Cosmic Muon Detection Research Articles

High efficiency muon registration system based on scintillator strips

Experiments such as mu2e (FNAL, USA) and COMET (KEK, Japan) seek the direct muon-to-electron conversion to study Charged Lepton Flavor Violation processes. A highly efficient (up to 99.99% efficiency) cosmic muon detection system is needed to achieve a single-event sensitivity below 10−17. In this article, the possibility of attaining such efficiency in the short and long term is discussed for modules based on 7-mm- or 10-mm-thick and 40-mm-wide plastic scintillation strips with a single 1.2 mm WLS fiber glued into the groove along the strip and using MPPC/SiPM for light detection.A Simplified Light Yield Distribution (SLYD) method to estimate the efficiency of the module is proposed, and the simulation results obtained with GEANT 4 for a system based on a 4-by-4 array of 7x40x3000 mm strips are compared with the experimental data. It is found that for the systems requiring efficiency of 99.99% and higher, it is important to improve the light yield as much as possible and to achieve the smallest possible gap between neighbor scintillation volumes is important.

The JUNO water Cherenkov detector system

The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator detector with the primary physics goal of the neutrino mass ordering determination. The detector will be built in a laboratory 650-m underground. The pool is filled with 34 kton ultrapure water outside the central detector as a water Cherenkov detector for cosmic muon detection. 2400 MCP-PMTs detect the water Cherenkov light produced by cosmic muons. The inner surface of the water veto is covered with a Tyvek reflector to increase the light collection efficiency. A water system is used for water purification and circulation to maintain high water quality for optimal detector performance. A set of radon removal equipment will be integrated with the water system to reduce the radon-induced background in the central detector. Based on prototype studies, the radon concentration in water could be reduced to less than 10 mBq/m3. The cosmic muon detection efficiency of the water Cherenkov detector can reach 99.5%. With this veto system, the cosmic muon-induced fast neutron background can also be reduced to the level of about ∼0.1/day level.

ARIADNE—A novel optical LArTPC: technical design report and initial characterisation using a secondary beam from the CERN PS and cosmic muons

ARIADNE is a 1-ton (330 kg fiducial mass) dual-phase liquid argon (LAr) time projection chamber (TPC) featuring a novel optical readout. Four electron-multiplying charge-coupled device (EMCCD) cameras are mounted externally, and these capture the secondary scintillation light produced in the holes of a thick electron gas multiplier (THGEM) . Track reconstruction using this novel readout approach is demonstrated. Optical readout has the potential to be a cost effective alternative to charge readout in future LArTPCs. In this paper, the technical design of the detector is detailed. Results of mixed particle detection using a secondary beam from the CERN PS (representing the first ever optical images of argon interactions in a dual-phase LArTPC at a beamline) and cosmic muon detection at the University of Liverpool are also presented.

Progress of Veto Detector of JUNO

The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kiloton liquid scintillator detector with neutrino mass hierarchy determination as primary physics goal. The other measurements, including precise neutrino oscillation parameters, solar neutrino, geo-neutrino, supernova neutrinos and the diffuse supernova neutrinos background, will be performed at the same time. The detector will be built in a 700 meter deep underground laboratory. A multi-eto detector, composed of a Top Tracker and a Water Cherenkov, will be installed for cosmic muon detection and background reduction. The Top Tracker detector is placed above the central detector, and is composed of three layers of scintillating strips. The outer part of the Central Detector is filled with water and equipped with about 2400 MCP-PMTs (20 inches) to form the Water Cherenkov detector used for muon tagging. Thanks to the Veto detector, the cosmic muon induced fast neutron background can be reduced to a level of about 0.06/day.

The design of the JUNO veto system

The Jiangmen Underground Neutrino Observatory (JUNO) is a multipurpose 20 kton liquid scintillator detector. The detector will be built in a 700 m deep underground laboratory, and its primary physics goal will be to determine the neutrino mass hierarchy. Due to the low background requirement of the experiment, a multi-veto system for cosmic muon detection and background reduction is designed. The volume outside the central detector is filled with pure water and equipped with 2000 MCP-PMTs (20 inches) to form a water Cherenkov detector for muon tagging. A Top Tracker system will be built by re-using the Target Tracker plastic scintillator modules of the OPERA experiment and will cover half of the top area. This will provide valuable information for cosmic muon induced 9Li/8He study.

Cosmic muon detector using proportional chambers

A set of classical multi-wire proportional chambers was designed and constructed with the main purpose of efficient cosmic muon detection. These detectors are relatively simple to construct, and at the same time are low cost, making them ideal for educational purposes. The detector layers have efficiencies above 99% for minimum ionizing cosmic muons, and their position resolution is about 1 cm, that is, particle trajectories are clearly observable. Visualization of straight tracks is possible using an LED array, with the discriminated and latched signal driving the display. Due to the exceptional operating stability of the chambers, the design can also be used for cosmic muon telescopes.

Cosmic Muon Detection for Geophysical Applications

A portable cosmic muon detector has been developed for environmental, geophysical, or industrial applications. The device is a tracking detector based on the Close Cathode Chamber, an MWPC-like technology, allowing operation in natural underground caves or artificial tunnels, far from laboratory conditions. The compact, low power consumption system with sensitive surface of 0.1 m2measures the angular distribution of cosmic muons with a resolution of 10 mrad, allowing for a detailed mapping of the rock thickness above the muon detector. Demonstration of applicability of the muon telescope (REGARD Muontomograph) for civil engineering and measurements in artificial underground tunnels or caverns are presented.

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.

Prototype of a cosmic muon detection system based on scintillation counters with MRS APD light readout

Scintillation tiles with MRS APD light readout (START) are proposed to be used as basic triggering units of a cosmic muon facility intended for regular tests of all of the numerous ALICE TOF modules in the course of their mass production and exploitation. A prototype 32-channel array of STARTs has been assembled and tested with cosmic rays and beam. With the bias voltage at approximately 50 V, the system has shown operational consistency and homogeneity, almost 100% detection efficiency over the whole surface and intrinsic noise of 10 - 2 Hz per detecting unit. If STARTs are to be mass-produced, the cost of a mosaic array is estimated at a moderate level of 3– 4 kUSD / m 2 .