Energy Resolution Of Detector Research Articles

High-energy-resolution passivated implanted planar silicon detectors

Abstract An alpha particle detector with high energy resolution is highly desired in the fundamental field of high-energy physics and various applications of environmental monitoring. In this paper, an excellent energy resolution of 0.35% for 5486 keV α-particles from 241Am with charge collection efficiency of 98.5% is achieved by a passivated implanted planar silicon detector with the window area of 530 mm². High energy resolution is attributed to high crystalline quality with long carrier lifetime, indicating less scattering of charges by defects and suppression of randomness of signal amplitude distribution. Enhanced energy resolution of radiation detectors will substantially reinforce the exploration within the realm of basic physics and augment the capabilities pertaining to biomedical drug development.

Upgrade of the CMS Electromagnetic Calorimeter for High-Luminosity LHC

The CMS Electromagnetic Calorimeter (ECAL) is a homogeneous PbWO4-based detector. The upcoming High-Luminosity upgrade of the CERN LHC will provide detectors with unprecedented instantaneous luminosity, entailing an increase of the average number of proton-proton collisions per bunch crossing up to a value of 200. To cope with such busy environment and with the trigger latency and rate, the ECAL readout and trigger electronics system will be replaced. The front-end electronics will deploy custom ASICs optimised for precise timing, improved signal discrimination, lossless data compression, and fast transmission. Off-detector FPGA processor boards will form trigger primitives and perform basic signal reconstruction. The upgraded system has been validated over several test beam campaigns. In terms of physics performance, it will match the outstanding energy resolution of the current ECAL detector, while significantly enhancing the time resolution of electrons and photons above 50 GeV.

Improving Energy Resolution of CdSe-Based γ-Ray Detectors through Asymmetric Schottky Contact Engineering Using Oxygen Plasma Treatment.

When creating a Schottky contact to suppress the leakage current of semiconductor γ-ray detectors and improve their energy resolution, it is successfully employed the fact that the formation of a Schottky barrier is determined not only by the difference in the electrode and semiconductor work functions but also affected by the semiconductor surface state. Oxygen plasma (OP) treatment has been used to modify the surface states of CdSe single crystals (SCs) prior to the Au electrode deposition, thereby creating a Schottky contact at the metal-semiconductor interface. The n-type Schottky contact formation has been confirmed by the I-V characteristics and ultraviolet photoelectron spectroscopy analysis. X-ray photoelectron spectroscopy has shown that the stoichiometric state of the CdSe SC surface changes from a Cd-deficient (untreated surface) to a near-ideal stoichiometric (OP-treated surface). In addition, a newly formed CdSeO3 component has been revealed, which is beneficial for suppressing the surface leakage current. The Au/CdSe/Au radiation detector with the single-sided OP-treated surface (Schottky diode) exhibits a higher energy resolution of (23.93 ± 0.89)% for 241Am 59.5 keV γ-rays compared to that of the detectors without surface treatment ((44.66 ± 2.25)%). The energy resolution of the champion CdSe-based Schottky diode type γ-ray detector for 241Am 59.5 keV γ-rays can reach 22.72%.

Unlocking Discovery Potential for Decaying Dark Matter and Faint X-Ray Sources with XRISM

Astrophysical emission lines arising from particle decays can offer unique insights into the nature of dark matter (DM). Using dedicated simulations with background and foreground modeling, we comprehensively demonstrate that the recently launched X-Ray Imaging and Spectroscopy Mission (XRISM) space telescope with powerful X-ray spectroscopy capabilities is particularly well suited to probe decaying DM, such as sterile neutrinos and axion-like particles, in the mass range of a few to tens of keV. We analyze and map XRISM’s DM discovery potential parameter space by considering the Milky Way Galactic DM halo, including establishing an optimal line-of-sight search, as well as dwarf galaxies, where we identify Segue 1 as a remarkably promising target. We demonstrate that with only 100 ks exposure, the XRISM/Resolve instrument is capable of probing the underexplored DM parameter window around a few keV and testing DM couplings with a sensitivity that exceeds by two orders existing Segue 1 limits. Further, we demonstrate that XRISM/Xtend instrument sensitivity enables discovery of the nature of faint astrophysical X-ray sources, especially in Segue 1, which could shed light on star formation history. We discuss implications for decaying DM searches with improved detector energy resolution in future experiments.

Effect of NO annealing on radiation detection performance of Ni/SiO2/4H-SiC MOS capacitors

In this study, Ni/SiO2/4H-SiC metal-oxide-semiconductor (MOS) devices were fabricated, achieving high-energy resolution for alpha particle radiation detection. The SiO2/4H-SiC interface was treated with two different methods: i) annealing in N2 environment, ii) annealing in NO environment. Devices manufactured using the former method show lower dark currents than the latter. This difference is due to a decrease in trap density at the SiO2/4H-SiC interface caused by NO annealing, resulting in a higher barrier height for the device. The NO-30 exhibited a much higher energy resolution of 0.46%@5486 keV compared to 0.95%@5486 keV observed in N2-30, despite both devices exhibiting good energy linearity in response to alpha particles. The SiO2/4H-SiC interface trap density revealed a significant decrease after NO treatment, indicating NO treatment can effectively improve the electrical performance of 4H-SiC MOS devices. CCE analysis showed the NO-30 had a lower surface recombination field (13000 V/cm) compared to N2-30 (35000 V/cm), which improved the charge collection efficiency and energy resolution. This study provides a practical approach for enhancing the energy resolution of 4H-SiC MOS detectors.

Data analysis procedures to improve energy resolution in silicon detectors using GET electronics

This study primarily focuses on improving the energy resolution of Double-Sided Silicon Strip Detectors (DSSSD) through optimized data analysis procedures using General Electronics for Time Projection Chambers (GET). We introduce two edge identification algorithms that demonstrate comparable efficacy. These methods are subsequently integrated with various techniques for measuring pulse amplitude, including sample smoothing and pole-zero cancellation. Notably, sample smoothing significantly enhances performances, achieving a resolution of 0.33% with DSSSD α calibration data. Additionally, we describe and apply the trapezoidal filter, examining its impact on resolution improvement and obtaining comparable results. The study also evaluates how internal GET parameters, specifically the sampling frequency and the shaping time of the Sallen-Key (SK) low-pass filter, affect signal resolution. Higher sampling frequencies and lower values of the SK filter were found to increase performance.

Microstructure evolution of CdZnTe crystals irradiated by heavy ions

Consideration of irradiation effects is important for in-orbit operation and radiation protection in aerospace applications. The configuration of irradiation defects and their impact on deteriorating the carrier transport properties of CZT crystals need to be clarified. In this study, the microdefect evolution mechanism of CdZnTe (CZT) crystals under 10 MeV Chlorine (Cl) ion irradiation at flux of 1×1010∼1×1012 n·cm-2 are investigated. The stacking faults first appear in the CZT crystal at 4.5×10-4 displacement per atom (dpa), which are categorized into slip-type, gap-type and vacancy-type. In order to hinder the further expansion of stacking fault, S-shaped stacking fault dipole appears. When the dpa reaches 4.5×10-2, the local phase transition occurs in the damage zone to form CuPt-A ordered phase with ZnTe/CdTe periodic arrangement because the fluctuation in local composition and strain caused by cascade collisions. The deterioration of electric field distribution and charge collection caused by irradiation damage layer leads to the decrease of γ-ray detection ability. The energy resolution (ER) of the CZT detector for γ-ray can be maintained at 30.6% when the ion flux accumulates to 1×1012 n·cm-2, revealing high irradiation hardness. Consequently, these findings provide a theoretical basis for the radiation damage recovery of CZT detectors, further demonstrating that CZT crystals are the most competitive new generation of room-temperature nuclear radiation detection materials, and can provide radiation protection strategies for similar compound semiconductor materials.

Remark on a promising subtraction readout for pixelated CZT detectors

A new method is presented to improve the spectral performance in pixelated CZT detectors which have large ratios of pixel size to thickness. The concept is using the subtraction signal of adjacent pixels to closely emulate the function of coplanar configuration. This short note is devoted to a discussion of this promising way. The principle and associated electronics of subtraction readout are introduced. The feasibility of this method was investigated by using a self-developed simulation platform. The preliminary experimental results showed that this method can significantly improve the energy resolution of pixelated CZT detectors with large ratios of pixel size to thickness.

Sensitivity and energy resolution of the Balqarad clover detector

Abstract This study investigates operational modes and veto techniques using the Balqarad clover system, focusing on energy resolution parameters like Full Width at Half Maximum (FWHM) and Full Width at Tenth Maximum (FWTM). Comparing with the GAMMA-X detector, clover consistently shows lower FWHM values (e.g., 1.08 keV vs. 1.45 keV for 133Ba), highlighting its higher precision. The clover system also achieves lower Minimum Detectable Activity (MDA) values (ranging from 1.19 to 1.56 Bq for 60Co and 137Cs in direct and addback modes), underscoring its enhanced performance compared to literature data. Practical MDA calculations using a reference soil sample reinforce the advantage of addback mode over direct mode in achieving more accurate measurements. These findings stress the critical importance of selecting the right measurement system for precise applications like radiation monitoring and nuclear safety assessments.

Development of a large NaI(Tl) detection system

A large NaI(Tl) detection system was developed to address the increasing demand for high detection efficiency and high energy resolution detectors across various applications. Through Geant4 simulation and experimental research, critical characteristics of the detector prototype were examined, encompassing energy response, energy nonlinearity, and energy resolution. Given the substantial impact of variations in Tl concentration and the complex process of photon propagation on the detection performance of large NaI(Tl) crystals, the detection efficiency and energy resolution with the radioactive source placed at different incident spots were studied to evaluate its spatial response uniformity. The results demonstrate that the detector's energy response range spans from 50 keV to 3 MeV with an energy nonlinearity of 1.5%. The developed large NaI(Tl) detection system achieved an overall energy resolution of 7.93%, along with excellent uniformity in its resolution and detection efficiency, satisfying the application requirements for large dimensions and high detection efficiency.

Deep learning-based gamma spectroscopic analysis considering multiple variables for in situ applications

Gamma spectroscopy in environments with fluctuating temperatures, magnetic fields, and radiation doses can lead to inaccurate material analysis and increased radiation exposure for workers. In this manuscript, we propose a deep learning model that reduces human intervention and remains robust against variables in uncontrolled environments, thereby enhancing the applicability of gamma spectroscopy in the field. The process of establishing a dataset to train, validate, and test the deep learning model involved simultaneous consideration of multiple variables, including gain shifts, detector energy resolutions, the number of mixed radioisotopes (RIs), mixed RI ratios, and statistical fluctuations of the spectrum. The model was trained using multi-label learning to perform RI identification and quantification simultaneously. Specifically, the RI quantification output of our model structure was designed to predict full-energy peak areas and mixed ratios for each RI. Highlighting the importance of a high-performance training dataset, the training and validation results of the gamma spectroscopy model were analyzed in depth. In the test results, organized by RI type and number of mixed RIs, the model demonstrated that following: even under complex conditions with multiple variables, all outcomes for RI identification and quantification were predicted with high accuracy and precision, exceeding 98%.

First application of scintillator-based photon-counting computed tomography to rock samples: Preliminary results and prospects

Abstract Knowledge of the three-dimensional distribution of minerals in a rock sample is of fundamental importance to deciphering a sample’s properties and history. Attenuation-contrast X-ray computed tomography (X-ray CT) is widely used in the geosciences to determine the three-dimensional distributions of minerals or pores, or both. Photon counting CT (PC-CT) uses a novel energy-resolved X-ray detector that allows X-rays with a continuous energy spectrum to be detected separately within arbitrary energy ranges. Here we report the first results of applying laboratory-build PC-CT combined with multi-pixel photon counter (MPPC) to common minerals such as quartz and calcite. In the low-energy range, PC-CT produced higher contrast images than single-energy X-ray CT. Minerals were successfully identified from the relationships between the mean CT values for each energy window and the mean difference between pairs of energy windows. These results suggest that PC-CT can produce high-contrast images of minerals and may be able to distinguish mineral phases with different attenuation curves, even when their CT values are similar. We obtained CT images of minerals in a natural sedimentary rock sample, composed mainly of quartz and carbonate. Although the spatial resolution of the detector in this study was insufficient for the sample, the main carbonate veins were clearly visible as high carbonate-content areas in the PC-CT images. Given some prior knowledge of mineral phases from other methods, it may be possible to use PC-CT imaging to obtain further information about their chemical compositions.

Optimization and experimental validation of deuterium-tritium neutron monoenergetics for diamond detector testing

Diamond detectors are excellent tools for measuring deuterium-tritium (D-T) neutron energy spectra. It has great potential for application in the field of magnetic confinement fusion. However, the current experimental values of the energy resolution of diamond detectors are much lower than the theoretical estimates. The purpose of this study is to find a method for experimental optimization. For this purpose, the D-T neutron energy distribution of the accelerator is theoretically analyzed and simulated. A method to increase the deuteron energy to obtain a better monoenergetic neutron source is proposed. This strategy was validated experimentally. The energy resolution of diamond for D-T neutrons achieves 1.21%, a Full Width at Half Maximum of 93 keV at 7.65 MeV. It is the highest resolution recorded to date. These results demonstrate the feasibility of the optimization method.

Progress toward absolute calibrations of DC x-ray sources from 1keV to >30keV for Z diagnostics applications.

Numerous x-ray diagnostics at the Z facility, time-resolved and time-integrated, would benefit from a local calibrated x-ray source. For many years, Z has used low-power Manson x-ray sources to provide some characterization information for components of Z diagnostics below 30keV. More recently, we have acquired TruFocus x-ray sources, which operate at voltages up to 100kV depending on the anode material and model. These DC sources have demonstrated good stability and repeatability. Absolute calibrations of either sources or detectors usually involve another calibrated detector from another source, which has not been readily available locally. Therefore, we have adopted the strategy of characterizing a sensitive semiconductor diode detector by controlling or inferring the active volume. This characterized detector is then used to scale the Manson x-ray spectral shape as measured by an Amptek energy-resolving detector. The result agrees well with the modeled source spectrum. We can apply this technique to the TruFocus as well.

Simultaneous imaging and element differentiation by energy-resolved x-ray absorption ghost imaging.

Based on the x-ray absorption edges of different elements, we simultaneously image and distinguish the composition of three differently shaped components of an object by using energy-resolved x-ray absorption ghost imaging (GI). The initial x-ray beam is spatially modulated by a series of Hadamard matrix masks, and the object is composed of three pieces of Mo, Ag, and Sn foil in the shape of a triangle, square, and circle, respectively. The transmitted x-ray intensity is measured by an energy-resolved single-pixel detector with a spectral resolution better than 0.8 keV. Through correlation of the transmission spectra with the corresponding Hadamard patterns, the spectral image of the sample is reconstructed, with a spatial resolution of 108 µm. Our experiment demonstrates a practical application of spectral ghost imaging, which has important potential for the noninvasive analysis of material composition and distribution in biology, medical science, and many other fields.

Response of a high-pressure 4He scintillation detector to nuclear recoils up to 9 MeV

Helium-4-based scintillation detector technology is emerging as a strong alternative to pulse-shape discrimination-capable organic scintillators for fast neutron detection and spectroscopy, particularly in extreme gamma-ray environments. The 4He detector is intrinsically insensitive to gamma radiation, as it has a relatively low cross-section for gamma-ray interactions, and the stopping power of electrons in the 4He medium is low compared to that of 4He recoil nuclei. Consequently, gamma rays can be discriminated by simple energy deposition thresholding instead of the more complex pulse shape analysis. The energy resolution of 4He scintillation detectors has not yet been well-characterized over a broad range of energy depositions, which limits the ability to deconvolve the source spectra. In this work, an experiment was performed to characterize the response of an Arktis S670 4He detector to nuclear recoils up to 9 MeV. The 4He detector was positioned in the center of a semicircular array of organic scintillation detectors operated in coincidence. Deuterium–deuterium and deuterium–tritium neutron generators provided monoenergetic neutrons, yielding geometrically constrained nuclear recoils ranging from 0.0925 to 8.87 MeV. The detector response provides evidence for scintillation linearity beyond the previously reported energy range. The measured response was used to develop an energy resolution function applicable to this energy range for use in high-fidelity detector simulations needed by future applications.

Noise analysis and optical response of microwave kinetic inductance detectors with an optical stack

We report on the experimental investigation of optical coupling for superconducting microresonators known as microwave kinetic inductance detectors (MKIDs) in the visible and near-infrared bands. MKIDs are photon-counting, time and energy-resolving detectors that still suffer from a poor quantum efficiency. To improve this efficiency, we propose to add a superconducting reflective layer below the absorbing part of the detector separated by a transparent Al2O3 layer with a quarter-wavelength thickness optimized around a single wavelength λ = 405 nm. We have first fabricated samples patterned from stoichiometric TiN ( Tc∼4 K), one with the full optical stack, one without for reference and one with a partial optical stack in order to characterize the noise influence of each layer individually. We observe that the full optical stack geometry has the most impact on the resonator’s noise and quality factors. A second design was fabricated to characterize the optical response to short pulses of the optical stack and we show from both the frequential noise and optical response that a strong signature of TLS is still present in the optical stack sample. We have finally obtained single-photon response with the optical stack using a more sensitive tri-layer TiN/Ti/TiN absorber ( Tc∼1.3 K) for which a maximum energy resolving power of R=E/ΔE∼ 1.3 was achieved using 405 nm laser pulses at 225 mK. The quality factors of both the reference and optical stack samples are similar but the frequency noise is still a tenfold higher for the optical stack sample which degrades the energy-resolving power of the detector.

Scientific impact of a noiseless energy-resolving detector for a future exoplanet-imaging mission

Scientific impact of a noiseless energy-resolving detector for a future exoplanet-imaging mission

Feasibility of improving image performance in photon-counting computed tomography using X-ray spectrum filtration

Photon-counting computed tomography (PCCT) is an emerging technology based on new energy-resolving X-ray detectors (photon-counting detectors (PCDs)) that provide promising image performance compared to the conventional energy-integrating CT (EICT). It has the potential to provide higher resolution and contrast, lower radiation dose, and fewer artifacts, which has led to significant research interest. This study proposes a method to further improve the image performance of the PCCT using an X-ray spectrum filtration technique. We conducted a feasibility study via simulations using aluminum (Al), beryllium (Be), sodium (Na), nickel (Ni), tin (Sn), neodymium (Nd), and tantalum (Ta) incorporating varying thicknesses using a PCD simulation toolkit (PcTK). The PCCT system used in this simulation was modeled to have a cadmium telluride-based PCD with four multi-energy thresholds of E = 40, 60, 80, 100 keV, assuming that the object received the same number of photons. Using the PCCT images obtained with the highest threshold (i.e., E4 = 100 keV), the image quality was evaluated quantitatively in terms of the signal difference-to-noise ratio (SDNR) and structural similarity (SSIM). Among the filtrations selected in this simulation, a filtration of 2.0 mmAl (inherent) and 1.5 mmSn (added) showed the best image quality. The SDNR and SSIM values measured in the PCCT image obtained with an added filtration of 1.5 mmSn were 3.73 and 0.81, approximately 1.9 and 1.8 times higher than those with no added filtration, respectively. Consequently, the X-ray spectrum filtration technique in PCCT is useful to further improve image performance.

Development of a dual-mode energy-resolved neutron imaging detector: High spatial resolution and large field of view

Energy-resolved neutron imaging is an effective way to investigate the internal structure and residual stress of materials. Different sample sizes have varying requirements for the detector's imaging field of view (FOV) and spatial resolution. Therefore, a dual-mode energy-resolved neutron imaging detector was developed, which mainly consisted of a neutron scintillator screen, a mirror, imaging lenses, and a time-stamping optical fast camera. This detector could operate in a large FOV mode or a high spatial resolution mode. To evaluate the performance of the detector, the neutron wavelength spectra and the multiple spatial resolution tests were conducted at CSNS. The results demonstrated that the detector accurately measured the neutron wavelength spectra selected by a bandwidth chopper. The best spatial resolution was about 20 μm in high spatial resolution mode after event reconstruction, and a FOV of 45.0 mm × 45.0 mm was obtained in large FOV mode. The feasibility was validated to change the spatial resolution and FOV by replacing the scintillator screen and adjusting the lens magnification.