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Scintillators, Scintillation Detectors

Session chair: Woody , Craig (Brookhaven National Laboratorty, Physics Department, Upton, USA); Kurosawa , Shunsuke (Tohoku University, New Industry Creation Hatchery Cente, Sendai, Japan)
Shortcut: N-12
Date: Wednesday, 20 October, 2021, 7:00 AM - 8:45 AM
Room: NSS - 4
Session type: NSS Session


Click on an contribution to preview the abstract content.

7:00 AM N-12-01

Novel one-sided readout type position-sensitive optical fiber radiation sensor based on the wavelength-resolving analysis (#437)

Y. Terasaka1, 2, K. Watanabe2, 3, A. Uritani2

1 Japan Atomic Energy Agency, Collaborative Laboratories for Advanced Decommissioning Science, Tomioka, Japan
2 Nagoya University, Department of Applied Energy Engineering, Nagoya, Japan
3 Kyushu University, Department of Applied Quantum Physic and Nuclear Engineering, Fukuoka, Japan


A novel one-sided readout type position-sensitive optical fiber radiation sensor was developed. This sensor measures the radiation intensity distribution along the fiber with light readout from only one side of the optical fiber. For the estimation of radiation intensity distribution, the wavelength spectrum at the fiber end, which contains the information of propagation distance of light inside the fiber, was analyzed. Using the unfolding method, radiation intensity distribution along the fiber could be estimated. We have developed two types of sensors, the high dose rate type and the low dose rate type, and demonstrated the position-detection performance of both detectors.

Keywords: Position-sensitive optical fiber, Wavelength spectrum, Spectrum unfolding, Radiation intensity distribution
7:10 AM N-12-02

Growth, scintillation property, and particle identification capability of (Li,Ca)I2 solid solution (#1335)

M. Yoshino1, K. Kamada2, 3, Y. Takizawa1, T. Iida4, K. Mizukoshi5, A. Yoshikawa1, 3

1 Tohoku University, Institute for Materials Research, Sendai, Japan
2 Tohoku University, New Industry Creation Hatchery Center, Sendai, Japan
3 C&A (Crystals and Applications) Corp., Sendai, Japan
4 University of Tsukuba, Faculty of Pure and Applied Science, Tsukuba, Japan
5 Kobe University, Department of Physics, Kobe, Japan


Homeland security, underground physics, and space-based applications often require detecting and identifying both neutron and gamma-ray. Li-containing materials have good thermal neutron detection efficiency through the 6Li(n, α)3H capture reaction, and gamma rejection from neutron signal may be accomplished by pulse shape discrimination. This study reports the pulse shape discrimination capability of (Li,Ca)I2 solid solution scintillators. We evaluate the pulse shape discrimination performance of (Li,Ca)I2 scintillators using F-measure. An excellent F-measure value of 0.998 was obtained for 241Am and 60Co in Li0.1Ca0.9I1.9 sample. The results presented in this paper reveals that  (Li,Ca)I2 scintillator has excellent potential for pulse shape discrimination.

Keywords: Scintillators, Iodine compounds, Gamma-ray effects, Neutron radiation effects
7:20 AM N-12-03

Development of a compact and portable high-sensitivity omnidirectional Compton camera with detector rotation function (#58)

S. Ishikawa1, H. Muraishi1, R. Enomoto2, H. Katagiri3, M. Kagaya4, T. Watanabe5, D. Kano5, S. Nakamura6, Y. Watanabe1, H. Ishiyama1

1 Kitasato University, Sagamihara city, Japan
2 University of Tokyo, Kashiwa city, Japan
3 Ibaraki University, Mito city, Japan
4 National Institute of Technology, Sendai College, Sendai city, Japan
5 National Cancer Center Hospital East, Kashiwa city, Japan
6 National Cancer Center Hospital, Chuo city, Japan


We report the development of a compact and portable high-sensitivity omnidirectional Compton camera in this study. This system can visualise radioactive Cesium with surface or air dose rates of less than 1 μSv/h released by the Fukushima Daiichi Nuclear Power Plant accident, and low-level gamma radiation sources like radioactive contamination and materials in medical facilities. We adopted the Compton camera technology reported in a previous study (Muraishi et al., Jap. J. Appl. Phys. 2020). This technology enables shift-invariant gamma-ray imaging. The detector can be operated from a PC via Wi-Fi at 12 V DC, and 15 W power. Furthermore, by adopting metal package photomultiplier tubes (PMTs) and optimising the crystal arrangement, we miniaturized the detector and improved image quality. The results of outdoor measurements in Fukushima prefecture, Japan, and radioactive material measurements at a boron neutron capture therapy (BNCT) facility using this detector will also be reported.

AcknowledgmentThis study was supported by the Open Source Consortium of Instrumentation (Open-It), Japan, JSPS KAKENHI Grant (No. 15H04769 and 19H04492).
Keywords: Gamma-ray imaging, Compton camera, CsI (Tl), Radioactive cesium, Fukushima Daiichi nuclear powerplant accident
7:30 AM N-12-04

Optimising the Emission Wavelength of Mixed-Halide Perovskite Scintillators (#473)

I. H. B. Braddock1, S. S. Alghamdi1, S. H. Bennett1, C. Crean2, C. L. Grove1, J. G. O'Neill1, C. Shenton-Taylor1, S. J. Sweeney3, 1, M. P. Taggart1, P. J. Sellin1

1 University of Surrey, Department of Physics, Guildford, United Kingdom
2 University of Surrey, Department of Chemistry, Guildford, United Kingdom
3 University of Surrey, Advanced Technology Institute, Guildford, United Kingdom


Lead halide perovskite nanocrystals show promise as scintillators due to their strong X-ray stopping power, bright luminescence, fast response time and low-cost manufacture. In addition to this, it is possible to adjust the luminescence wavelength of the perovskite across the entire visible spectrum. Here, we present nanocrystals with emission wavelengths between 403 and 531 nm, and compare their luminescence and time-response. We also present a nanocomposite scintillator, consisting of perovskite nanocrystals loaded into a 1 cm cube of plastic scintillator. Considering various wavelength-dependent factors such as the quantum efficiency of a PMT, it is then possible to select the optimum nanocrystal for the nanocomposite scintillator detector system. By improving transmission through the composite, the proportion of high-Z perovskite nanocrystals can then be increased, with the aim of producing a plastic scintillator from which photoelectric absorption peaks may be observed.

AcknowledgmentThe project or effort depicted was or is sponsored by the Department of the Defense, Defense Threat Reduction Agency. The content of the information does not necessarily reflect the position or the policy of the federal government, and no official endorsement should be inferred.
Keywords: Scintillator, Plastic Scintillator, Perovskite, Nanocrystal
7:40 AM N-12-05

Neutron Spectroscopy with a Large NaI(Tl+Li) (#512)

A. L. Hutcheson1, R. S. Perea2, B. F. Phlips1

1 U.S. Naval Research Laboratory, Washington, D.C., United States of America
2 National Research Council Research Associate at the U.S. Naval Research Laboratory, Washington, D.C., United States of America


We have characterized the response of a large (28.27 cm x 27.31 cm x 3.81 cm) NaI(Tl+Li) to fast neutrons with a particular focus on its use for neutron spectroscopy. We have performed radiation transport modeling to simulate the response of this detector to monoenergetic neutrons and qualitatively confirmed this response in laboratory with a 252Cf neutron source. Near future (Summer 2021) plans include in-beam neutron measurements to compare more directly to modeled results and to determine the functional relationship between neutron energy and scintillator light output.


This work was sponsored by the Office of Naval Research (ONR) as part of 6.1 funding.

Keywords: neutrons, radiation detectors, scintillation detectors
7:50 AM N-12-06

Breakthrough in Gas Detection: Highlighting the Role of Scintillating Metal-Organic Frameworks (#742)

V. Villemot1, G. H. Bertrand1, M. Hamel1, S. Mauree1, B. Sabot2

1 Université de Paris-Saclay, CEA, LIST, Sensors and Electronics Architectures Laboratory, Gif-sur-Yvette, France
2 Université de Paris-Saclay, CEA, LIST, Henri Becquerel National Laboratory, Gif-sur-Yvette, France


Tritium (3H) is a good tracer of both civil and military nuclear activities such as nuclear reactors and fuel reprocessing plants. However, its detection remains a challenge due to its low energy β- particle. Nowadays, it is mainly performed by offline techniques such as liquid scintillation. Hence, viable alternatives must be studied for its online detection. For this need, scintillating porous materials appear to be a solution with great potential. Indeed, the large specific surface areas and the ability to interact effectively with gases offered by some materials suggest a real interest in creating hybrid materials that serve both as preconcentrating and sensing media. The solution proposed in this work is a metal organic framework (MOF) with photophysical properties suitable with scintillation measurements. In a closed circuit and common activities, it was shown that it is possible to recover photons and attribute them to scintillation event by TDCR method. Based on count rate monitoring, it was shown that an absorption occurs in the material. More interestingly, after the acuum, the count rate does not show a clear inflection, meaning the retention of gas inside the material. These results highlight the use of fluorescent porous materials for gas detection and open new promising applications in nuclear instrumentation.

Keywords: Scintillating Porous Material, Gaz Detection, Tritium
8:00 AM N-12-07

Characterization of scintillating materials in use for brachytherapy fiber based dosimeters (#799)

S. Cometti1, A. Gierej3, T. Baghdasaryan3, J. Van Erps3, F. Berghmans3, A. Giaz1, S. Lomazzi1, R. Santoro1, M. Caccia1, S. O'Keeffe2

1 Università dell'Insubria, DISAT, Como, Italy
2 University of Limerick, Optical Fibre Sensors Research Centre, Limerick, Ireland
3 Brussels Photonics (B-PHOT), Vrije Universiteit Brussel and Flanders Make, Department of Applied Physics and Photonics, Brussels, Belgium

This contribution is submitted on behalf of ORIGIN project.


This paper describes a method to evaluate the light yield and the characteristic decay time of inorganic scintillators used in probes for in vivo brachytherapy dosimeters. The expected scintillating decay time is about hundreds of microseconds and the light emission is diluted in a trail of single photons. As a consequence, the identification of the scintillation occurrence, the estimation of the light yield, and the extraction of the time characteristic are challenging. The results show that the two scintillators have a similar decay time which is of the order of 500 μs while the light yield of the material selected for the low dose rate treatment is almost 4 times higher than the one for the high dose rate therapy.

Keywords: Brachytherapy, Inorganic scintillators, single photoelectron, SiPM
8:10 AM N-12-08

Pulse shape simulations for plastic scintillation detectors using Geant4 (#805)

C. J. Holroyd1, M. Aspinall1, T. Deakin2

1 Lancaster University, Department of Engineering, Lancaster, United Kingdom
2 LabLogic Systems Ltd., Sheffield, United Kingdom


The accurate simulation of the time-dependent pulse shapes from organic scintillation detectors capable of pulse shape discrimination (PSD) presents the opportunity to assess the pulse shape discrimination performance of detectors prior to fabrication. PSD capable plastic scintillators are increasingly replacing organic liquids and crystals for the detection of neutrons in mixed radiation fields for nuclear security applications. Plastics are robust, inexpensive and able to be easily scaled up to larger volumes. However, the PSD performance of plastic scintillators can be unreliable and is known to fluctuate as a result of numerous factors which combine to influence the shape of the output pulse. One such factor is the scintillator geometry, where the ability to separate out neutron and gamma ray induced signals is observed to degrade as the size of the scintillator is increased. This paper describes the use of the Monte Carlo toolkit Geant4 to simulate the time-dependent pulse shapes from a commercially available plastic scintillator. Future work will incorporate the temporal response of the photodetector with existing simulations to improve the accuracy of the simulated pulses and reproduce the exact shape of pulses measured experimentally.

Keywords: Monte Carlo simulations, plastic scintillators, pulse shape discrimination, scintillators
8:20 AM N-12-09

Performance study of plastic scintillators coupled to SiPM for fast-timing measurements (#1022)

J. Benito García1, M. García Díez1, V. Sánchez-Tembleque1, L. M. Fraile Prieto1, J. M. Udias Moinelo1

1 Universidad Complutense de Madrid, Grupo de Física Nuclear, Madrid, Spain


Plastic scintillators are widely used as  beta-particle detectors in nuclear physics. Thin plastics, with thicknesses of few mm, coupled to fast photomultiplier tubes (PMT) are employed for timing measurements. This configuration provides excellent time resolution and homogeneous energy response for a wide range of incident beta particle energies.

On the other hand, silicon photomultipliers (SiPMs) keep gaining relevance due to their compact size, insensitivity to magnetic fields and no need for high voltage supply. Their small size is very attractive for nuclear physics experiments. In the case of plastic fast-timing beta detectors in particular, where most of the space is occupied by the PMT, SiPMs would make it possible to build very compact detectors, provided that they exhibit similar time resolutions. In addition, this would allow to increase the number of detectors, and thus the overall efficiency, while releasing space iin complex setups.

The increased efficiency and flexibility for extended configurations are important points for future measurements at the ISOLDE Decay Station (IDS), where coincidence-delayed βγγ(t) fast-timing experiments are performed. For this purpose, we have tested a new detector based on an EJ-232 scintillator plastic coupled to MICROFJ-SMA-30035-GEVB SiPM from SensL.  Processing the fast signal output of this SiPM we have obtained a time resolution of (155 ps CRT FWHM) against a reference detector. This value is comparable with the one obtained with the same plastic coupled to a fast PMT, which makes this configuration very promising for future experiments.

AcknowledgmentThis work have been supported by EU regional funds (RTC-2015-3772-1, RTC2019-007112-1) Spanish MINECO through projects (FPA2015-65035-P), CAM (S2013/MIT-3024 TOPUS-CM, B2017/BMD-3888 PRONTO-CM) and by EU's H2020 under MediNet a Networking Activity of ENSAR-2 (grant agreement 654002). J.B. acknowledges support from the UCM under Grant No. CT27/16-CT28/16
Keywords: Plastic scintillator, SiPM, PMT, beta detector, fast-timing

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