Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2409.20214

Nuclear fuel imaging using position-sensitive detectors

Santeri Saariokari·Peter Dendooven·Mounia Laassiri·Erik Brücken
View original source ↗Read source document ↗Export metadata ↓

Abstract

We are evaluating the performance of a Passive Gamma Emission Tomography (PGET) device equipped with 3D position-sensitive cadmium zinc telluride (CZT) gamma-ray detectors when used for inspecting spent nuclear fuel assemblies (SFAs). Recent advancements in imaging detector technology may offer a method to extend the capabilities of such devices beyond standard safeguards applications, allowing an efficient non-invasive way to accurately characterise the properties of nuclear fuel assemblies. The efficiency of the currently used small CZT detectors is restricted by the limited likelihood of full gamma-ray absorption, which is needed for optimal imaging information. Employing larger CZT detectors would increase the probability of capturing the full energy of gamma rays, thereby enhancing the sensitivity of the PGET device and the quality of the reconstructed images. Large CZT detectors need to be position-sensitive to determine through which collimator slit a gamma ray travelled. Position sensitivity results from the pixelated readout of the CZT crystals. Pixelation potentially increases the spatial resolution of the system, which is currently determined by the collimator used. Pixelation allows resolving the position of arrival up to (readout pitch)/$\sqrt{12}$. We are additionally exploring the potential of utilising Compton imaging to provide information on the origin of gamma rays along the SFA. A simulation is created using Geant4 to compare the full photon absorption efficiency of large and current, small, crystals. Gamma rays of energy 661.7 keV and 1274 keV are targeted to the model describing the approved apparatus now equipped with 22 mm x 22 mm x 10 mm crystals of CZT. It is observed that the efficiency for photon absorption in this case is greatly increased when compared to the existing detectors.

Explore related subjects

physics.ins-det

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Santeri Saariokari, Peter Dendooven, Mounia Laassiri, Erik Brücken. 2024-09-30. Nuclear fuel imaging using position-sensitive detectors. https://arxiv.org/abs/2409.20214

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

High-Speed Semi-FE Readout Module for ATLAS MDT at HL-LHC: Design and Production-Level Characterization

The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) introduces increased demands on the ATLAS Muon Spectrometer, particularly in terms of data throughput, timing distribution and system reliability. The Phase-II Chamber Service Module (CSM) is a key component of the upgraded Monitored Drift Tube (MDT) trigger and readout system, providing a high-speed interface between the front-end electronics and the backend systems. This paper describes the design and implementation of the Phase-II CSM, together with its validation. The results show that the CSM supports two independent optical uplinks, each operating at a line rate of 10.24 Gbps, together with clock distribution and slow control in the expected operating environment. Integration with small-diameter MDT (sMDT) chambers and tests with the prototype L0MDT trigger system are also presented. The CSM boards are now in production and will be used for installation and integration during the upcoming LHC Long Shutdown.

physics.ins-det↗
arXiv2026

Spectral Discrimination of Deposited Gamma-Ray Energies in a Simulated CeBr$_3$ Scintillator

We show that wavelength measurements of individual detected optical photons may provide additional information about gamma-ray energy deposited in a CeBr$_3$ crystal when the detected-photon-count distributions overlap for nearby gamma-ray energies. Monoenergetic 662 and 629 keV gammas are used in a Geant4 simulation of a $25\times25\times20~\mathrm{mm^3}$ CeBr$_3$ crystal. Assuming a light yield of $6.0\times10^4$ photons/MeV, a wavelength-independent photon-detection efficiency of 30%, and a wavelength resolution of $\sigma_{\lambda}=40$ nm, we find that the fraction of photons reconstructed above 385 nm gives an event-level separation of $\sim$ 2 standard deviations between the 662 and 629 keV event populations selected within the same $\sim$ 1%-wide detected-photon-count interval. No timing or reconstructed interaction-position information is used. The result demonstrates, within the present simulation model, that event-dependent optical spectra can retain energy information beyond an undifferentiated photon count.

physics.ins-det↗
arXiv2026

Operation of a negative ion gas time projection chamber without electronegative fill gases

The high fidelity reconstruction of particle tracks in micropatterned gaseous time projection chambers renders this technology ideal for future rare-event searches, including direction-sensitive dark matter experiments. Large drift distances are typically required for such experiments, so that the overall spatial resolution is limited by diffusion. Negative ion drift exhibits lower diffusion than electron drift and is thus an attractive option for realising a large-scale detector. The use of electronegative gases to create negative ions introduces technical challenges, most notably a reduction in gain when compared to conventional gas mixtures. In this study, we demonstrate a new method for negative ion generation via dissociative electron attachment using the conventional molecular fill gas CF$_4$. Our optical measurements of negative ion drift indicate electron attachment lengths of $<$1 mm and comparable gain to electron avalanches. The individual negative ion avalanches were also time-resolved, allowing the number of ions reaching the readout to be counted. We measure an improved energy resolution by single ion counting, relative to an integrated electron avalanche signal measured under identical gain conditions.

physics.ins-det↗