Search results for "Ion source"
showing 10 items of 337 documents
Measurement of the first ionization potential of astatine by laser ionization spectroscopy
2013
The radioactive element astatine exists only in trace amounts in nature. Its properties can therefore only be explored by study of the minute quantities of artificially produced isotopes or by performing theoretical calculations. One of the most important properties influencing the chemical behaviour is the energy required to remove one electron from the valence shell, referred to as the ionization potential. Here we use laser spectroscopy to probe the optical spectrum of astatine near the ionization threshold. The observed series of Rydberg states enabled the first determination of the ionization potential of the astatine atom, 9.31751(8) eV. New ab initio calculations are performed to sup…
Gas jet studies towards an optimization of the IGISOL LIST method
2011
Abstract Gas jets emitted from an ion guide have been studied as a function of nozzle type and gas cell-to-background pressure ratio in order to obtain a low divergent, uniform jet over a distance of several cm. The jet has been probed by imaging the light emitted from excited argon or helium gas atoms. For a simple exit hole or converging-diverging nozzle, the jet diameter was found to be insensitive to the nozzle shape and inlet pressure. Sonic jets with a FWHM below 6 mm were achieved with a background pressure larger than 1 mbar in the expansion chamber. The measurements are supported by the detection of radioactive 219 Rn recoils from an alpha recoil source mounted within the gas cell.…
Consumers perception of food safety related risk in the italian market
2019
The aim of this paper is to define the factors affecting the consumers' perception on food risk associated to the consumption of products (i) containing food additives, (ii) obtained with the use of pesticides, and (iii) processed through novel food technologies, in relation to different socio-economic and demographic characteristics, the source of acquisition of information on food safety issues, and the place of purchase of food. The study is based on a sample of 392 consumers, living in Italy, and it uses three ordered probit estimation models to process data collected. Findings show that food risk perception is greater among youngsters, mainly for the additives and residual pesticides i…
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, …
Experimental evidence on photo-assisted O$^-$ ion production from Al$_2$O$_3$ cathode in cesium sputter negative ion source
2020
The production of negative ions in cesium sputter ion sources is generally considered to be a pure surface process. It has been recently proposed that ion pair production could explain the higher-than-expected beam currents extracted from these ion sources, therefore opening the door for laser-assisted enhancement of the negative ion yield. We have tested this hypothesis by measuring the effect of various pulsed diode lasers on the O$^-$ beam current produced from Al$_2$O$_3$ cathode of a cesium sputter ion source. It is expected that the ion pair production of O$^-$ requires populating the 5d electronic states of neutral cesium, thus implying that the process should be provoked only with s…
Resonant ionization spectroscopy of autoionizing Rydberg states in cobalt and redetermination of its ionization potential
2017
Multi-step resonance ionization spectroscopy of cobalt has been performed using a hot-cavity laser ion source and three Ti:Sapphire lasers. The photoionization spectra revealed members of five new autoionizing Rydberg series that originate from three different lower levels of 3d74s5s h4F9/2, 3d74s4d f4G11/2, and 3d74s4d f4H13/2 and converge to the first four excited states of singly ionized Co. The analyses of the Rydberg series yield 63564.689 �� 0.036 cm-1 as the first ionization potential of Co, which is an order of magnitude more accurate than the previous estimation. Using a three-step resonance ionization scheme that employs an autoinizing Rydberg state in the last transition, we obta…
High current proton beams production at Simple Mirror Ion Source 37
2014
This paper presents the latest results of high current proton beam production at Simple Mirror Ion Source (SMIS) 37 facility at the Institute of Applied Physics (IAP RAS). In this experimental setup, the plasma is created and the electrons are heated by 37.5 GHz gyrotron radiation with power up to 100 kW in a simple mirror trap fulfilling the ECR condition. Latest experiments at SMIS 37 were performed using a single-aperture two-electrode extraction system. Proton beams with currents up to 450 mA at high voltages below 45 kV were obtained. The maximum beam current density was measured to be 600 mA/cm2. A possibility of further improvement through the development of an advanced extraction sy…
Laser spectroscopy of the 1001nm ground state transition in dysprosium
2018
We present a direct excitation of the presumably ultranarrow $1001\ensuremath{-}\mathrm{nm}$ ground-state transition in atomic dysprosium. By using resonance ionization spectroscopy with pulsed Ti:sapphire lasers at a hot cavity laser ion source, we were able to measure the isotopic shifts in the $1001\ensuremath{-}\mathrm{nm}$ line between all seven stable isotopes. Furthermore, we determined the upper level energy from the atomic transition frequency of the $^{164}\mathrm{Dy}$ isotope as $9991.004(1)\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ and confirm the level energy listed in the NIST database. Since a sufficiently narrow natural linewidth is an essential prerequisit…
Spin polarisation and dichroism in ARUPS from thin rare earth films
2001
Abstract In the present study, spin polarisation and dichroism were investigated in angular resolved VUV photoemission ARUPS from magnetised as well as paramagnetic rare earth surfaces. Thin Gd(0001) films were prepared epitaxially on W(110). The photoelectrons were excited by polarised synchrotron radiation from the BESSY I synchrotron radiation source. A SPLEED detector attached to an electron spectrometer mounted on a single axis goniometer was used for angular resolved spin analysis. The main part of this work focused on the characteristic surface state of Gd(0001) which shows a splitting, as previously observed by linear magnetic dichroism and spin polarised photoemission. The spin ana…
Position-sensitive ion detection in precision Penning trap mass spectrometry
2009
A commercial, position-sensitive ion detector was used for the first time for the time-of-flight ion-cyclotron resonance detection technique in Penning trap mass spectrometry. In this work, the characteristics of the detector and its implementation in a Penning trap mass spectrometer will be presented. In addition, simulations and experimental studies concerning the observation of ions ejected from a Penning trap are described. This will allow for a precise monitoring of the state of ion motion in the trap.