Submit to QuBS Review for QuBS

Journal Menu

Journal Browser

► Journal Browser

Quantum Beam Sci., Volume 10, Issue 1 (March 2026) – 5 articles

Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
You may sign up for e-mail alerts to receive table of contents of newly released issues.
PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.

Order results

Result details

Section

Show export options Show export options

Select all

Export citation of selected articles as:

17 pages, 3608 KB

Open AccessReview

Optimized Neutronics Designs of the Indonesian Experimental Power Reactor/RDE (Comprehensive Review and Future Challenges)

by Peng Hong Liem

Quantum Beam Sci. 2026, 10(1), 5; https://doi.org/10.3390/qubs10010005 - 2 Feb 2026

Abstract

In this paper, several optimized design results of the HTGR-based 10 MWth Reaktor Daya Eksperimental (RDE) (Experimental Power Reactor), so far conducted, are reviewed and compared from the neutronics, reactor types, refueling schemes, and fuel cycle points of view. The review covers the multipass and once-through-then-out (OTTO) pebble-bed cores, as well as block/prismatic type cores with several fuel shuffling options. As for the fuel cycle, uranium and thorium fuels are considered. The fuel burnup performance and power distribution are evaluated and compared among other important design parameters. Reactor physics codes, nuclear data libraries, and calculation models and procedures used for the design and analysis are reviewed, and challenges for future improvements are discussed. Full article

(This article belongs to the Section Instrumentation and Facilities)

► Show Figures

Figure 1

10 pages, 5092 KB

Open AccessFeature PaperArticle

A Compact Heat Sink Compatible with a Ka-Band Gyro-TWT with Non-Superconducting Magnets

by Shaohang Ji, Boxin Dai, Zewei Wu, Wei Jiang, Xin Chen, Binyang Han, Jianwei Zhou, Qianqian Chen, Guo Liu, Yelei Yao, Jianxun Wang and Yong Luo

Quantum Beam Sci. 2026, 10(1), 4; https://doi.org/10.3390/qubs10010004 - 22 Jan 2026

Viewed by 61

Abstract

This paper presents a thermal management solution for a Ka-band gyrotron traveling wave tube (gyro-TWT) with non-superconducting magnets. At present, the miniaturization and non-superconductivity of gyro-TWT have become a trend, but miniaturization leads to a significant increase in power density and a severe limitation in heat sink volume, which critically limits power capacity. To address this challenge, a joint microwave–thermal management evaluation model is used to investigate the heat transfer process and identify the crucial factors constraining the power capacity. A cylindrical heat sink with narrow rectangular grooves is introduced. Based on this, the cooling efficiency has been enhanced through structural optimization. The beam–wave interaction, electrothermal conversion, and heat conduction processes of the interaction circuit are analyzed. The compact heat sink achieves a 1.2-fold increase in coolant utilization and reduces the overall volume by 27.4%. Meanwhile, this heat sink improves the cooling performance and power capability of the gyro-TWT effectively. At 29 GHz, the gyro-TWT achieves a pulse power of 150 kW. Simulation results show that the maximum temperature is 348 °C at a 45% duty cycle, reduced by 159 °C. The power capacity of the Ka-band gyro-TWT increases by 40.6%. Full article

(This article belongs to the Section Radiation Scattering Fundamentals and Theory)

► Show Figures

Figure 1

22 pages, 1849 KB

Open AccessReview

Key Considerations for Treatment Planning System Development in Electron and Proton FLASH Radiotherapy

by Chang Cheng, Gaolong Zhang, Nan Li, Xinyu Hu, Zhen Huang, Xiaoyu Xu, Shouping Xu and Weiwei Qu

Quantum Beam Sci. 2026, 10(1), 3; https://doi.org/10.3390/qubs10010003 - 8 Jan 2026

Viewed by 404

Abstract

The global cancer burden continues to increase worldwide. Among the various treatment options, radiotherapy (RT), which employs high-energy ionizing radiation to destroy cancer cells, is one of the primary modalities for cancer. However, increasing the absorbed dose to the target volume also increases the risk of damage to surrounding healthy tissues. This radiation-induced toxicity to normal tissues limits the desirable dosage that can be delivered to the tumor, thereby constraining the effectiveness of radiation therapy in achieving tumor control. FLASH radiotherapy (FLASH-RT) has emerged as a promising technique due to its biological advantages. FLASH-RT involves the delivery of radiation at an ultra-high dose rate (≥40 Gy/s). Unlike conventional RT, FLASH-RT achieves comparable tumor control rates while significantly reducing damage to surrounding normal tissues, a phenomenon known as the FLASH effect. Although the mechanism behind the FLASH effect is not fully understood, this approach shows considerable promise for future cancer treatment. The development of specialized treatment planning systems (TPS) becomes imperative to facilitate the clinical implementation of FLASH-RT from experimental studies. These systems must account for the unique characteristics of FLASH-RT, including ultra-high dose rate delivery and its distinctive radiobiological effects. Critical reassessment and optimization of treatment planning protocols are essential to fully leverage the therapeutic potential of the FLASH effect. This review examines key considerations for the TPS development of electron and proton FLASH-RT, including electron and proton FLASH techniques, biological models, crucial beam parameters, and dosimetry, providing essential insights for optimizing TPS and advancing the clinical implementation of this promising therapeutic modality. Full article

(This article belongs to the Section Medical and Biological Applications)

► Show Figures

Figure 1

14 pages, 2516 KB

Open AccessArticle

Temperature and Fluence Dependence Investigation of the Defect Evolution Characteristics of GaN Single Crystals Under Radiation with Ion Beam-Induced Luminescence

by Xue Peng, Wenli Jiang, Ruotong Chang, Hongtao Hu, Shasha Lv, Xiao Ouyang and Menglin Qiu

Quantum Beam Sci. 2026, 10(1), 2; https://doi.org/10.3390/qubs10010002 - 4 Jan 2026

Viewed by 200

Abstract

To investigate the in situ irradiation effects of gallium nitride at varying temperatures, we combined ion beam-induced luminescence spectroscopy with variable-temperature irradiation using a home-built IBIL system and a GIC4117 2 × 1.7 MV tandem accelerator. Unlike previous static studies—limited to post-irradiation or single-temperature luminescence—we in situ tracked dynamic luminescence changes throughout irradiation, directly capturing the real-time responses of luminescent centers to coupled temperature-dose variations—a rare capability in prior work. To clarify how irradiation and temperature affect the luminescent centers of GaN, we integrated density functional theory (DFT) calculations with literature analysis, then resolved the yellow luminescence band into three emission centers via Gaussian deconvolution: 1.78 eV associated with C/O impurities, 1.94 eV linked to VGa, and 2.2 eV corresponding to CN defects. Using a single-exponential decay model, we further quantified the temperature- and dose-dependent decay rates of these centers under dual-variable temperature and dose conditions. Experimental results show that low-temperature irradiation such as at 100 K suppresses the migration and recombination of V_Ga/C_N point defects, significantly enhancing the radiation tolerance of the 1.94 eV and 2.2 eV emission centers; meanwhile, it reduces non-radiative recombination center density, stabilizing free excitons and donor-bound excitons, thereby improving near-band-edge emission center resistance. Notably, the 1.94 eV emission center linked to gallium vacancies exhibits superior cryogenic radiation tolerance due to slower defect migration and more stable free exciton/donor-bound exciton states. Collectively, these findings reveal a synergistic regulation mechanism of temperature and radiation fluence on defect stability, addressing a key gap in static studies, providing a basis for understanding degradation mechanisms of gallium nitride-based devices under actual operating conditions (coexisting temperature fluctuations and continuous radiation), and offering theoretical/experimental support for optimizing radiation-hardened gallium nitride devices for extreme environments such as space or nuclear applications. Full article

(This article belongs to the Special Issue Quantum Beam Science: Feature Papers 2025)

► Show Figures

Figure 1

12 pages, 1690 KB

Open AccessArticle

Fast and Accurate Pixel Calibration of Tof Neutron Diffractometers with Machine Learning

by Albert P. Song and Ke An

Quantum Beam Sci. 2026, 10(1), 1; https://doi.org/10.3390/qubs10010001 - 25 Dec 2025

Viewed by 728

Abstract

At a spallation neutron source, neutron pulses of varying energies are generated, and the detection of neutrons by instrument detectors is recorded as time-of-flight from the emission of the neutron pulse to its arrival at specific detector pixels with high time resolution. The flight path of neutrons from the moderator to the sample and then to the detector must be precisely calibrated at the detector-pixel level using standard powders, so the neutron events from all pixels can be time-focused to produce high-resolution diffraction patterns. Modern time-of-flight neutron diffractometers at spallation neutron sources are equipped with two-dimensional detectors with millimeter-scale pixelations. The number of pixels in a diffraction instrument can reach millions, which makes a single-pixel-level calibration process time-consuming or even impossible with conventional refinement or fitting approaches. Here we present a machine-learning-aided calibration process using a train-and-predict approach, in which machine learning models are trained on the relationship between an individual pixel time-of-flight diffraction pattern and its diffraction constant. These models use a portion of the available pixels for training, and a good model then predicts the diffraction constants precisely and rapidly for large sets of pixel diffraction patterns. Full article

(This article belongs to the Section Instrumentation and Facilities)

► Show Figures