Search results for "accelerator"
showing 10 items of 1507 documents
Electron beam studies of light collection in a scintillating counter with embedded fibers
2021
The light collection of several fiber configurations embedded in a box-shaped plastic scintillating counter was studied by scanning with minimum ionizing electrons. The light was read out by silicon photomultipliers at both ends. The light yield produced by the 855-MeV beam of the Mainz Microtron showed a strong dependence on the transverse distance from the beam position to the fibers. The observations were modeled by attributing the collection of indirect light inside of the counter and of direct light reaching a fiber to the total light yield. The light collection with fibers was compared to that of a scintillating counter without fibers. These studies were carried out within the develop…
NUCLEAR STRUCTURE ADDRESSED AT GSI/RISING
2009
Nuclear structure spectroscopy studies at GSI recently gained increased momentum within a broad international community with the installation of the Rare Isotopes Spectroscopic INvestigation at GSI (RISING) project. A wide range of physical phenomena has been addressed by high-resolution in-beam γ-ray spectroscopy experiments with radioactive beams. Relativistic radioactive beams are implanted and their subsequent γ and β decay is investigated. Within this "stopped beam campaign" germanium detectors were arranged in a close geometry around the passive stopper or an array of DSSSD detectors. The exceptionally high γ-ray efficiency of that configuration made it possible to identify decays of…
The polytron as a cw electron accelerator in the 10 GeV range
1991
Abstract This article is concerned with a generalized microtron, characterized essentially by the number of magnet pairs in its bending system. It is shown that the most serious physical energy limit of the microtron, emittance growth due to synchrotron radiation, may be overcome if this number is raised essentially above what has been considered in the past. The main properties of such “polytrons” are investigated and several design examples for 15 GeV output energy are discussed.
Resonant transition radiation in the X-ray region from a low emittance 855 MeV electron beam
1994
The interference of transition radiation coherently produced from a periodic stack of four polyimide foils of 7.2 μm thickness and a separation of 162 μm was investigated. This stack has been brought into the low emittance (3 π nm rad) electron beam of the 855 MeV Mainz Microtron MAMI. Transition radiation was observed in the energy range from 2 to 15 keV with a LN2-cooled pin photodiode. A good energy resolution of 0.8 keV and angular resolution of 0.15 mrad was achieved simultaneously allowing for the first time to quantitatively study the interference pattern. Good agreement with theoretical calculations is found. Prospects to exploit transition radiation in the x-ray region from a low e…
Transverse laser cooling of a radio-frequency bunched ion beam in the storage ring TSR
1996
Abstract We report on the observation of the indirect transverse laser cooling effect in a radio-frequency bunched beam of 7.3 MeV 9 Be + ions, stored in the Heidelberg Test Storage Ring and subject to direct longitudinal laser cooling. This bunched scheme offers particular advantages for producing ultracold beams with unprecedented phase-space densities.
THE COMPTON BACKSCATTERING POLARIMETER OF THE A4 EXPERIMENT
2005
Abstract The A4 collaboration at the Institut fur Kernphysik, University of Mainz, is conducting experiments on single-spin asymmetries in the elastic electron–nucleon-scattering which require polarized beams. In order to measure the absolute beam polarization, we have installed a Compton backscattering polarimeter in front of the target, using for the first time the internal cavity concept. A maximum intra-cavity intensity of 90 W has been measured, and in August 2003, first backscattered photons have been detected. Recently, first Compton asymmetries have been measured.
Production cross-sections and neutron polarization in (p,n) reactions at 143 MeV
1963
Abstract Measurements have been made of the energy spectra and polarizations of neutrons emitted at a laboratory angle of 45° from deuterium, lithium and aluminium bombarded by protons of 143 MeV. The results are consistent with the view that neutron production from deuterium proceeds mainly by single quasi-free proton-neutron scattering but that multiple scattering effects predominate in heavier nuclei.
Tests of the Standard Model with Low-Energy Neutrino Beams
2007
We discuss the possibility of using future high--intensity low--energy neutrino beams for precision tests of the Standard Model. In particular we consider the determination of the electroweak mixing angle from elastic and quasi--elastic neutrino--nucleon scattering at a superbeam or $\beta$--beam.
Small angle scattering from oriented latent nuclear tracks
1984
Abstract Using X-ray and neutron small-angle scattering we studied the defects in mica created by irradiation with uranium ions delivered from the UNILAC accelerator at GSI (Darmstadt, Germany). The defects are regions of reduced density and are best described as cylinders with Gaussian radial density distribution. Scaling laws are given for the time development and the energy dependence of the track parameters.
A Møller polarimeter for CW and pulsed intermediate energy electron beams
1990
The Moller polarimeter was mainly designed for the cw electron beam of the Mainz microtron (MAMI). The described polarimeter covers an energy range between 25 and 185 MeV and can relatively simply be upgraded to the maximum MAMI energy of 840 MeV. The Moller-scattered electrons are momentum-analyzed in the defocusing plane of a quadrupole magnet and both Moller electrons can be detected in coincidence for symmetrical scattering with ⊖cm=90°. All polarization components of the electron beam can be measured by suitable choices of the orientation of the target polarization. For pulsed electron beams with a small duty factor and a high peak current the polarimeter can also be operated with sing…