The OLYMPUS experiment Milner, R.; Hasell, D.K.; Kohl, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2014, Letnik:
741
Journal Article
Recenzirano
The OLYMPUS experiment was designed to measure the ratio between the positron–proton and electron–proton elastic scattering cross-sections, with the goal of determining the contribution of two-photon ...exchange to the elastic cross-section. Two-photon exchange might resolve the discrepancy between measurements of the proton form factor ratio, μpGEp/GMp, made using polarization techniques and those made in unpolarized experiments. OLYMPUS operated on the DORIS storage ring at DESY, alternating between 2.01GeV electron and positron beams incident on an internal hydrogen gas target. The experiment used a toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight detectors to measure rates for elastic scattering over the polar angular range of approximately 25°–75°. Symmetric Møller/Bhabha calorimeters at 1.29° and telescopes of GEM and MWPC detectors at 12° served as luminosity monitors. A total luminosity of approximately 4.5fb−1 was collected over two running periods in 2012. This paper provides details on the accelerator, target, detectors, and operation of the experiment.
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A two-dimensional thermal-neutron detector developed for a small-angle diffractometer by the Petersburg Nuclear Physics Institute is described. The detector, with a sensitive area of 600 × 600 mm
2
..., is based on a multiwire proportional chamber. A gas mixture containing
3
He is the neutron converter. A new technology for manufacturing electrodes has been developed and used to increase both the gas purity and the lifetime of the detector without refilling its working volume under the experimental conditions. Data acquisition is carried out by the readout system based on the method of cathode-strip data readout to an
LC
delay line, which is located inside the detector. The detector is operable in a vacuum owing to its design.
Ultracold neutron detector for neutron lifetime measurements Andreev, V.; Vassiljev, A.; Ivanov, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2017, Letnik:
845
Journal Article
Recenzirano
The gas-filled detector of ultracold neutrons has been designed and constructed for the spectrometer of the neutron lifetime measurements at the ILL, Grenoble, France. The detector has been ...successfully tested and is currently being used at this spectrometer. We could show that minimization of the “wall” effect is a key factor to ensure efficient background suppression and to maximize the detection efficiency. This effect is primarily related to the composition of the gas mixture, which crucially depends on the neutron velocity spectrum.
The EPECUR collaboration presents new high precision data on the pion-proton elastic scattering in the second resonance region. The experiment EPECUR is placed on the universal beam channel of the ...accelerator ITEP. The setup features 0.1% beam pion momentum tagging system, 25 cm long liquid hydrogen target, placed in mylar container and beryllium outer shell, low material wire drift chambers and high performance DAQ. More than 3 billions of triggers have been collected. The data cover pion beam momentum range 0.8 - 1.3 GeV/c and 40-120 degrees center-of-mass scattering angle range for both positive and negative pions. The measured differential cross section has 2% statistical accuracy in 2 degrees angle and 5 MeV/c momentum intervals.
Aging tests of full-scale CMS muon cathode strip chambers Acosta, D.; Apollinari, G.; Arisaka, K. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2003, Letnik:
515, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Two CMS production Cathode Strip Chambers were tested for aging effects in a high-radiation environment at the Gamma Irradiation Facility at CERN. The chambers were irradiated over a large area: in ...total, about 2.1
m
2 or 700
m of wire in each chamber. The 40% Ar+50% CO
2+10% CF
4 gas mixture was provided by an open-loop gas system for one of the chambers and by a closed-loop re-circulating gas system for the other. After an accumulation of 0.3–0.4
C/cm of a wire, equivalent to about 30–50 years of operation at peak LHC luminosity, no significant changes in gas gain, chamber efficiency and wire signal noise were observed for either of the two chambers. The only consistent signs of aging were a small increase in dark current from ∼2 to ∼10
nA per plane of 600 wires and a decrease of strip-to-strip resistance from 1000 to 10–100
GΩ. Disassembly of the chambers revealed deposits on the cathode planes, while the anode wires remained fairly clean.
NeuLAND (New Large-Area Neutron Detector) is the next-generation neutron detector for the R3B (Reactions with Relativistic Radioactive Beams) experiment at FAIR (Facility for Antiproton and Ion ...Research). NeuLAND detects neutrons with energies from 100 to 1000 MeV, featuring a high detection efficiency, a high spatial and time resolution, and a large multi-neutron reconstruction efficiency. This is achieved by a highly granular design of organic scintillators: 3000 individual submodules with a size of 5 × 5 × 250 cm3 are arranged in 30 double planes with 100 submodules each, providing an active area of 250 × 250 cm2 and a total depth of 3 m. The spatial resolution due to the granularity together with a time resolution of σt≤ 150 ps ensures high-resolution capabilities. In conjunction with calorimetric properties, a multi-neutron reconstruction efficiency of 50% to 70% for four-neutron events will be achieved, depending on both the emission scenario and the boundary conditions allowed for the reconstruction method. We present in this paper the final design of the detector as well as results from test measurements and simulations on which this design is based.
A method of noninvasive recovery of gas-discharge detectors degraded due to operation in intense radiation fields is described. The plasma-chemical reactions are the basis of the presented ...techniques; these reactions take place during the detector training in a gas discharge of special recovering gas mixtures. The results of recovery of operating parameters for proportional chambers and counters are presented.
Two-dimensional thermal neutron detector Andreev, V. A.; Ivanov, E. A.; Ilyin, D. S. ...
Bulletin of the Russian Academy of Sciences. Physics,
07/2008, Letnik:
72, Številka:
7
Journal Article
Recenzirano
A two-dimensional thermal neutron detector for neutron diffraction experiments has been developed and designed at the St. Petersburg Nuclear Physics Institute, Russian Academy of Sciences. The ...detector is based on a multiwire proportional chamber with cathode-strip delay line readout. The detector aperture is 170 × 300 mm
2
and the anode wire spacing is 4 mm. The chamber is filled with a 1.5 atm
3
He + 2 atm CF
4
gas mixture. To conserve high purity of the gas mixture, all electrodes are made of quartz glass. The spatial resolution of the detector is 2.5 mm and the detection efficiency is 60% for 9 Å neutrons.
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