Search results for "Accelerator"

Positron Annihilation in Corroded Steels St20 and St3S

2006

The paper deals with examining the lifetimes of positrons emitted from Na source in corroded St20 and St3S steels. Influence of the method of defecting the sample surfaces on the spectrum of positron lifetimes was investigated. Influence of temperature of initial annealing of samples, plastic deformation, electrolytic hydrogenation and corrosion in HCl vapors on trapping positrons in the examined steels was also determined.

Two-body photodisintegration of the deuteron from 100 to 800 MeV

1996

Abstract The total and the differential cross sections for the D(γ,p)n reaction have been measured over the photon energy range 100-800 MeV at the 855 MeV MAMI Microtron in Mainz. Using the large acceptance detector DAPHNE in conjunction with the Glasgow tagging spectrometer, high precision results with small systematic errors were obtained. The data are presented in the form of thirty-five angular distributions at c.m. proton angles between 30°–160° in 10° intervals and at photon energies in steps of 20 MeV. Previous experimental work is reassessed in the light of the present results and comparison with some recent theoretical calculations.

Observation ofY(3940)→J/ψωinB→J/ψωKatBABAR

2008

We present a study of the decays B;{0,+}-->J/psiomegaK;{0,+} using 383x10;{6} BB[over ] events obtained with the BABAR detector at PEP-II. We observe Y(3940)-->J/psiomega, with mass 3914.6_{-3.4};{+3.8}(stat)+/-2.0(syst) MeV/c;{2}, and width 34_{-8};{+12}(stat)+/-5(syst) MeV. The ratio of B0 and B+ decay to YK is 0.27_{-0.23};{+0.28}(stat)-0.01+0.04(syst), and the relevant B0 and B+ branching fractions are reported.

Polarimetry at MAMI

2013

Moller and Mott polarimeters have been compared concerning their measurement accuracy in a dedicated "spin dance" experiment. The results obtained with the different polarimeters at vastly different energy ranges were in agreement with each other within the given systematic uncertainties of a few percent. We discuss investigations of background conditions which may allow to reduce this important contribution to the uncertainties in the Mott polarimeter to a value below 1.0%.

Design, construction and performance of the energy compressing system of the Mainz 300 MeV electron linac

1973

Abstract For the sake of better energy resolution of the 300 MeV electron linac of Mainz university a system has been built which transforms a sharply bunched beam of poor energy resolution into a beam of sharply defined energy, while its bunches are smeared out. The system is described, its design philosophy and some essential construction details are given. The operating experience of the last 6 months since completion of the system is communicated.

Experiments at the electron accelerator MAMI

2008

Stellar(n,γ)Cross Section ofNi62

2005

The 62Ni(n,gamma)63Ni(t(1/2)=100+/-2 yr) reaction plays an important role in the control of the flow path of the slow neutron-capture (s) nucleosynthesis process. We have measured for the first time the total cross section of this reaction for a quasi-Maxwellian (kT=25 keV) neutron flux. The measurement was performed by fast-neutron activation, combined with accelerator mass spectrometry to detect directly the 63Ni product nuclei. The experimental value of 28.4+/-2.8 mb, fairly consistent with a recent calculation, affects the calculated net yield of 62Ni itself and the whole distribution of nuclei with 62<A<90 produced by the weak s process in massive stars.

The energy loss system of the electron scattering facility at the Mainz 300 MeV linear accelerator

1978

Abstract An energy loss system was constructed for the electron scattering facility at the Mainz 300 MeV linear accelerator with the aim of improving the energy resolution and increasing the useful beam current. The main features of the design are: (1) the existing system (conventional mode) is kept in full operation, (2) for the energy loss mode, the electron beam is deflected vertically downwards and then returned to the original beam line by the dispersion matching system, consisting of three dipole magnets and one quadrupole magnet, (3) the dispersion of the beam on the target can be tuned to the dispersion of the spectrometer with the aid of the quadrupole magnet. With the installation…

Beam optics and magnet technology of the microtron in mainz

1981

Abstract A description is given of the beam transport system for injection into the first microtron of MAMI. Further, a special procedure to improve the field distribution of the dipole magnets is described in some detail and results are given.

Nucleon Form Factor Measurements in Mainz: Past and Future

2007

The form factors of proton and neutron provide a natural and direct insight into their internal structure. They were a main research goal in the nuclear physics program of the Universitat Mainz, which led to some of the most precise measurements to date. This article gives an overview, starting from the very first experiments at the now obsolete linear accelerator and ending at the exhaustive experiments currently underway at the Mainz Microtron (MAMI) facilities.