\beta$-decay spectrum. It uses a tandem of electrostatic spectrometers working as MAC-E (magnetic adiabatic collimation combined with an electrostatic) filters. In the space between the pre-spectrometer and the main spectrometer, an unavoidable Penning trap is created when the superconducting magnet between the two spectrometers, biased at their respective nominal potentials, is energized. The electrons accumulated in this trap can lead to discharges, which create a…

Determination of nuclear spins of short-lived Rb and Cs isotopes by β radiation detected optical pumping

1978

The status of the Mainz neutrino mass experiment

1998

Abstract The present status of the Mainz tritium β decay experiments is given. The very recent improvement of the Mainz setup and the first tritium data are presented.

Determination of nuclear spins and moments in a series of radium isotopes

1983

Abstract The first investigation of hyperfine structure in radium isotopes has enabled the determination of nuclear spins, magnetic dipole and electric quadrupole moments of the isotopes with mass numbers A = 211, 213, 221, 223, 225, 227 and 229. Isotope shifts in the mass range A = 208−232 have also been measured. These studies were carried out using the technique of on-line collinear fast beam laser spectroscopy.

Recycling of 3He from lung magnetic resonance imaging

2011

We have developed the means to recycle 3He exhaled by patients after imaging the lungs using magnetic resonance of hyperpolarized 3He. The exhaled gas is collected in a helium leak proof bag and further compressed into a steel bottle. The collected gas contains about 1–2% of 3He, depending on the amount administered and the number of breaths collected to wash out the 3He gas from the lungs. 3He is separated from the exhaled air using zeolite molecular sieve adsorbent at 77 K followed by a cold head at 8 K. Residual gaseous impurities are finally absorbed by a commercial nonevaporative getter. The recycled 3He gas features high purity, which is required for repolarization by metastability ex…

Quantitative Detection of Strontium-90 and Strontium-89 in Environmental Samples by Laser Mass Spectrometry

1990

Parallel to the strongly growing public concern about environmental problems, new ideas for trace detection and analysis of toxic and radioactive material are being developed. One of these new and outstanding experimental techniques is the application of analytical laser spectroscopy. Most interesting in this context is the method of resonance ionization spectroscopy (RIS), as proposed1 already in 1972 combining very high sensitivity in the detection of the element or isotope under investigation with high selectivity in the suppression of contaminants2–4.

Penning discharge in the KATRIN pre-spectrometer

2014

The KArlsruhe TRItium Neutrino (KATRIN) experiment is a next-generation, large-scale tritium β-decay experiment to determine the neutrino mass by investigating the kinematics of tritium β-decay with a sensitivity of 200 meV/c2 using the MAC-E filter technique. In order to reach this sensitivity a low background level of 10−2 counts per second (cps) is required. A major background concern in MAC-E filters is the presence of Penning traps. A Penning trap is a special configuration of electromagnetic fields that allows the storage of electrically charged particles. This paper describes the mechanism of Penning discharges and the corresponding measurements performed at the test setup of the KAT…

First transmission of electrons and ions through the KATRIN beamline

2018

The Karlsruhe Tritium Neutrino (KATRIN) experiment is a large-scale effort to probe the absolute neutrino mass scale with a sensitivity of 0.2 eV (90% confidence level), via a precise measurement of the endpoint spectrum of tritium β-decay. This work documents several KATRIN commissioning milestones: the complete assembly of the experimental beamline, the successful transmission of electrons from three sources through the beamline to the primary detector, and tests of ion transport and retention. In the First Light commissioning campaign of autumn 2016, photoelectrons were generated at the rear wall and ions were created by a dedicated ion source attached to the rear section; in July 2017, …

Release Studies of Atomic Technetium

1991

Application of a laser ion source (LIS) is a promising new technique for trace analysis with high efficiency and selectivity. One of the problems which can limit its efficiency attained in practice is the adsorption of sample atoms on the hot walls of the LIS cavity. We have studied the release of atomic technetium from different wall materials at temperatures up to 2500 K. For these investigations resonance ionization of technetium atoms applying a copper vapour pumped dye laser system and γ-spectrometry of 6-h 99mTc have been used. Theoretical calculations of the heat of desorption for technetium on different wall materials are presented and compared with experimental data. Though the res…

Hyperfine structure and isotope shifts of neutron-rich138?146Cs

1979

The 6s2S1/2-7p 2P3/2 transition in138–142Cs (λ=455.5 nm) has been investigated by high-resolution collinear laser spectroscopy in a fast atomic beam. The isotopes are obtained by on-line mass separation of fission products. Nuclear moments and changes of mean-square charge radii are derived from hyperfine structure and isotope shift.

The isotope shift of the radioactive Cd-isotopes (102?A?120) determined by on-line laserspectroscopy

1981

Compression of Polarized 3He

1991

This article gives a status report on the polarized 3He target development work at Mainz. It is based on the optical pumping of the 3S1 state of 3He with subsequent metastability spin exchange to the ground state atoms. This pumping scheme is very efficient at 3He pressures of about 1 Torr; for high density targets, however, a mechanical compression of the polarized gas is needed in a second step. First results with a Toepler compression pump look promising and will be discussed in the following.

Einführung in die Dynamik

1998

Wir beziehen jetzt Krafte in unsere Uberlegungen mit ein und wollen ihre Auswirkungen auf den Bewegungszustand eines Korpers studieren. Dabei stosen wir auf zwei Fragen, namlich die Frage nach dem Begriff der Kraft und die Frage nach der Wirkung der Kraft.

Ultraschnelle MRT der Lungenventilation mittels hochpolarisiertem Helium-3*

2000

Objective Assessment of the temporal and spatial dynamics of hyperpolarized Helium-3 (3He) distribution in the lung with ultrafast gradient-echo magnetic-resonance imaging. Material and methods Coronal images of the lung were acquired using ultrafast gradient-echo pulse sequences with TR/TE = 3.3 ms/1.3 ms (slice thickness, 40 mm) and TR/TE = 2.0 ms/0.7 ms (without slice selection). A series of 80 or 160 projection images was obtained with 210 ms or 130 ms temporal resolution, respectively. Imaging was performed during several respiratory cycles after application of a single bolus of 300 mL hyperpolarized 3He. Measurements were performed in six healthy volunteers (spontaneous breathing). Re…

A new upper limit of the electron anti neutrino rest mass from tritium β-decay

1993

Abstract A new upper limit of the electron anti neutrino rest mass has been deduced from the tritium β-decay spectrum. A source of molecular tritium has been investigated with a new solenoid retarding spectrometer. The results are m ν ϵ 2 = −38.8 ± 34.1 stat ± 15.1 syst (eV) 2 /c 4 from which we conclude m ν ϵ ≤ 7.2 eV/c 2 with 95% c.l. Our β-endpoint corresponds to a 3H-3He atomic mass difference of Δm( 3 H- 3 He) = 18590.8 ± 3 eV/c 2 (1σ) .

Calibration of high voltages at the ppm level by the difference of $^{83\mathrm{m}}$Kr conversion electron lines at the KATRIN experiment

2018

The neutrino mass experiment KATRIN requires a stability of 3 ppm for the retarding potential at − 18.6 kV of the main spectrometer. To monitor the stability, two custom-made ultra-precise high-voltage dividers were developed and built in cooperation with the German national metrology institute Physikalisch-Technische Bundesanstalt (PTB). Until now, regular absolute calibration of the voltage dividers required bringing the equipment to the specialised metrology laboratory. Here we present a new method based on measuring the energy difference of two [superscript 83m]Kr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN’s commissioning measurements in July 2…

Spurenbestimmung der Radionuclide90Sr und89Sr in Umweltproben I: Laser-Massenspektrometrie

1995

Nuclear Radiation Detected Optical Pumping of neutron-deficient Hg isotopes

1976

The extension of the Nuclear Radiation Detected Optical Pumping method to mass-separated samples of isotopes far off stability is presented for a series of light Hg isotopes produced at the ISOLDE facility at CERN. The isotope under investigation is transferred by an automatic transfer system into the optical pumping apparatus. Zeeman scanning of an isotopically pure Hg spectral lamp is used to reach energetic coincidence with the hyperfine structure components of the 6s 2 1 S 06s6p 3P1,λ=2,537 A resonance line of the investigated isotope and the Hg lamp. The orientation built up by optical pumping is monitored via the asymmetry or anisotropy of the nuclear radiation. Nuclear spins, magneti…

Grundtatsachen der Wärmelehre

1998

Der Warmebegriff existiert nur fur makroskopische Systeme, oder genauer gesagt, fur Systeme, die aus sehr vielen mikroskopischen Objekten (Atomen, Molekulen) zusammengesetzt sind.

He-3 spin filter for neutrons

2005

The strongly spin-dependent absorption of neutrons in nuclear spin-polarized (3)He opens up the possibility of polarizing neutrons from reactors and spallation sources over the full kinematical range of cold, thermal and hot neutrons. This paper gives a report on the neutron spin filter (NSF) development program at Mainz. The polarization technique is based on direct optical pumping of metastable (3)He atoms combined with a polarization preserving mechanical compression of the gas up to a pressure of several bar, necessary to run a NSF. The concept of a remote type of operation using detachable NSF cells is presented which requires long nuclear spin relaxation times of order 100 hours. A sh…

Application unit for the administration of contrast gases for pulmonary magnetic resonance imaging: optimization of ventilation distribution for3He-M…

2014

Purpose MRI of lung airspaces using gases with MR-active nuclei (3He, 129Xe, and 19F) is an important area of research in pulmonary imaging. The volume-controlled administration of gas mixtures is important for obtaining quantitative information from MR images. State-of-the-art gas administration using plastic bags (PBs) does not allow for a precise determination of both the volume and timing of a 3He bolus. Methods A novel application unit (AU) was built according to the requirements of the German medical devices law. Integrated spirometers enable the monitoring of the inhaled gas flow. The device is particularly suited for hyperpolarized (HP) gases (e.g., storage and administration with m…

Ultra-stable implanted 83Rb/83mKr electron sources for the energy scale monitoring in the KATRIN experiment

2012

The KATRIN experiment aims at the direct model-independent determination of the average electron neutrino mass via the measurement of the endpoint region of the tritium beta decay spectrum. The electron spectrometer of the MAC-E filter type is used, requiring very high stability of the electric filtering potential. This work proves the feasibility of implanted 83Rb/83mKr calibration electron sources which will be utilised in the additional monitor spectrometer sharing the high voltage with the main spectrometer of KATRIN. The source employs conversion electrons of 83mKr which is continuously generated by 83Rb. The K-32 conversion line (kinetic energy of 17.8 keV, natural line width of 2.7 e…

Polarized3He targets in medium energy physics at MAMI

2011

Experiments with polarized 3He targets at the Mainz Microtron (MAMI) involve double polarized photoabsorption or the extraction of the electric form factor of the neutron Ge,n via electron scattering, respectively. Polarized 3He with an initial polarization of up to 70% at the experimental areas is provided by a polarizer based on the principle of metastability exchange optical pumping (MEOP). In this article both target setups for the photon- and the electron beamlines will be described and a status of the data analysis will be given.

Normal and abnormal pulmonary ventilation: visualization at hyperpolarized He-3 MR imaging.

1996

To assess the feasibility of helium-3 magnetic resonance (MR) imaging with a three-dimensional fast low-angle shot (FLASH) sequence, He-3 gas (volume, 300 mL; pressure, 3 x 10(5) Pa; polarized up to 45% by means of optimal pumping) was inhaled by five healthy volunteers and five patients with pulmonary diseases. All breath-hold examinations (22-42 seconds) were completed successfully. Normal ventilation was depicted with homogeneous high signal intensity, lesions were depicted as causing defects, and obstructive lung disease was depicted with severely inhomogeneous signal intensity.

Drehimpuls, Drehmoment, Drehimpulssatz

1998

Wir wollen in diesem und im folgenden Kapitel die Dynamik von Drehbewegungen genauer untersuchen. Sie spielen in der Physik eine sehr grose Rolle. Zum einen geben Zentralkrafte wie die Schwerkraft und die elektrische Kraft Anlas zu Drehbewegungen um das Kraftzentrum. Zum anderen ist die Rotation um die eigene Achse ein wichtiger Freiheitsgrad der Bewegung starrer Korper. Wir fuhren hierzu zwei Begriffe ein, den Drehimpuls und das Drehmoment, die bei Drehbewegungen eine ahnliche Rolle spielen, wie der Impuls und die Kraft bei linearen Bewegungen. In Analogie zum Impuls konnen wir auch fur den Drehimpuls einen wichtigen Erhaltungssatz gewinnen.

Determination of the neutron electric form factor in the D(e,e′n)p reaction and the influence of nuclear binding

1999

The electric form factor of the neutron GE,n has been determined at the Mainz Microtron MAMI at the low momentum transfer Q2= 0.15 (GeV/c)2 in a measurement of the recoil polarisation ratio Px/Pz in the quasifree reaction D(e,e′n)p. At this Q2 the influence of the nuclear binding is strong. A purely kinematical model is used to get some insight into the effect of the initial Fermi momentum distribution of the neutron. The influence of the final state interaction is determined quantitatively by a model of Arenhovel et al.. After the corresponding corrections a value of GE,n(0.15 (GeV/c)2) = 0.0481±0.0065stat±0.0053syst is obtained.

First observation of the blue optical lines of francium

1987

We report here the first wave-length measurements in the second resonance doublet of francium, D1'(7s2S1/2-8p2P 1/2) and D2'(7s2S1/2-8p2P 3/2), carried out by collinear fast-beam laser spectroscopy. The transition wave numbers are D1' = 23112.9603(50) cm-1 and D2' = 23658.3058(40) cm-1, corresponding to a 8p fine-structure splitting of δW8p = 545.3454(70) cm-1. In addition the hyperfine structure in both lines and the isotope shift in the D2' line for the isotopes 212,213,220,221Fr have been measured. The results are discussed with special emphasis on the analysis of the atomic structure in the heaviest alkali element and compared with theoretical predictions, as well as the only earlier sp…

The Electric Formfactor of the Neutron Determined by Quasielastic Scattering of Longitudinally Polarized Electrons from 3He and 2D

1996

The recent availability of polarized electron beams at electron accelerator laboratories adds another technique to probing the electromagnetic structure of nuclear matter [1]. The present paper discusses the application of polarized electron scattering to the determination of the electric formfactor of the neutron. Its value at medium energies is only poorly known hitherto. Electron scattering is dominated by interaction with the neutron magnetic moment. Therefore the contribution of the charge distribution to the scattering cross section is scarcely detectable in case of unpolarized collision partners. The elastic scattering of longitudinally polarized electrons from a polarized neutron ta…

Comment on “Comparison of Polarization Observables in Electron Scattering from the Proton and Deuteron”

1998

Ruhende Flüssigkeiten und Gase

1998

Wir wollen in diesem Kapitel die wichtigsten mechanischen Eigenschaften und Phanomene diskutieren, die man bei ruhenden Flussigkeiten und Gasen beobachten kann. In diesem Sinne wollen wir als erstes die Definition von Flussigkeiten und Gasen aus der Sicht der Mechanik treffen.

Orientation of199mHg by optical pumping detected by ?-radiation anisotropy

1975

199mHg was produced and mass separated at the ISOLDE facility (CERN). Nuclear orientation achieved by optical pumping via the resonance line 6s21S0→6s6p3P1,λ=2537A was monitored by means of the anisotropy of theγ-radiation emitted in the cascade199mHg(I=13/2+) $${}^{199m}Hg(I = 13/2^ + )\xrightarrow[{M4}]{}{}^{199*}Hg(I = 5/2^ - )\xrightarrow[{E2}]{}{}^{199}Hg(I = 1/2^ - ).$$ 199*Hg(I=5/2−)199Hg(I=1/2−).

Drehbewegungen starrer Körper

1998

Die Bewegungsablaufe in einem System sehr vieler, miteinander wechselwirkender Massenpunkte wird man nur dann mit einfachen, ubersichtlichen Gleichungen beschreiben konnen, wenn man die Bewegungsfreiheit der Massenpunkte geeignet einschrankt. Die radikalste Einschrankung bietet in dieser Hinsicht der starre Korper, bei dem alle Massenpunkte einen festen Abstand zueinander halten. Dieser Vorstellung genugen auch die meisten festen Korper in guter Naherung, wenn man sie nicht allzu hohen Kraften aussetzt. Man braucht insgesamt sechs Koordinaten, um die Lage eines starren Korpers vollstandig zu beschreiben. Es sind dies ein Ortsvektor vom Ursprung zu einem Punkt des Korpers, in der Regel desse…

Nuclear magnetic resonance imaging with hyperpolarised helium-3

1996

Abstract Summary Background Magnetic resonance imaging (MRI) relies on magnetisation of hydrogen nuclei (protons) of water molecules in tissue as source of the signal. This technique has been valuable for studying tissues that contain significant amounts of water, but biological settings with low proton content, notably the lungs, are difficult to image. We report use of spin-polarised helium-3 for lung MRI. Methods A volunteer inhaled hyperpolarised 3 He to fill the lungs, which were imaged with a conventional MRI detector assembly. The nuclear spin polarisation of helium, and other noble gases, can be greatly enhanced by laser optical pumping and is about 10 5 times larger than the polari…

Improved limit on the electron-antineutrino rest mass from tritium ß-decay

1993

Abstract The endpoint region of the β-spectrum of tritium was remeasured by an electrostatic spectrometer with magnetic guiding field. It enabled the search for a rest mass of the electron-antineutrino with improved precision. The result is m2v=−39±34stat±15syst(eV/c2)2, from which an upper limit of mv m( T )−m( 3 He )=18 591±3 eV /c 2 .

Materie im Magnetfeld

1998

Genau wie das elektrische Feld polarisiert auch das Magnetfeld Materie zu resultierenden Dipolmomenten, die nun ihrerseits das B-Feld verandern und uns zur Einfuhrung des H-Feldes (21.14) veranlast haben. Das es hier zu drastischen Effekten kommen kann, haben wir schon bei Permanent- und Elektromagneten mit Eisenkern erfahren. Das sind aber Ausnahmeerscheinungen, die auf wenige Materialien beschrankt sind. Normalerweise reagiert Materie nur schwach auf Magnetfelder, wie wir im folgenden untersuchen werden.

Determination of spin, magnetic moment and isotopic shift of neutron rich205Hg by optical pumping

1975

Neutron rich205Hg (T 1/2=5.2 min) was produced and on-line mass separated at the ISOLDE facility at CERN. The polarization achieved by optical pumping via the atomic line (6s 21 S 0↔6s6p 3 P 1,λ=2 537A) was monitored by theβ decay asymmetry. Hyperfine structure and isotopic shift of the205Hg absorption line was determined by Zeeman scanning. In addition a magnetic resonance was performed on the polarized205Hg nuclei in the atomic ground state. The results are: $$I(^{205} Hg) = \tfrac{1}{2}$$ (confirmed);μ I (205Hg)=0.5915 (1)μ N (uncorrected for diamagnetism); isotopic shiftδv204/205=v(205Hg)-v(204Hg)=−1.8 (1) GHz.μ I and IS are discussed briefly in the frame of current literature.

Very long nuclear relaxation times of spin polarized helium 3 in metal coated cells

1995

Abstract We obtained very long relaxation times T 1 of up to 120 h for the nuclear polarization of an optically pumped helium 3 gas. The glass containers were internally coated with metallic films such as bismuth or cesium. These findings will have applications in the field of helium magnetometers and polarized targets.

A highly polarized target for the electron beam at MAMI

2009

Abstract Polarized He 3 from metastability exchange optical pumping (MEOP) is used as an effective polarized neutron target for electron scattering experiments at the MAinz MIcrotron (MAMI). With the present setup an initial polarization of up to 72% has been obtained at the experimental area. A novel calibration technique will be presented which allows the determination of the absolute polarization within a relative uncertainty of 3%.

Analysis of intrapulmonary O2concentration by MR imaging of inhaled hyperpolarized helium-3

1999

Inhalation of hyperpolarized 3He allows magnetic resonance imaging (MRI) of ventilated airspaces.3He hyperpolarization decays more rapidly when interacting with paramagnetic O2. We describe a method for in vivo determination of intrapulmonary O2 concentrations ([O2]) based on MRI analysis of the fate of measured amounts of inhaled hyperpolarized3He in imaged regions of the lung. Anesthetized pigs underwent controlled normoventilation in a 1.5-T MRI unit. The inspired O2 fraction was varied to achieve different end-tidal [O2] fractions ([Formula: see text]). With the use of a specifically designed applicator,3He (100 ml, 35–45% polarized) was administered at a predefined time within single …

Nuclear Shape Staggering in Very Neutron-Deficient Hg Isotopes Detected by Laser Spectroscopy

1977

The isotope shifts of $^{188}\mathrm{Hg}$, $^{186}\mathrm{Hg}$, and $^{184}\mathrm{Hg}$ in the 2537-\AA{} line have been measured by use of tunable dye laser at the on-line mass separator ISOLDE at CERN. The results are $\ensuremath{\delta}\ensuremath{\nu}(^{188}\mathrm{Hg}\ensuremath{-}^{204}\mathrm{Hg})=35.8(2)$ GHz; $\ensuremath{\delta}\ensuremath{\nu}(^{186}\mathrm{Hg}\ensuremath{-}^{204}\mathrm{Hg})=39.4(2)$ GHz; and $\ensuremath{\delta}\ensuremath{\nu}(^{184}\mathrm{Hg}\ensuremath{-}^{204}\mathrm{Hg})=43.1(2)$ GHz. These data combined with those obtained by $\ensuremath{\beta}$-radiation-detected optical pumping ($\ensuremath{\beta}$-RADOP) on the odd Hg isotopes yield a huge odd-even…

High-voltage measurements on the 5 ppm relative uncertainty level with collinear laser spectroscopy

2018

We present the results of high-voltage collinear laser spectroscopy measurements on the 5 ppm relative uncertainty level using a pump and probe scheme at the transition of involving the metastable state. With two-stage laser interaction and a reference measurement we can eliminate systematic effects such as differences in the contact potentials due to different electrode materials and thermoelectric voltages, and the unknown starting potential of the ions in the ion source. Voltage measurements were performed between −5 kV and −19 kV and parallel measurements with stable high-voltage dividers calibrated to 5 ppm relative uncertainty were used as a reference. Our measurements are compatible …

The quadrupole moment of the neutron-halo nucleus 11Li

1995

The quadrupole moment ratio of 9Li and 11Li was measured by a combination of in-beam laser induced nuclear polarization and β-NMR in LiNbO3. The result |Q(11Li)/Q(9Li)| = 1.14(16) is consistent with cluster models describing 11Li as composed of a 9Li core and a far extended halo of two loosely bound neutrons.

A high resolution electrostatic time-of-flight spectrometer with adiabatic magnetic collimation

1999

Abstract A new type of spectrometer for low energy charged particles is presented. It consists of an adiabatic magnetic collimation and two filters: an electrostatic retarding potential to set a lower limit (high pass) and a time-of-flight analysis to reject high energy charged particles (low pass). Both filters are only limited in their resolution by the efficiency of the adiabatic magnetic collimation. The proof of this principle is demonstrated by a pilot measurement on the K conversion line of 83mKr. Possible applications to pulsed and continuous electron sources are discussed with the emphasis on the investigation of the β spectrum of T2 to deduce information on the mass of the electro…

Properties and performance of a quadrupole mass filter used for resonance ionization mass spectrometry

1998

Abstract The performance of commercial quadrupole mass spectrometers (QMS) with a number of imperfections, as compared to the ideal hyperbolic geometry, has been characterized using the computer simulation program simion 3d version 6.0. The analysis of simulated QMS geometries focuses primarily on modeling of the internal potential, the study of field deviations, and the influence of finite length on performance of the QMS. The computer simulation of ion trajectories in the QMS field yields predictions for optimum working conditions and provides estimates for the resolving power and the maximum isotopic abundance sensitivity. Experimental measurements that confirm these expectations are pre…

Spins, moments and charge radii in the isotopic series181Hg-191Hg

1976

The hyperfine structure splitting and the isotope shift in the (6 s2 1S0 - 6s 6p3P1,λ=2,537 A) line of very neutron deficient Hg isotopes were determined by the β radiation detected optical pumping method (β-RADOP). In addition, nuclear magnetic resonance was observed in the atomic ground state. The results are Mean-square nuclear charge radii are calculated. Interpreting the sudden change of nuclear radius between187Hg and185Hg δ〈r2〉187,185=0.42(5)fm2 as oblate-prolate shape transition, one obtains δ〈β2〉 =0.054(5).

High-resolution spectroscopy of gaseous $^\mathrm{83m}$Kr conversion electrons with the KATRIN experiment

2020

In this work, we present the first spectroscopic measurements of conversion electrons originating from the decay of metastable gaseous $^\mathrm{83m}$Kr with the Karlsruhe Tritium Neutrino (KATRIN) experiment. The results obtained in this calibration measurement represent a major commissioning milestone for the upcoming direct neutrino mass measurement with KATRIN. The successful campaign demonstrates the functionalities of the full KATRIN beamline. The KATRIN main spectrometer's excellent energy resolution of ~ 1 eV made it possible to determine the narrow K-32 and L$_3$-32 conversion electron line widths with an unprecedented precision of ~ 1 %.

Erster Hauptsatz der Warmelehre

1998

Wir kehren zuruck zur makroskopischen Darstellung der Warmelehre und untersuchen den Zusammenhang zwischen innerer Energie U eines idealen Gases und dessen spezifischen Warmen. Wir wollen insbesondere den Satz von der Energieerhaltung als 1. Hauptsatz der Warmelehre formulieren und auf ideale Gase anwenden. Seine wichtigen Konsequenzen werden uns auch im 16. Kapitel beschaftigen.

Measurement of the Parity Violation in Quasi-Elastic Electroweak Electron-Scattering from 9Be

1986

In the energy range of about 300 MeV, available at the Mainz- Linac, quasi-elastic scattering dominates the total cross section at backward scattering angles. This process can therefore be detected efficiently by a gas Cerenkov-counter with large solid angle. This is a prerequisit for experiments on parity violation due to the very small asymmetry effect being of the order of 1|10-5 at these energies [1]. The counting system built, consists of 12 elliptical mirrors, imaging the Cerenkov photons seen in target direction onto photomultipliers. The mirrors cover the full azimuth for polar angles 115°≦ϑ≦145°, thus covering 20% of 4π (Fig. 1). The detector has been proved to yield a statistical …

First measurement of the electric formfactor of the neutron in the exclusive quasielastic scattering of polarized electrons from polarized 3He

1994

Abstract A first measurement of the asymmetry in quasielastic scattering of longitudinally polarized electrons from a polarized 3 He gas target in coincidence with the knocked out neutron is reported. This measurement was made feasible by the cw beam of the 855 MeV Mainz Microtron MAMI. It allows a determination of the electric formfactor of the neutron G E n independent of binding effects to first order. At Q 2 =0.31 ( GeV /c) 2 two asymmetries A ∥ ( S He ∥ q ) and A ⊥ ( S He ⊥ q ) have been measured giving A ∥ =(−7.40±0.73)% and A ⊥ =(0.89±0.30)% . The ratio A ⊥ / A ∥ is independent of the absolute value of the electron and target polarization and yields G E n =0.035±0.012±0.005.

Grundzüge der kinetischen Gastheorie

1998

Wir wollen in diesem Kapitel die Warmelehre auf eine mikroskopische Grundlage stellen, d. h. auf die statistische Bewegung der einzelnen Atome und Molekule zuruckfiihren, und zwar zunachst nur fur ideale Gase. Dies ist im Prinzip ein Lehrgebiet der statistischen Mechanik, dessen strenge, theoretische Behandlung mit elementaren Methoden nicht moglich ist. Trotzdem konnen wir hier einige wichtige Resultate erschliesen und andere auch ohne Beweis sinnvoll diskutieren.

Nuclear spin and magnetic moment of 11Li

1987

Abstract Nuclear spin and magnetic moment of 11Li have been measured by optical pumping of a fast atomic beam. The angular asymmetry of the β-radiation from the polarized nuclei was used to detect the hfs of the 2s 2 S 1 2 −2 p 2 P 1 2 resonance line and the NMR signal cubic LiF crystal lattice. The results I= 3 2 and μI=3.6673(25) n.m. indicate a pure 1p 3 2 state of the valence proton.

Determination of the neutron electric form factor from the reaction 3 He(e,e'n) at medium momentum transfer

1999

The electric form factor of the neutron GEn has been determined in double polarized exclusive 3He(e,e'n) scattering in quasi–elastic kinematics by measuring asymmetries A⊥, A∥ of the cross section with respect to helicity reversal of the electron, with the nuclear spin being oriented perpendicular to the momentum transfer q in case of A⊥ and parallel in case of A∥. The experiment was performed at the 855 MeV c. w. microtron MAMI at Mainz. The degree of polarization of the electron beam and of the gaseous 3He target were each about 50%. Scattered electrons and neutrons were detected in coincidence by detector arrays covering large solid angles. Quasi–elastic scattering events were reconstruc…

Feasibility of photoelectron sources with sharp lines of stable energy between 20 and 80 keV.

2011

Photo-absorption of γ-rays in thin Al, Co, Ti, and Mo convertors was examined with the aim to produce quasi monoenergetic photoelectrons having an energy spread of 0.5-4.7eV about mean kinetic energies at discrete values between 18632 and 80321eV. The photoelectron rates were estimated for commercial photon sources of (241)Am, (119m)Sn, (125m)Te and (109)Cd with activities of 0.55-3.7GBq. Photoelectrons ejected by (241)Am γ- and X-rays from Co convertors were measured with two different electron spectrometers and obtained energy spectra were compared with Monte Carlo predictions.

Hyperfine structure studies in the 6s 6p3P2-level of barium

1991

The hfs of the3P2 state of the 6s 6p configuration of atomic barium has been determined for137Ba, applying the collinear fast-beam laser spectroscopy. The data fill the last gap in the experimental information on low lying 6s2, 6s 6p, 6s 5d and 6p 5d configurations of this alcaline earth system. The results are analyzed in terms for the existing semi-empirical modified Breit-Wills theory (MBWT), working with two basic wave functions, as well as by an extension to six-component wave functions of inclusion of configuration interaction. The semi-empirical approaches lead to a consistent description of the different hyperfine structures; they are compared with the results from recent ab initio …

Topics in atomic hyperfine structure and isotope shift

1976

Recent developments in atomic hyperfine structure and isotope shift are discussed under the following aspects: (i) Precise evaluation of nuclear moments and isotopic change of nuclear charge radii by quantitative computation of atomic structure or by calibration of the atomic constants through results from electronic and mesic X-ray spectroscopy. (ii) How to apply spectroscopic methods to nuclei far off stability. (iii) What can be learned from a systematic investigation of long isotopic chains.

Kreisprozesse und zweiter Hauptsatz der Wärmelehre

1998

Wir haben in Kap. 15 mit dem Studium der vier Modellprozesse isochor, isobar, isotherm und adiabatisch alle Vorbereitungen getroffen, um eine Warmekraftmaschine und deren Wirkungsgrad zu untersuchen. Das fuhrt uns weiter zur Diskussion irreversibler und reversibler Prozesse und damit zum 2. Hauptsatz der Warmelehre und zum Begriff der Entropie.

High-Resolution Spectroscopy in Fast Atomic Beams

1977

Narrow optical resonances have been observed in fast beams of Na and Cs atoms, obtained from ion beams by charge-transfer collisions with Na, K, or Cs. Corresponding to the narrowing of the velocity distribution, occurring by acceleration, the Doppler width along the beam direction is considerably reduced [1, 2].

A White Paper on keV sterile neutrino Dark Matter

2017

We present a comprehensive review of keV-scale sterile neutrino Dark Matter, collecting views and insights from all disciplines involved - cosmology, astrophysics, nuclear, and particle physics - in each case viewed from both theoretical and experimental/observational perspectives. After reviewing the role of active neutrinos in particle physics, astrophysics, and cosmology, we focus on sterile neutrinos in the context of the Dark Matter puzzle. Here, we first review the physics motivation for sterile neutrino Dark Matter, based on challenges and tensions in purely cold Dark Matter scenarios. We then round out the discussion by critically summarizing all known constraints on sterile neutrin…

T2-beta-spectroscopy at KATRIN and the challenge of controlling the electrostatic potentials

2013

Abstract The KATRIN-Collaboration at KIT-Karlsruhe is setting up a huge electrostatic spectrometer in order to search for the absolute value of the neutrino mass from the beta-spectrum of molecular tritium with a sensitivity limit of 0.2 eV. Apart from high intensity, high resolution and low background, this goal requires control of the 18.6 kV filter potential on the ppm level. The paper starts with discussing the impact of uncertainties of beta-endpoint, energy loss and filter potential on the uncertainty of the neutrino mass. Then it describes the various measures for controlling the applied high voltage as well as the potential distribution within the spectrometer and the gaseous tritiu…

Laser Spectroscopy of Short-Lived Isotopes in Fast Atomic Beams and Resonance Cells

1979

The introduction of laser techniques to optical spectroscopy of hyperfine structure (HFS) and isotope shift (IS) has put new life into this field at the intersection between atomic and nuclear physics which is now about fifty years old. Two severe limitations of classical spectroscopy could be reduced drastically, i.e., (i) the amount of atoms needed for optical spectroscopy and (ii) the Doppler width of optical lines. The increase in sensitivity went together with the development of powerful accelerators or reactors so that exotic nuclei with half lives down to 10 msec can now be produced and optically analysed. The increase in resolution allows the determination of nuclear spins, nuclear …

Nuclear spins of76Rb and119Cs by? radiation detected optical pumping

1978

An optical pumping apparatus has been attached to the reconstructed ISOLDE on-line mass separator at CERN in order to obtain nuclear data of isotopes far fromβ stability. As first results the spins of76Rb (T 1/2=36.8 s) and119Cs (T 1/2=37.7 s) have been determined byβ radiation detected optical pumping (β-RADOP) to beI=1 andI=9/2 respectively.

Activity monitoring of a gaseous tritium source by beta induced X-ray spectrometry

2013

Abstract For monitoring and control of gaseous tritium sources in fuel circulation systems of fusion reactors beta induced X-ray spectrometry (BIXS) seems to be an applicable method. The characteristics of a BIXS monitoring setup built at TLK were examined. A low-noise silicon drift detector (SDD) was used together with two thin beryllium windows evaporated with gold films of 100 nm for efficient X-ray production. The measured X-ray intensity was proportional to the tritium partial pressure and the average detection efficiency was evaluated as 32.6 × 10−8 cps/Bq. A tritium memory effect was revealed. From the results it was concluded that such a monitoring system would be a useful complemen…

Energy calibration and monitoring of the KATRIN experiment

2011

A new high precision voltage divider has been built for monitoring the analysing potential of the KATRIN main spectrometer. In addition a condensed 83mKr calibration source has been set up at the modified 1 eV resolving Mainz spectrometer, our measurements show that energy calibration and monitoring for KATRIN is feasible at the few ppm level.

Hyperfine structure and isotope shift investigations in $^{202-222}$Rn for the study of nuclear structure beyond Z = 82

1986

The hyperfine structure (hfs) and isotope shift (IS) in the isotopic chain of the radioactive element radon have been studied for the first time. The measurements were carried out by collinear fast-beam laser spectroscopy at the mass separator facility ISOLDE at CERN. The IS between 16 isotopes in the mass range 202≦A≦222 and the hfs of 7 odd-A isotopes were determined in the transitions 7s [3/2]2-7p [5/2]3 (745 nm) of Rn I. The nuclear spins and moments, as well as the observed inversion of the odd-even staggering for218–222Rn, can be associated with the effects of octupole instability around N=134.

Maxwellsche Gleichungen und elektromagnetische Wellen

1998

Wir wollen in diesem Kapitel die Grundlagen der Elektrodynamik abschliesen, indem wir den vollstandigen Satz ihrer Grundgleichungen zusammenfassend besprechen. Die meisten hatten wir in den Kap. 19 bis 23 bereits kennengelernt. Es fehlt uns noch das Gesetz uber den Maxwellschen Verschiebungsstrom, der entscheidend am Auftreten elektromagnetischer Wellen beteiligt ist, dem zweiten zentralen Thema dieses Kapitels. Uber die gewaltige Kraft dieses Gleichungssystems hatten wir bereits in der Einfuhrung in die elektromagnetischen Erscheinungen in Kap. 19 gesprochen. Zum einen war es dieser Theorie gelungen, alle bis dahin bekannten elektromagnetischen Erscheinungen unter das gemeinsame Dach von w…