Search results for "Microtron"
showing 9 items of 149 documents
The Institute for Nuclear Physics at the University of Mainz
2008
MAMI, the MAinz MIcrotron, has become a synonym for a cw electron scattering facility in the 1.5 14;GeV range with an outstanding beam quality and reliability. The Institute for Nuclear Physics (IKP) at the Johannes Gutenberg-University of Mainz, the home of MAMI, has developed and built this cascade of four recirculating machines for precision scattering experiments mostly with polarized electrons and photons for research in the field of hadron and nuclear physics. The central physics topic is the investigation of strongly interacting systems with the electroweak probe. This field, nowadays called strong QCD, which means QCD in the strongly coupled, non perturbative regime, still poses a n…
Highlights and perspectives of the Mainz microtron MAMI
2003
Abstract An overview of the idea behind the physics of the MAMI laboratory and its realization is given. The introduction attempts to show the importance of the physics of hadrons in the general realm and emphasizes the low energy domain as the key to study Quantum Chromo Dynamics (QCD). Next some highlights of results at MAMI are presented illustrating this idea. New significant experiments to proceed with this approach to QCD are discussed. This is followed by a description of the upgrade of the existing MAMI B with 0.885 GeV to MAMI C with 1.5 GeV and of the new experimental equipment making the new experiments possible.
On the operation of silicon photomultipliers at temperatures of 1–4 kelvin
2016
Abstract SiPM operation at cryogenic temperatures fails for many common devices. A particular type from Zecotek with deep channels in the silicon substrate instead of quenching resistors was tested at liquid helium temperature. Two similar types were thoroughly characterized from room temperature down to liquid nitrogen temperature by illuminating them with low light levels. At cryogenic temperatures the SiPMs show an unchanged rise-time and a fast recovery time, practically no after-pulses, and exhibit no increased cross-talk probability. Charge collection spectra were measured to extract the pixel gain and its variation, both comparable to room temperature at the same over-voltage. The qu…
Investigation of the Electromagnetic Radiation Emitted by Sub-GeV Electrons in a Bent Crystal.
2015
The radiation emitted by 855 MeV electrons via planar channeling and volume reflection in a $30.5\text{\ensuremath{-}}\ensuremath{\mu}\mathrm{m}$-thick bent Si crystal has been investigated at the MAMI (Mainzer Mikrotron) accelerator. The spectral intensity was much more intense than for an equivalent amorphous material, and peaked in the MeV range in the case of channeling radiation. Differently from a straight crystal, also for an incidence angle larger than the Lindhard angle, the spectral intensity remains nearly as high as for channeling. This is due to volume reflection, for which the intensity remains high at a large incidence angle over the whole angular acceptance, which is equal t…
Deuteron form factor measurements at low momentum transfers
2016
A precise measurement of the elastic electron-deuteron scattering cross section at four-momentum transfers of 0.24 fm−1 ≤ Q ≤ 2.7 fm−1 has been performed at the Mainz Microtron. In this paper we describe the utilized experimental setup and the necessary analysis procedure to precisely determine the deuteron charge form factor from these data. Finally, the deuteron charge radius rd can be extracted from an extrapolation of that form factor to Q 2 = 0.
The Computer Control Software for MAMI
1980
The computer control system of the Mainz Microtron is designed to keep track with the modular and step-by-step construction of the three accelerator stages. The system is up to now based on two loosely coupled HP1000 minicomputers, interfaced via CAMAC to the accelerator components and to the operator desk. The control software is divided into several layers of portable processes distributed to both computers. Communication between the processes, access to the data bank and the routing of CAMAC interrupts are handled via a message system which operates with symbolic addresses.
First measurement of proton's charge form factor at very low $Q^2$ with initial state radiation
2017
We report on a new experimental method based on initial-state radiation (ISR) in e-p scattering, in which the radiative tail of the elastic e-p peak contains information on the proton charge form factor ($G_E^p$) at extremely small $Q^2$. The ISR technique was validated in a dedicated experiment using the spectrometers of the A1-Collaboration at the Mainz Microtron (MAMI). This provided first measurements of $G_E^p$ for $0.001\leq Q^2\leq 0.004 (GeV/c)^2$.
Exclusive measurement of quasi-free η-photoproduction from deuterium
2003
Quasi-free photoproduction of eta-mesons from the deuteron has been measured at the tagged photon facility of the Mainz microtron MAMI with the photon spectrometer TAPS for incident photon energies from the production threshold at 630 MeV up to 820 MeV. In a fully exclusive measurement eta-mesons and recoil nucleons were detected in coincidence. At incident photon energies above the production threshold on the free nucleon, where final state interaction effects are negligible, an almost constant ratio of sigma(n)/sigma(p)=0.66+/-0.10 was found. At lower incident photon energies the ratio rises due to re-scattering effects. The average ratio agrees with the value extracted from a comparison …
STATUS OF STRANGENESS ELECTRO-PRODUCTION AT MAMI
2009
At the Institut für Kernphysik in Mainz, Germany, the microtron MAMI has been upgraded to 1.5 GeV electron beam energy and can now be used to study strange hadronic systems. The magnetic spectrometer KAOS from GSI was dismantled and re-installed in the spectrometer facility operated by the A1 collaboration. The spectrometer's primary purpose is to study strangeness electro-production. Its compact design and its capability to detect negative and positive charged particles simultaneously under forward scattering angles complements the existing spectrometers. In 2008, an important milestone has been reached by the successful measurement of kaon production off a liquid hydrogen target. The ide…