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Unconventional Detectors

Session chair: Kiselev , Alexander (Brookhaven National Laboratory, Upton, USA); Maehata , Keisuke (Teikyo Univ., Omuta, Japan)
Shortcut: N-33
Date: Friday, 22 October, 2021, 7:00 AM - 8:45 AM
Room: NSS - 3
Session type: NSS Session


Click on an contribution to preview the abstract content.

7:00 AM N-33-01

Q-Pix: Status & Prospects of a Pixelated Readout Concept for large LArTPCs (#971)

K. Nishimura1

1 University of Hawaii, Department of Physics and Astronomy, Honolulu, Hawaii, United States of America

On behalf of the Q-Pix Consortium


Conventional designs for multi-kiloton Liquid Argon Time Projection Chambers (LAr TPCs), such as those being developed for the Deep Underground Neutrino Experiment (DUNE), utilize layers of wires to reduce the number of required readout channels and the corresponding data rate and storage requirements.  
Such 2D readout schemes can suffer from ambiguities that can limit precision of event reconstruction relative to a true 3D readout scheme.  While a pixelated scheme can avoid these ambiguities, novel implementations are required to create a scaleable design that does not grossly exceed power and data rate requirements.  The Q-Pix Consortium, established in 2019, is developing a low-power pixelated readout technique for LAr TPCs based on charge integrate-reset (CIR) circuits.  The CIR blocks generate a sequence of reset pulses with time intervals corresponding to fixed charge integrals, allowing signal reconstruction without continuous digitization.  The Q-Pix ASIC, intended for reading out pixel arrays, comprises CIR blocks along with digital components responsible for communication and reconfigurable data routing.  This contribution will give an overview of the Q-Pix project, its status, and prospects, and update on the development and prototyping of the Q-Pix analog and digital ASIC designs.

Keywords: neutrino, time projection chamber, liquid argon, ASIC
7:15 AM N-33-02

Reconstruction of Inverse Betay Decay events in the SoLid experiment using the ML-EM algorithm (#768)

H. Chanal1

1 Université Clermont Auvergne, CNRS/IN2P3, LPC, Aubière, France

On behalf of the SoLid Collaboration


SoLid is a short-baseline experiment dedicated to the study of the anti-neutrino behaviour. This is a highly segmented detector composed of small PVT cubes (5 cm side) interleaved with 6LiF:ZnS(Ag) screens, and read out by optical fibers and Silicon Photomultipliers (SiPMs). The anti-neutrinos are detected by the Inverse Beta Decay (IBD) process. These events exhibit a specific topology as they produce one positron which annihilates into two gammas. The interaction position and deposited energy of these particles within the detector have to be accurately determined. That will allow to retrieve the signal from the overwhelming backgrounds.

Therefore, we tested different approaches for the event reconstruction. We implemented both the Fast-Iterative Threshold-Shrinkage (FISTA) approach and the Maximum Likelihood Expectation Maximization method (ML-EM). Both are widely used in the medical domain. In this work, we propose an initialisation step to take into account the specificity of the events we are interested in. With it, the ML-EM method exhibits superior performance to FISTA.

Keywords: SoLid, FISTA, ML-EM, Inverse Beta Decay, Anti-neutrino
7:30 AM N-33-03

Purification efficiency and Rn emanation of gas purifiers used with pure and binary gas mixtures for gaseous Dark Matter detectors (#1071)

K. Altenmüller3, J.F. Castel3, S. Cebrián3, T. Dafní3, D. Díez3, J. Galán3, J. Galindo3, J.A. García3, I.G. Irastoza3, I. Katsioulas1, P. Knights1, G. Luzón3, I. Manthos1, C. Margalejo3, J. Matthews3, K. Mavrokoridis2, H. Mirallas3, T. Neep3, K. Nikolopoulos1, L. Obis3, A. Ortiz de Solórzano3, ?. Pérez3, B. Philippou2, R. Ward3

1 University of Birmingham, Particle Physics, Birmingham, United Kingdom
2 University of Liverpool, Particle Physics, Liverpool, United Kingdom
3 University Zaragoza, Particle Physics, Zaragoza, Spain


Rare event searches, such as direct Dark Matter searches, require extreme radiopurity for all components used in a detector. This includes the active medium, which in the case of gaseous detectors, is the target gas. The gases used often include noble gas mixtures with molecular quenchers. In order to achieve the desired detector performance, purification of these gases is required. However, purifiers are known to emanate 222Rn which is a potential source of background for such searches. Several purifiers are studied for their O2 and H2O purification efficiency and Rn emanation rates aiming to identify the lowest-Rn options. Furthermore, the adsorption of quenchers by the purifiers is also assessed when used in single-filling and recirculating closed-loop gas systems.

AcknowledgmentThis project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreements no 841261 (DarkSphere) and no 845168 (neutronSphere).
Keywords: Filtration, Gas Detectors, Radiation Detectors, Radon, Dark Matter
7:45 AM N-33-04

Three dimensional (3D) optical imaging system of muon beams using a ZnS(Ag) sheet combined with a mirror (#481)

S. Yamamoto1, K. Ninomiya2, N. Kawamura3, 4, Y. Hirano1

1 Nagoya University, Graduate School of Medicine, Nagoya, Japan
2 Osaka University, Graduate School of Science, Osaka, Japan
3 KEK, Institute of Materials Structure Science, Tokai, Japan
4 J-PARC Center, Materials and Life Science Division, Tokai, Japan


Optical imaging of muon beam is a promising method for range estimations. However our proposed optical imaging method could only measure two dimensional (2D) projection images. To measure the beam ranges and widths at any position of the muon beam, 3 dimensional (3D) beam distributions are desired. For this purpose, we developed an optical imaging system using a ZnS(Ag) sheet combined with a mirror and cooled charge-coupled device (CCD) camera. ZnS(Ag) sheet was set in a black box and positive muon beam was irradiated to the ZnS(Ag) sheet at J-PARC. The optical image in the ZnS(Ag) sheet was reflected by a surface mirror and images by the  CCD camera during irradiation from the side of the beam. Acrylic plates were set in front of the ZnS(Ag) sheet outside the black box and changed the thickness with 5 mm steps. The measured optical images with different thickness of the acrylic plates were stacked, interpolated to form a 3D optical image and the depth and lateral profiles were evaluated. From the depth profile derived from the 3D images, the Bragg peak position could be estimated. The lateral profiles at Bragg peak could also be derived. We confirmed that 3D optical imaging was possible with the developed system using ZnS(Ag) sheet. The system is promising for measuring the muons beam distribution, research of muons, as well as the future muon radiotherapy.

Keywords: muon, optical imaging, 3D, ZnS
8:00 AM N-33-05

Development of muon scattering tomography for detection of reinforcement in concrete (#694)

M. Dobrowolska1, J. J. Velthuis1, 3, A. Kopp1, C. de Sio1, R. Milne4, P. Pearson4

1 University of Bristol, Physics, Bristol, United Kingdom
2 University of South China, Nuclear Science and Technology, Hengyang, China
3 Cavendish Nuclear, Civil Structural & Architectural Department, Bristol, United Kingdom


Inspection of ageing, reinforced concrete structures is a world-wide challenge. Existing non-destructive evaluation techniques in civil and structural engineering have limited penetration depth and don't allow to precisely ascertain the configuration of reinforcement within large concrete objects. The big challenge for critical infrastructure (bridges, dams, dry docks, nuclear bioshields etc.) is understanding the internal condition of the concrete and steel, not just the location of the reinforcement. In most new constructions the location should be known and recorded in the as-built drawings, where these might not exist due to poor record keeping for older structures. Muon scattering tomography is a non-destructive and non-invasive technique which shows great promise for high-depth 3D concrete imaging. Previously, we have demonstrated that individual bars with a diameter of 33.7±7.3 mm at 50 cm depth can be located using muon scattering tomography. Here we present an improved method that exploits the periodicity of bar structures. With this new method, reinforcement with bars down to 6 mm thickness can be detected and imaged. This allows inspection of all rebar structures inside thick concrete in practical use. This is a very important result for non-destructive evaluation of civil structures.

Keywords: 3D imaging, concrete imaging, reinforcement location, muon scattering tomography, NDE technique
8:15 AM N-33-06

Analytical Muon Scattering Tomography Methods for a Nuclear Waste Imagining Detector (#571)

D. Barker1, A. Alrheli1, C. De Sio2, D. Kikoła3, A. Kopp2, M. Mhaidra2, 3, J. P. Stowell1, L. Thompson1, J. Velthuis2, 4, M. Weekes1

1 University of Sheffield, Department of Physics and Astronomy, Sheffield, United Kingdom
2 University of Bristol, School of Physics, Bristol, United Kingdom
3 Warsaw University of Technology, Warsaw, Poland
4 University of South China, Hengyang, China

As part of the CHANCE project.


An important aspect of nuclear waste management is the ability to effectively characterise unknown objects in order to dispose of the objects safely. To evaluate and compare the current characterisation methods available, the CHANCE (Characterization of conditioned radioactive waste) project has been established. One particular area of interest to the CHANCE project is muon scattering tomography, which has been demonstrated to be an effective, non-invasive technique for the imaging of highly shielded objects. In this presentation, the current status of the CHANCE muon tomography project will be discussed along with an evaluation of the effectiveness of existing analytical reconstruction methods. Furthermore, a new multi-variate analysis approach for locating and identifying objects within nuclear waste drums was developed resulting in a 0.9 (+0.07)(-0.12) positive identification for uranium.


This project has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 755371.

Keywords: Analysis and Statistical Methods, Muon Tomog- raphy, Nuclear Waste, Imaging Techniques
8:30 AM N-33-07

Novel Muon Tomography Detector for the Pyramids (#8)

R. Kouzes1, A. Bonneville1, A. Lintereur2, A. Mahrous4, I. Mostafanezhad3

1 Pacific Northwest National Laboraotry (PNNL), Richland, Washington, United States of America
2 Penn State University, State College, Pennsylvania, United States of America
3 Nalu Scientific, Honolulu, Hawaii, United States of America
4 Egypt-Japan University of Science and Technology, Alexandria, Egypt


Cosmic-ray muons, which impinge upon the Earth’s surface at a rate of approximately 160 muons·m-2·s-1, can be used to image the density of geological and man-made materials located above a muon detector. The detectors used for these measurements must be capable of determining both the muon rate and angle of incidence. Applications of this capability include geological carbon storage, natural gas storage, enhanced oil recovery, compressed air storage, oil and gas production, tunnel detection, and detection of hidden rooms in man-made structures, such as the pyramids. For these applications the detector must be small, rugged, and have operational characteristics which enable use in remote locations, such as low power requirements. A new muon detector design is now being constructed to make measurements on the Khafre pyramid to look for unknown voids that might exist in the structure. The new detector design uses plates of scintillator with fiber optic readout to obtain position information. This design will meet the operational requirements, while also providing a geometry which can be modified for different measurement conditions.

Keywords: muon tomography, scintillators, polyvinyl toluene, PVT, pyramids

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