Avalanche fluctuations set a limit to the energy and position resolutions that can be reached by gaseous detectors. This paper presents a method based on a laser test-bench to measure the absolute ...gain and the relative gain variance of a Micro-Pattern Gaseous Detector from its single-electron response. A Micromegas detector was operated with three binary gas mixtures, composed of 5% isobutane as a quencher, with argon, neon or helium, at atmospheric pressure. The anode signals were read out by low-noise, high-gain Cremat CR-110 charge preamplifiers to enable single-electron detection down to gain of 5 10 super(3) for the first time. The argon mixture shows the lowest gain at a given amplification field together with the lowest breakdown limit, which is at a gain of 210 super(4) an order of magnitude lower than that of neon or helium. For each gas, the relative gain variance f is almost unchanged in the range of amplification field studied. It was found that f is twice higher (f~0.6) in argon than in the two other mixtures. This hierarchy of gain and relative gain variance agrees with predictions of analytic models, based on gas ionisation yields, and a Monte-Carlo model included in the simulation software Magboltz version 10.1.
The PANDA collaboration at FAIR, Germany, will employ antiproton annihilations to investigate yet undiscovered charm-meson states and glueballs. The aim is to study QCD phenomena in the ...non-perturbative regime and to unravel the origin of hadronic masses. A multi-purpose detector for tracking, calorimetry and particle identification is presently being developed to run at high luminosities providing up to 2×107 interactions/s. One of the crucial components of the PANDA spectrometer is the Electromagnetic Calorimeter, composed of cooled PbWO4 crystals. This paper describes construction and performance of a fully functioning prototype of this calorimeter. The performance was determined from measurements exploiting cosmic muons and high-energy tagged photons from the MAMI-C electron accelerator. The response measurements were carried out using sampling ADCs and, for comparison, charge-integrating ADCs. The achieved results validate the usage of sampling ADCs with a moderate sampling frequency, provide the energy resolution as foreseen in the Technical Design Report of the full calorimeter, and secure event correlation by achieving a good timing resolution through digital analysis of the sampled signals.
Young (20-30-year-old) and older (60-76-year-old) adults were tested on two measures of rhythmic performance. The first involved tapping at the subject's own preferred rate, a measure of so-called ...internal tempo. Over five sessions of testing, tapping rates were consistently and significantly slower on average in the older subjects than the younger ones, but rates were not relatively more variable in older subjects (i.e., coefficients of variation, standard deviation/mean, did not differ between the older and young people). In addition, both old and younger subjects performed on a synchronized-tapping and continuation task of the type used by Wing and Kristofferson (1973, Perception and Psychophysics, 14, 3-12). Target interresponse times were 300, 400, 500, 600, and 700 ms, and in all cases interresponse intervals produced by both the old and young adults matched the target times very closely. Wing and Kristofferson's analytical procedure was used to decompose tapping variance into that attributable to timing processes and that resulting from motor implementation of the timing signal. Both sorts of variance increased with increasing target interresponse time (with timer variance increasing most markedly), but no difference was found in either type of variance in comparisons between the old and younger subjects. If the internal tempo measure directly reflects the speed of internal timing processes, the data suggest that such processes are slower, but not relatively more variable, in older than younger subjects (consistent with some previous evidence and speculation), but that the calibration of performance forced by the synchronization task will make such an age-related difference in "internal clock speed" unobservable on synchronized-tapping tasks.
A time projection chamber (TPC) is a strong candidate for the central tracker of the international linear collider (ILC) experiment and we have been conducting a series of cosmic ray experiments ...under a magnetic field up to 4T, using a small prototype TPC with a replaceable readout device: multi-wire proportional chamber (MWPC) or gas electron multiplier (GEM). We first confirmed that the MWPC readout could not be a fall-back option of the ILC-TPC under a strong axial magnetic field of 4T since its spatial resolution suffered severely from the so called E×B effect in the vicinity of the wire planes. The GEM readout, on the other hand, was found to be virtually free from the E×B effect and gave the resolution determined by the transverse diffusion of the drift electrons (diffusion limited). Furthermore, GEMs allow a wider choice of gas mixtures than MWPCs. Among the gases we tried so far a mixture of Ar–CF4-isobutane seems promising as the operating gas of the ILC-TPC because of its small diffusion constant especially under a strong magnetic field. We report the spatial resolution obtained with the GEM readout in this gas mixture. Also presented is the spatial resolution of a GEM-based ILC-TPC estimated from the measurement with the prototype.
INDRA, a 4π charged product detection array at GANIL Pouthas, J.; Borderie, B.; Dayras, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/1995, Volume:
357, Issue:
2
Journal Article
Peer reviewed
INDRA, a new and innovative highly segmented detector for light charged particles and fragments is described. It covers geometrically 90% of the 4π solid angle and has very low detection thresholds. ...The detector, operated under vacuum, is axially symmetric and segmented in 336 independent cells allowing efficient detection of high multiplicity events. Nucleus identification down to very low energy threshold (≈ 1 A MeV) is achieved by using ionization chambers operated with low pressure C
3F
8 gas. Residual energies are measured by a combination of silicon (300 μm thick) and cesium iodide (5 to 14 cm in length) detectors. Very forward angles are covered by fast counting phoswich scintillators (NE102/NE115). Charge resolution up to
Z = 50 is achieved on a large energy dynamic range (5000 to 1 for silicon detectors). Isotopic separation is obtained up to
Z = 3. The treatment of the signals is performed through specifically designed and highly integrated modules, most of which are in the new VXIbus standard. Full remote control of parameter settings, including visualization of signals, is thus allowed. The detector is continuously monitored with a laser source and electronic pulsers and is found stable over several days. Energy calibration procedures, making use of specific detectors and the ability of the GANIL accelerator to deliver secondary beams, have been developed. First experiments were performed in the spring of 1993.
MUST: A silicon strip detector array for radioactive beam experiments Blumenfeld, Y; Auger, F; Sauvestre, J.E ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/1999, Volume:
421, Issue:
3
Journal Article
Peer reviewed
A new and innovative array, MUST, based on silicon strip technology and dedicated to the study of reactions induced by radioactive beams on light particles is described. The detector consists of 8 ...silicon strip – Si(Li) telescopes used to identify recoiling light charged particles through time of flight, energy loss and energy measurements and to determine precisely their scattering angle through
X,
Y
position measurements. Each 60×60
mm
2 double sided silicon strip detector with 60 vertical and 60 horizontal strips yields an
X–
Y position resolution of 1
mm, an energy resolution of 50
keV, a time resolution of around 1
ns and a 500
keV energy threshold for protons. The backing Si(Li) detectors stop protons up to 25
MeV with a resolution of approximately 50
keV. CsI crystals read out by photo-diodes which stop protons up to 70
MeV are added to the telescopes for applications where higher energy particles need to be detected. The dedicated electronics in VXIbus standard allow us to house the 968 logic and analog channels of the array in one crate placed adjacent to the reaction chamber and fully remote controlled, including pulse visualization on oscilloscopes. A stand alone data acquisition system devoted to the MUST array has been developed. Isotope identification of light charged particles over the full energy range has been achieved, and the capability of the system to measure angular distributions of states populated in inverse kinematics reactions has been demonstrated.
We conducted a series of beam tests of prototype TPCs for the International Linear Collider (ILC) experiment, equipped with an MWPC, a MicroMEGAS, or GEMs as a readout device. The prototype operated ...successfully in a test beam at KEK under an axial magnetic field of up to 1
T. The analysis of data is now in progress and some of the preliminary results obtained with GEMs and MicroMEGAS are presented along with our interpretation. Also given is the extrapolation of the obtained spatial resolution to that of a large TPC expected as the central tracker of the ILC experiment.
HADES is a versatile magnetic spectrometer aimed at studying dielectron production in pion, proton and heavy-ion-induced collisions. Its main features include a ring imaging gas Cherenkov detector ...for electron-hadron discrimination, a tracking system consisting of a set of 6 superconducting coils producing a toroidal field and drift chambers and a multiplicity and electron trigger array for additional electron-hadron discrimination and event characterization. A two-stage trigger system enhances events containing electrons. The physics program is focused on the investigation of hadron properties in nuclei and in the hot and dense hadronic matter. The detector system is characterized by an 85% azimuthal coverage over a polar angle interval from 18
°
to 85
°
, a single electron efficiency of 50% and a vector meson mass resolution of 2.5%. Identification of pions, kaons and protons is achieved combining time-of-flight and energy loss measurements over a large momentum range ( 0.1 <
p
< 1.0 GeV/
c
. This paper describes the main features and the performance of the detector system.
The central neutron detector for CLAS12 Niccolai, S.; Hull, G.; Bettane, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2018, Volume:
904
Journal Article
Peer reviewed
The Central Neutron Detector, a recently constructed scintillator barrel which is used in CLAS12 at Jefferson Lab to detect 0.2–1 GeV neutrons at backwards angles, is here described. The motivations ...and R&D tests leading to its final design, based on three radial layers of coupled paddles with one-side light readout by photomultipliers plus “U-turn” lightguides on the other side, are outlined. The performance of the detector, evaluated from cosmic-ray tests and simulations, which satisfies the physics requirements, is reported.
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