Cosmic Ray Test Research Articles

Performance of a new LMRPC prototype for the STAR MTD system

A new prototype of a Long-Strip Multi-Gap Resistive Plate Chamber (LMRPC) for the STAR Muon Telescope Detector (MTD) at RHIC has been developed. This prototype has an active area of 52×90 cm 2 and consists of six 250 μm wide gaps. Each detector has 12 strips, read-out at both ends, which are each 3.8 cm wide and 90 cm long with 0.6 cm intervals. In cosmic-ray tests, the efficiency was larger than 95% and the time resolution was ∼75 ps for the 94% Freon, 5% iso-butane, and 1% SF 6 gas mixture. There was good uniformity in the performance across the different strips. The module was also tested in a proton beam at IHEP in Beijing. The efficiency was close to 100% and the best timing resolution achieved was 55 ps for the 90% Freon, 5% iso-butane, and 5% SF 6 gas mixture. Trigger scans along and across the strip direction were also performed.

Cosmic ray tests of a GEM-based TPC prototype operated in Ar–CF 4–isobutane gas mixtures

Argon with an admixture of CF 4 is expected to be a good candidate for the gas mixture to be used for a time projection chamber (TPC) in the future linear collider experiment because of its small transverse diffusion of drift electrons especially under a strong magnetic field. In order to confirm the superiority of this gas mixture over conventional TPC gases we carried out cosmic ray tests using a GEM-based TPC operated mostly in Ar–CF 4–isobutane mixtures under 0–1 T axial magnetic fields. The measured gas properties such as gas gain and transverse diffusion constant as well as the observed spatial resolution are presented.

Cosmic Ray Test for CTOF with Triplet of Prototype Counters Equipped with Fine-Mesh PMTs

Cosmic Ray Test for CTOF with Triplet of Prototype Counters Equipped with Fine-Mesh PMTs

RPC HADES-TOF wall cosmic ray test performance

Abstract In this work we present results concerning the cosmic ray test, prior to the final installation and commissioning of the new Resistive Plate Chamber (RPC) Time of Flight (TOF) wall for the High-Acceptance DiElectron Spectrometer (HADES) at GSI. The TOF wall is composed of six equal sectors, each one constituted by 186 individual 4-gaps glass-aluminium shielded RPC cells distributed in six columns and 31 rows in two partially overlapping layers, covering an area of 1.26 m2. All sectors were tested with the final Front End Electronic (FEE) and Data AcQuisition system (DAQ) together with Low Voltage (LV) and High Voltage (HV) systems. Results confirm a very uniform average system time resolution of 77 ps sigma together with an average multi-hit time resolution of 83 ps. Crosstalk levels below 1% (in average), moderate timing tails along with an average longitudinal position resolution of 8.4 mm sigma are also confirmed.

Pre-installation tests and calibration of the ALICE TOF modules

Before installation into the ALICE experiment, all 87 modules of the TOF system had to undergo a series of tests. Initial check-ups included control of the gas tightness, readout connections quality, and high-voltage tests. Further tests were performed on a specially constructed Cosmic Ray Test Facility, where main characteristics of the modules were scanned under the working high voltage by means of cosmic muons. All TOF channels proved to provide the detection efficiency of more than 97% and time resolution of 80–110 ps, which complies with the ALICE requirements.

Characteristics of the sampling paddle modules of neutron wall from the cosmic ray test

In the construction of a large area neutron detector (neutron wall) that is used to detect neutrons at GeV energies, the performances of all the sampling paddle modules prepared for the neutron wall are investigated with a specially designed test bench. Tested by cosmic rays, an average intrinsic time resolution of 222.5 ps is achieved at the center of the modules. The light attenuation length and the effective speed of the light in the module are also investigated.

Tuning of the cosmic-ray test system of the BESIII drift chamber

The BESIII drift chamber and its subsystems need a cosmic-ray test after the chamber construction to check the chamber construction quality, testing the joint operation of the whole system and the performance of the chamber. The noise performance, drift time and charge measurements, and the scanning of channels were examined specifically. The preliminary results of the test indicate that the whole system works well.

An imaging time-of-propagation system for charged particle identification at a super B factory

Super B factories that will further probe the flavor sector of the Standard Model and physics beyond will demand excellent charged particle identification (PID), particularly K/π separation, for momenta up to 4GeV/c, as well as the ability to operate under beam backgrounds significantly higher than current B factory experiments. We describe an Imaging Time-of-Propagation (iTOP) detector which shows significant potential to meet these requirements. Photons emitted from charged particle interactions in a Cherenkov radiator bar are internally reflected to the end of the bar, where they are collected on a compact image plane using photodetectors with fine spatial segmentation in two dimensions. Precision measurements of photon arrival time are used to enhance the two dimensional imaging, allowing the system to provide excellent PID capabilities within a reduced detector envelope. Results of the ongoing optimization of the geometric and physical properties of such a detector are presented, as well as simulated PID performance. Validation of simulations is being performed using a prototype in a cosmic ray test stand at the University of Hawaii.

The MICE spectrometers for the measurement of muon beam emittance

Tracking detectors based on 350‐μm scintillating fibers have been developed to measure muon-beam emittance at the Muon Ionization Cooling Experiment (MICE), the goal of which is to demonstrate ionization cooling by constructing and testing part of a cooling channel designed for a Neutrino Factory. The upstream and downstream trackers were assembled at the Rutherford Appleton Laboratory (RAL) in 2008 and 2009. The mechanical design and construction (including quality assurance) procedures used for the trackers are described in this paper. Results from the cosmic-ray test performed for the upstream tracker at RAL in 2008 are also presented.

First test results from a Micromegas large TPC prototype

Beam and cosmic-ray tests of a Micromegas Large Prototype TPC for the International Linear Collider are being carried out at DESY in the PC-MAG magnet. Data have been taken with standard anode pads and also with a resistive anode. Results on the resolution performance and operation conditions are given.

Design and construction of the BESIII detector

This paper will discuss the design and construction of BESIII, which is designed to study physics in the τ-charm energy region utilizing the new high luminosity BEPCII double ring e +e − collider. The expected performance will be given based on Monte Carlo simulations and results of cosmic ray and beam tests. In BESIII, tracking and momentum measurements for charged particles are made by a cylindrical multilayer drift chamber in a 1 T superconducting solenoid. Charged particles are identified with a time-of-flight system based on plastic scintillators in conjunction with dE/dx (energy loss per unit pathlength) measurements in the drift chamber. Energies of electromagnetic showers are measured by a CsI(Tl) crystal calorimeter located inside the solenoid magnet. Muons are identified by arrays of resistive plate chambers in a steel magnetic yoke for the flux return. The level 1 trigger system, data acquisition system and the detector control system based on networked computers will also be described.

Studies of timing properties for a TOF counter at an external target facility

Timing and amplitude properties of a prototype scintillator TOF counter at an external target facility are studied with a cosmic rays test. The dependence of signal pulse height and time resolution on the coordinate along the scintillator TOF counter is investigated with two different discriminators. A time resolution of 165 ps can be achieved at the center of the counter with a constant fraction discriminator. Time resolution better than 150 ps is obtained at the center with a leading edge discriminator after time walk correction is applied for off-line analysis.

Study of the RPC-Gd as thermal neutron detector

The BESIII RPC with Gd coating as thermal neutron detector was designed and constructed. Three prototypes were built with different techniques of producing the gadolinium converter. The performance of the cosmic ray test, the signal and the radiation spectrum were discussed in this paper. Lastly, the efficiency of one prototype with the best performance for detecting the thermal neutron was tested as 8.7%.

Perspectives of a mid-rapidity dimuon program at the RHIC: a novel and compact muon telescope detector

We propose a large-area, cost-effective muon telescope detector (MTD) at mid-rapidity for the solenoidal tracker at the RHIC (STAR) and for the next generation of detectors at a possible electron–ion collider. We utilize large multi-gap resistive plate chambers with long readout strips (long-MRPC) in the detector design. The results from cosmic ray and beam tests show that the intrinsic timing and spatial resolution for a long-MRPC are 60–70 ps and ∼1 cm, respectively. The performance of the prototype muon telescope detector at STAR indicates that muon identification at a transverse momentum of a few GeV/c can be achieved by combining information from track matching with the MTD, ionization energy loss in the time projection chamber and time-of-flight measurements. A primary muon over secondary muon ratio of better than 1/3 can be achieved. This provides a promising device for future quarkonium programs and primordial dilepton measurements at the RHIC. Simulations of the muon efficiency, the signal-to-background ratio of J/ψ, the separation of ϒ 1S from 2S+3S states and the electron–muon correlation from charm pair production in the RHIC environment are presented.

The TOTEM T2 telescope based on triple-GEM chambers

The TOTEM experiment at LHC has chosen the triple Gas Electron Multiplier (GEM) technology for its T2 telescope which will provide charged track reconstruction in the pseudorapidity range 5.3 < | η | < 6.5 and a fully inclusive trigger for inelastic events. GEMs are gas filled detectors which combine good spatial resolution with very high rate capability and a good resistance to radiation. Preliminary results of cosmic ray tests performed at CERN on final T2 modules before installation are here presented. Comparisons between real and simulated detector performance are also shown.

Long-term operation of a multi-channel cosmic muon system based on scintillation counters with MRS APD light readout

A Cosmic Ray Test Facility (CRTF) is the first large-scale implementation of a scintillation triggering system based on a new technique, scintillation tile with MRS APD light readout (START). In START, the scintillation light is collected and transported by WLS optical fibers, while light detection is performed by pairs of avalanche photodiodes with the Metal–Resistor–Semiconductor structure (MRS APD) operated in the Geiger mode. START delivers 100% efficiency of cosmic muon detection, while its intrinsic noise level is less than 10 - 2 Hz . CRTF, consisting of 160 START channels, has been continuously operated by the ALICE TOF collaboration for more than 25 000 h, and has demonstrated a high level of stability. Fewer than 10% of MRS APDs had to be replaced during this period.

Measurement of Cherenkov photons by SiPMs with light guides

Silicon Photomultipliers (SiPMs) are attractive photon detectors for Ring Imaging Cherenkov (RICH) counters inside large magnetic spectrometers due to their insensitivity to magnetic fields. We have investigated the possibilities offered by these new photon detectors in a cosmic ray test set-up. Cherenkov photons emitted by cosmic ray particles in an aerogel radiator have been detected with silicon photomultipliers for the first time. Estimates and tests show how light concentrators may improve the detection efficiency, thus showing promise for a SiPM based RICH detector. The optimum shape for these light guides is investigated.

Construction and Performance of a High Granularity Calorimeter

We describe the realization and performance of a prototype high granularity calorimeter built with lead and scintillating fibers. We describe the calorimeter construction and show cosmic ray and electron test beam results obtained with a custom-designed trigger.

Design and test of a Multi-gap Resistive Plate Chamber with Long readout-strip (LMRPC)

A new kind (two end readout) of Multi-gap Resistive Plate Chamber with long readout-strip (LMRPC) is developed to be used at the large-area Muon Telescope Detector (MTD) at mid-rapidity at RHIC/STAR experiment for Time-of-Flight (TOF) measurement. The LMRPC has an active area of 87 cm × 17 cm, 10 gas gaps of 250 μm arranged in 2 stacks, with readout strips of 2.5 cm wide and 90 cm long. The considerations in LMRPC design related to its performance are discussed in this paper. The cosmic ray test results of a prototype LMRPC show a detection efficiency >95% and the time resolution ∼70 ps.

ATLAS RPC certification with cosmic rays

Almost one-third of the 1116 resistive plate chamber (RPC) units installed in the ATLAS experiment was tested and certified at the Lecce Cosmic Ray Testing Facility. About half of these units belong to the same chamber typology named barrel outer small (BOS). This large and nearly homogeneous sample allowed to perform an extensive study of the detector behavior and characteristics. The intrinsic spread of the chamber parameters was extracted after correction for known pressure and temperature effects. A residual dependence on pressure and temperature has been found and empirically corrected. The distribution of gas gap and panel efficiencies, cluster sizes (CSs), single rates and dark currents versus the applied threshold and high voltage was measured. An optimal working point was defined for each gas volume and the distribution of all relevant parameters was studied at the average working point for different voltage threshold. This work shows that the single unit BOS ATLAS RPC meets the experiment requirements.