Single Spectrometer Research Articles

Neutron spectrum measurements inside a self-shielded cyclotron during 18F production using a single-cylindrical neutron spectrometer with gold and indium activation foils

The Single-Cylindrical Neutron Spectrometer (SCNS) is a single moderated spectrometer in the form of a cylinder with a diameter of 8 cm and a length of 16 cm. Seven Au activation foil type neutron detectors are installed on the moderator axis with varying distances. This spectrometer is used to measure the neutron spectrum in self-shielded cyclotron during 18F production using a proton of 11 MeV and a beam current of 25 µA for 70 min. The detector response was calculated using MCNPX 2.7. The measurement results obtained activity of 198Au and 116mIn and were validated with simulation using MCNPX. With the detector response values and detector activity from the measurements, a neutron spectrum was obtained using the unfolding technique using the UMG program. The neutron spectrum from measurements using SCNS with Au and In activation foil detectors has a difference of 8 %. Meanwhile, with the MCNPX calculation results, the measurement results using the Au foil are 1 % while with the In foil it is 10 %.

Stray light analysis and suppression of a UV multiple sub-pupil ultra-spectral imager

A multiple sub-pupil ultra-spectral imager system for simultaneous detection of multiple substances is proposed. By employing pupil separation prisms and grating multilevel spectra, the system achieves simultaneous detection of three spectral channels with a single spectrometer and detector, featuring an ultra-high spectral resolution of 0.1 nm. However, due to simultaneous detection of three channels, the system suffers from significant stray light issues. In response to this problem, a UV multiple sub-pupil ultra-spectral imager system optical-machinery model is constructed in this article. The main sources of stray light are determined through theoretical derivation and simulation analysis, and the level of stray light in the system is analyzed using simulation analysis software. A structure for stray light suppression is optimized, and the use of multispectral filters is proposed to suppress stray light generated by spectral crosstalk in the system. The effectiveness of stray light suppression is evaluated based on the energy response of the receiving surface. The analysis results show that after optimization, the level of stray light in the T1 channel is reduced from 1.4% to 0.65‰, in the T2 channel from 3.0‰ to 0.5‰, and in the T3 channel from 0.16‰ to 0.05‰. Therefore, it can be concluded that the proposed method for stray light suppression in the UV multiple sub-pupil ultra-spectral imager system addressed in this article meets the indicator requirements.

Prediction of interface width in overlap joint configuration for laser welding of aluminum alloy using sensors

We present a method that can predict the interface width in an overlapping joint configuration for laser welding of Al alloys using sensors and a convolutional neural network (CNN)-based deep-learning model. The inputs for multi-input CNN-based deep-learning prediction models are spectral signals, represented by the light intensity measured by a spectrometer and dynamic images of the molten pool filmed by a charge-coupled device (CCD) camera. The interface width, used as learning data for modeling, was constructed as a database along with the process signal by cross-sectional analysis. In this study, we present results showing high accuracy in predicting the interface width in the overlap joint configuration for Al alloy laser welding. For predicting the interface width, five models are created and compared: a single CCD and spectrometer sensor algorithm, a multi-sensor algorithm with two input variables (CCD, spectrometer), a multi-sensor algorithm excluding the processing beam in the spectrometer data on the combination of Al 6014-T4 (top)/Al 6014-T4 (bottom), and a multi-sensor algorithm applied to the combination of Al 6014-T4 (top)/Al 5052-H32 (bottom). The multi-sensor algorithm with two input variables (CCD and spectrometer) on the same material combination showed the highest accuracy among the models.

Calibration Error in 21-Centimeter Global Spectrum Experiment

The redshifted 21 cm line signal is a powerful probe of the cosmic dawn and the epoch of reionization. The global spectrum can potentially be detected with a single antenna and spectrometer. However, this measurement requires an extremely accurate calibration of the instrument to facilitate the separation of the 21 cm signal from the much brighter foregrounds and possible variations in the instrument response. Understanding how the measurement errors propagate in a realistic instrument system and affect system calibration is the focus of this work. We simulate a 21 cm global spectrum observation based on the noise wave calibration scheme. We focus on how measurement errors in reflection coefficients affect the noise temperature and how typical errors impact the recovery of the 21 cm signal, especially in the frequency domain. Results show that for our example set up, a typical vector network analyzer (VNA) measurement error in the magnitude of the reflection coefficients of the antenna, receiver, and open cable, which are 0.001, 0.001, and 0.002 (linear), respectively, would result in a 200 mK deviation on the detected signal, and a typical measurement error of 0.48°, 0.78°, or 0.15° in the respective phases would cause a 40 mK deviation. The VNA measurement error can greatly affect the result of a 21 cm global spectrum experiment using this calibration technique, and such a feature could be mistaken for or be combined with the 21 cm signal.

Co-Ln (Ln = Ce ∼ Yb) bimetal complexes: Syntheses, structures and their applications as supercapacitor anode materials

In this present, 16 Co-Ln (Ln = Ce ∼ Yb) bimetallic complexes (named as complexes #1-#16 and abbreviated as CoLnPda) were synthesized. Among these complexes, complexes #1-#12 were two-dimensional layered, and complexes #13-#16 were three-dimensional block MOFs. Single crystal x-ray diffractometer (SXRD) and x-ray photoelectron spectrometer (XPS) were applied to confirm the components of the complexes and the oxidation state of the central atom. Optical microscopy, powder x-ray diffractometer (PXRD), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet–visible spectrum (Uv–vis) were used to characterize the complexes. Among these 12 kinds of two-dimensional layered complexes, the obtained pure complexes were evaluated by thermo gravimetric analysis (TG) to illustrate their thermal stability. Next, complex #2 (CoPrPda-n) was selected as an example to illustrate the use of such layered complexes as the precursors to prepare the energy storage materials. Under the atmosphere of nitrogen gas flow, the composite with blade structure (C/Pr2O2CO3/CoO/Co) was formed when the precursor was calcined at 800 °C for 2 h. The sample was used as the electrode material of the supercapacitor and when the current density was 2 A·g−1 in 6 M KOH electrolyte, it showed a specific capacity of 1440 F·g−1. The cycle tests showed that the specific capacitance retained well after 2000 cycles at the current density of 20 A·g−1.

Neutron spectroscopy for Boron Neutron Capture Therapy beams characterization

Boron Neutron Capture Therapy (BNCT) is a therapeutic treatment for malignant tumors that utilizes the nuclear reactions that happen when thermal neutrons are captured by boron-10 atoms to selectively destroy designated cells. Boron-10 atoms are biochemically accumulated inside the tumor target, which is then irradiated with thermal neutrons.In recent years, the possibility to obtain accelerator based intense neutron beams has given a boost to the diffusion of BNCT also in Europe, removing the need of nuclear reactors. In this contest, the monitoring and characterization of the epithermal neutron beams dedicated to BNCT becomes an important issue.The directional neutron spectrometer called NCT-WES (Neutron Capture Therapy Wide Energy Spectrometer) is a single moderator neutron spectrometer composed of a polyethylene cylinder embedding six semiconductor-based detectors positioned at different depths along the cylinder axes. The position of the six detectors is studied in order to maximize the response of each one in a selected neutron energy range. The unfolding of the six simultaneous readings allows to reconstruct the incoming neutron energy spectrum as in a parallelized Bonner Sphere System. A cylindrical collimator situated in the front of the spectrometer makes the instrument sensitive to neutrons coming only from a given direction, which allows to exclude the contribution of the room scattered radiation. The experimental validation of the spectrometer, obtained through several measuring campaigns, is reported and discussed.

Multichannel Doppler fiber-imager spectrometer for spatiotemporal characterization of high-intensity laser-driven plasmas.

We demonstrate a flexible multichannel fiber-based imaging Doppler spectrometer to characterize plasmas in high intensity (≥1 × 1018 W/cm2) laser-plasma experiments at high repetition rates. This instrument collects data from ×21 different plasma locations combining optical fibers and a single imaging spectrometer. This diagnostic maps the plasma velocity evolution as a function of time with sub-pico-second resolution. Experimental results showing 2D velocity measurements of plasma with 20 μm spatial resolution are presented. Intensities of the order of 1018 W/cm2 were used to generate a plasma, while a much less intense, frequency doubled (400nm), probe beam (1011 W/cm2) was used to measure the Doppler shift from the plasma critical surface. The instrument can be scaled to a larger number of channels (e.g., 100) still using a single spectrometer.

Abstract 4440: Topographical investigation of metabolites in excised squares (TIMES2): Comprehensive cross-sectional metabolite quantification of pancreatic cancer in vivo

Abstract Purpose: Pancreatic cancer is a lethal malignancy characterized by complex intratumoral metabolic reprogramming and intercellular nutrient sharing between cells in the tumor microenvironment (TME) that promote pancreatic cancer progression. However, this crosstalk, as well as regional variation in perfusion and oxygenation, can lead to metabolic heterogeneity that has not been appreciated by metabolomics of whole tumors. Here we quantify amino acids and tricarboxylic acid cycle (TCA) intermediates using a novel methodology that allows us to portray global tumor metabolite heterogeneity in a tumor. Methods: Human PaTu-8902 or murine HY19636 (from female KPC mice LSL-KrasG12D; p53 L/+, Ptf1a-Cre+) pancreatic cancer cell lines were orthotopically injected into pancreata of NCr nude mice (n=3) or C57BL/6 mice (n=2). Mice were euthanized after 3-5 weeks and tumors were harvested. Tumor slices were further sectioned into 1mm x 1mm x 1mm cubes using a custom-made multisectional slicing device and each cube location was recorded. Each cube was extracted using methanol, water, and chloroform with labelled amino acid standards, derivitized, and resolved using gas chromatography-mass spectrometry (DB-35MS column with Agilent 7890B gas chromatograph coupled to a single quadrupole 5977B mass spectrometer). 22 metabolites (15 amino acids, 5 TCA intermediates, lactate, and pyruvate) were identified by unique fragments and retention time compared to known standards. Peaks were picked using OpenChrom and analyzed using MATLAB. Data was analyzed using Graphpad Prism. Principal Component Analysis (PCA) was visualized using Python on a Jupyter notebook. Results: Both orthotopic human and murine pancreatic tumors demonstrated striking levels of intratumoral metabolite heterogeneity. Glycine, glutamine, and proline were the amino acids with the highest coefficient of variance, while leucine, isoleucine, and serine had the lowest coefficient of variance. α-ketoglutarate and succinate were the TCA intermediates with highest coefficient of variance. Lactate had the lowest coefficient of variance among all examined metabolites. Spatial mapping of each metabolite demonstrated distinct regions with varying abundance levels of metabolites. PCA demonstrated 75% of variance was carried by PC1 and 10% carried by PC2. Conclusions: This study reveals insights into the degree of intratumoral heterogeneity present in pancreatic tumors that illustrate the difficulty of in vivo metabolomics analysis and suggest that high-resolution (single cell) metabolomics techniques will be critical to study metabolism in the complex TME. Citation Format: Peter Yu, Robert Banh, Albert Sohn, Stephen Martis, Douglas Biancur, Keisuke Yamamoto, Elaine Lin, Alec Kimmelman. Topographical investigation of metabolites in excised squares (TIMES2): Comprehensive cross-sectional metabolite quantification of pancreatic cancer in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4440.

Multi-Channel Hyperspectral Imaging Spectrometer Design for Ultraviolet Detection in the Atmosphere of Venus

The spectroscopic detection of SO2 and unknown UV absorber substance in the H2SO4 cloud layer of Venus’ atmosphere is currently a focal point in the study of the habitability of Venusian atmospheric clouds. This paper addresses the simultaneous detection requirements of multiple substances in the ultraviolet range of Venus’ atmosphere and proposes a multi-channel hyperspectral imaging system design using pupil separation prisms and grating multilevel spectra. The system achieves a multi-channel design by splitting the entrance pupil of the telescope using prisms. Spectra from different channels are diffracted to the same detector through different orders of the grating. The system features a single spectrometer and detector, enabling simultaneous detection of spectra from different channels. It also boasts advantages such as compact size, ultra-high spectral resolution, and simultaneous multi-channel detection. The system design results indicate that within the working spectral range of three channels, the spectral resolution is better than 0.15 nm, surpassing previous in-orbit or current in-orbit planetary atmospheric detection spectrometers. With a Nyquist frequency of 56 lp/mm, the full-field MTF exceeds 0.7. The system’s smile is less than 0.05 μm, and the keystone is less than 0.04 μm, meeting the requirements for imaging quality.

Design method for eliminating spectral line tilt in a multiple sub-pupil ultra-spectral imager (MSPUI).

A multiple sub-pupil ultra-spectral imaging system designed with a single spectrometer and detector can simultaneously detect multiple-channel spectra with ultra-high spectral resolution. However, due to using a prism in the system's front end, the nonlinear dispersion introduces spectral line tilt in the imaging spectra. This phenomenon can lead to bias in the final spectral data. To eliminate this issue, we propose a new design by introducing a second prism to correct this spectral tilt in the system. The angle of spectral line tilt generated by the nonlinear dispersion of the first prism is derived. It provides the theoretical basis for characterizing the second complementary prism. Finally, a UV multiple sub-pupil ultra-spectral imaging system is designed. The system employs two pupil separation prisms and one flat panel array to segment the pupil in three channels, each operating within spectral ranges of 180∼210 nm, 275∼305 nm, and 370∼400 nm, respectively. The spectral resolutions in all three channels are better than 0.1 nm. The corrected spectral line tilt is less than 1/3 of a pixel in the two channels with pupil separation prisms. At a Nyquist frequency of 30 lp/mm, the modulation transfer functions of all three channels are greater than 0.7, ensuring imaging quality. The design results indicate that the method proposed in this paper, utilizing complementary prisms, can effectively correct the spectral line tilt caused by the nonlinear dispersion of the pupil separation prisms. This design approach can be a reference for developing multiple sub-pupil ultra-spectral imaging systems.

Phenolic Profiles and Antitumor Activity against Colorectal Cancer Cells of Seeds from Selected Ribes Taxa

Seeds from several Ribes taxa were surveyed for phenolic compounds and in vitro antiproliferative activity against HT-29 colorectal cancer cells. Total phenolic compounds were analyzed through the Folin–Ciocalteu procedure, while LC coupled to a single mass spectrometer (MS) Orbitrap using an electrospray interface (ESI) was performed to determine the phenolic profiles. Antitumor effects were established using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Total phenolics ranged from 11.4 in R. alpinum to 94.8 mg of caffeic acid equivalents (CAE)/g in R. nigrum ‘Koksa’. Concerning phenolic compounds, four were hydroxylated benzoic acids, four cinnamic acid derivatives, eight flavonoids, and nine flavonoid glycosides. The growth inhibition against HT-29 cancer cells was exercised much better by R. nigrum ‘Koksa’ and Ribes ‘Erkeeni’ (GI50 37 and 42 µg/mL). All Ribes extracts, except for R. nigrum ‘Hara katarlik’, showed higher activity than R. rubrum (GI50 at 72 h: 99 µg/mL). Interestingly, the extract from Ribes ‘Erkeeni’, which exhibited high bioactivity, contains all detected phenolic compounds, unlike R. nigrum ‘Koksa’, which lacks only populnin. Therefore, the high bioactivity found for such extracts could be due to a synergy of all detected compounds. This work constitutes a comprehensive action for expanding knowledge on the phenolic profiles and antitumor activity of GLA-rich Ribes seeds.

Low-cost high-resolution distributed optical fiber system for spectrophotometric analysis of liquid samples: Application to detection of azo dyes

A distributed optical fiber system for spectrophotometric analysis of liquid samples based on light diffusing fiber (LDF) is presented. The sensor is based on a high-density white light emitting diode (LED) strip, which is side coupled to a glass based light-diffusing fiber (LDF) that acts as distributed optical receiver. The light emitted from a single LED propagates through the sample medium, is collected by the LDF and is then detected at the end of the fiber by a mini spectrometer. By sequentially turning on one LED at a time, the system permits the spectrophotometric analysis of the sample medium along the entire fiber length. This approach is capable of a continuous monitoring of absorbance spatial profile of liquid sample in the whole visible spectrum with a single low-cost spectrometer. The experimental results confirm the possibility of distributed measurements with a spatial resolution of about 12 mm over 1 m of measurement range. The approach has been successfully employed to the distributed detection and localization of azo dyes in water with a limit of detection lower than 1 ppm.

Identification and Structural Characterization of Degradation Products of Linagliptin by Mass Spectrometry Techniques.

As part of the development and production of pharmaceuticals, the purity of Active Pharmaceutical Ingredients stands as a fundamental parameter that significantly influences the quality, safety, and efficacy of the final drug product. Impurities in Active Pharmaceutical Ingredients are various unwanted substances that can appear during the whole manufacturing process, from raw materials to the final product. These impurities can stem from multiple sources, including starting materials, intermediates, reagents, solvents, and even degradation products resulting from exposure to environmental factors such as heat, light, or moisture. Their presence can potentially compromise the therapeutic effect of the drug, introduce unexpected side effects, or even pose safety risks to patients. This study aims to conduct the forced degradation of linagliptin and subsequently attempt to identify the resulting degradants. The degradation procedures were carried out in accordance with the guidelines of the International Committee for Harmonization. The degradation profile of linagliptin was investigated under various conditions, including acid hydrolysis, alkaline hydrolysis, oxidation, heat, and light exposure, utilizing ultra-performance liquid chromatography connected to a photo array detector. Identification and characterization of the degradation products were achieved using an ultra-performance liquid chromatography coupled with a single quadrupole detector mass spectrometer and also a liquid chromatography coupled with a high-resolution mass spectrometry. The identified degradation products demonstrate that linagliptin is particularly susceptible to degradation when exposed to acid and peroxide. Whereas, no significant degradation effects were observed under alkali, thermolytic, and photolytic conditions.

Abstract C054: Topographical investigation of metabolites in excised squares (TIMES2): Mapping in vivo of metabolic heterogeneity in pancreatic tumors

Abstract Background: Pancreatic cancer is a lethal malignancy characterized by complex intratumoral metabolic reprogramming and intercellular nutrient sharing between cells in the tumor microenvironment (TME) that promote pancreatic cancer progression. However, this crosstalk, as well as regional variation in perfusion and oxygenation, can lead to metabolic heterogeneity that has not been appreciated by metabolomics of whole tumors. Here we quantify amino acids and tricarboxylic acid cycle (TCA) intermediates using a novel methodology that allows us to portray global tumor metabolite heterogeneity in a tumor. Methods: Human PaTu-8902 or murine HY19636 (from female KPC mice p48-Cre+, KRASLSL-G12D/+, Trp53lox/+) pancreatic cancer cell lines were orthotopically injected into pancreata of NCr nude mice (n=3) or C57BL/6 mice (n=2). Mice were euthanized after 3-5 weeks and tumors were harvested. Tumor slices were further sectioned into 1mm x 1mm x 1mm cubes using a custom-made multisectional slicing device and each cube location was recorded. Each cube was extracted using methanol, water, and chloroform with labelled amino acid standards, derivitized, and resolved using gas chromatography-mass spectrometry (DB-35MS column with Agilent 7890B gas chromatograph coupled to a single quadrupole 5977B mass spectrometer). 22 metabolites (15 amino acids, 5 TCA intermediates, lactate, and pyruvate) were identified by unique fragments and retention time compared to known standards. Peaks were picked using OpenChrom and analyzed using MATLAB. Data was analyzed using Graphpad Prism. Principal Component Analysis (PCA) was visualized using Python on a Jupyter notebook. Results: Both orthotopic human and murine pancreatic tumors demonstrated striking levels of intratumoral metabolite heterogeneity. Glycine, glutamine, and proline were the amino acids with the highest coefficient of variance, while leucine, isoleucine, and serine had the lowest coefficient of variance. α-ketoglutarate and succinate were the TCA intermediates with highest coefficient of variance. Lactate had the lowest coefficient of variance among all examined metabolites. Spatial mapping of each metabolite demonstrated distinct regions with varying abundance levels of metabolites. PCA demonstrated 75% of variance was carried by PC1 and 10% carried by PC2. Conclusions: This study reveals insights into the degree of intratumoral heterogeneity present in pancreatic tumors that illustrate the difficulty of in vivo metabolomics analysis and suggest that high-resolution (single cell) metabolomics techniques will be critical to study metabolism in the complex TME. Citation Format: Peter Yu, Robert Banh, Stephen Martis, Douglas Biancur, Albert Sohn, Elaine Lin, Keisuke Yamamoto, Benjamin Greenbaum, Alec Kimmelman. Topographical investigation of metabolites in excised squares (TIMES2): Mapping in vivo of metabolic heterogeneity in pancreatic tumors [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr C054.

Design and validation of a single cylindrical neutron spectrometer using a gold activation foil

A single cylindrical neutron spectrometer (SCNS) with a gold activation foil was designed for mono-directional high-flux neutron spectrum measurement applications. A total of seven gold activation foils with a diameter of 11 mm and a thickness of 0.2 mm were placed in the moderator as detectors with a depth variation of 15 mm. The moderator was cylindrical with a diameter of 8 cm and a length of 16 cm and made of polyethylene. Outside the moderator is a neutron shield made of 3 mm boron-rubber and 0.5-mm cadmium and covered with an aluminum casing of 5 mm thickness. The response value of each detector was determined by simulation using the Monte Carlo MCNPX 2.7 program. The simulated response detectors was then partially validated by comparing the simulation and the measurement result with an AmBe neutron source, where the difference is around 3%. The obtained results showed that SCNS with a gold activation foil could be used to measure the neutron spectrum in a high-flux neutron field.

Study of a microwave induced plasma as a universal ion source for inorganic and organic mass spectrometry.

A proof-of-concept study of the utilization of a single mass spectrometer for qualitative molecular analysis as well as for quantitative metal determination is described. This was performed with an argon microwave plasma as the ion source coupled to an ion trap mass spectrometer. A microwave induced plasma with tuneable power and gas flow rate was loaded with dried nebulized sample solutions. The commercially available plasma torch was slightly modified to allow the introduction of the sample in different regions of the plasma. Using soft settings, organic compounds introduced in the plasma plume could be detected as protonated molecular ions. Under harsher conditions, elemental analysis was demonstrated for several metals. Lead could be determined with a limit of detection of 150 nM. Minor on-the-fly adjustments of the power, flow rate and sampling distance allowed a mild fragmentation of organic compounds. Ionization differences observed were rationalized by emission spectroscopy, and excitation and rotational temperatures were determined. Simultaneous determination of elemental and molecular information was demonstrated for a rubidium-crown-ether complex. The maximum argon gas consumption for these tasks was below 2 L min-1 and the maximal power used was 90 W.

Development of single moderator-based neutron spectrometer for neutron spectrometry in reactor core

Measuring the neutron spectrum in the reactor core is quite difficult to do. The commonly used technique is using a multi-foil activation-based neutron spectrometer. This technique provides precise positional measurement but low accuracy and is difficult and expensive to manufacture. A technique for measuring the neutron spectrum in the reactor core has been developed using a single moderator-based neutron spectrometer. This technique is simple, easy to make, and inexpensive. The measurement time is relatively fast, and the results are quite accurate. This technique uses a single cylindrical moderator and places seven passive Au detectors with varying depths. The response of each detector is calculated using the Monte Carlo program MCNPX. The neutron spectrum measurement in the reactor core was carried out by placing the spectrometer above the core for a few minutes. The foil activity was measured using a gamma counter, and the neutron spectrum was calculated using the UMG unfolding program. After measuring the neutron spectrum with a single moderator-based neutron spectrometer in the Triga Mark II reactor core, Kartini, compared with the simulation results, the comparison results show values that are close to the same, where the difference is around 2.2%.

Novel burnup measurement system via anti-compton techniques for HTR-10

To enhance the spectrum quality and allow additional data mining for burnup correction in complex reactor operation history and nuclear material accountancy, a novel burnup measurement system based on anti-compton techniques was created, installed, and tested in the HTR-10 system. The novel burnup measurement system suppressed the compton plateau by a factor of greater than 5 in case of end-cap incidence that did increase the pulse-to-compton ratio from 101 to 532 by single channel spectrometer scheme and from about 103 to 577 by dual channel spectrometer scheme for 661.7 keV of radioactive source of Cs-137. When standard calibration and its extension were finished, the new BUMS were operated for several months with HTR-10 since the second half of 2020. Three irradiated fuel pebbles were discharged out for offline measurement including radiochemical analysis for validation. The result presents very good agreement on measured Cs-137 activity with relative error ranging from around −4.3% to −1.4% when comparing corresponding results of online burnup assay by anti-compton BUMS to post irradiated examination by radiochemical analysis. Activities of isotopes were estimated meanwhile to support burnup correction and achieved preliminary satisfying result.

Multipoint Raman Spectrometer Based on a Time-Resolved CMOS SPAD Sensor

The potential of in-line Raman spectrometers for process monitoring applications has been shown for many industrial processes, but in most cases, only one measurement point has been monitored by one spectrometer. In this letter, we describe and demonstrate a novel, time-resolved method for measuring Raman spectra and fluorescence lifetimes from multiple points using a single excitation source and a single spectrometer. This technique is based on a combination of a time-resolved CMOS SPAD (single-photon avalanche diode) line sensor and a fitting optical light guiding system. The line sensor is designed to make multiple individual measurements at intervals of tens of nanoseconds and the optical light guiding system, in turn, produces matching temporal differences for optical signals from different measurement points. Thereby, signals from different points are distinguished in the time domain. A combined Raman and fluorescence lifetime monitoring of two measurement points was demonstrated with an oil-ethanol emulsion sample.

Neutron spectrometry and dosimetry using a multi-shell Single Sphere Neutron Spectrometer with thermo-luminescent and optically stimulated luminescent detectors

A portable neutron spectrometer with concentric multi-shell moderating assembly and TL, OSL detectors has been validated with standard neutron reference fields to generate the neutron spectra and estimate the ambient dose equivalents, H*(10). Further, the system has been used in the mixed neutron–gamma radiation fields at accelerator facility. The neutron fluence and the ambient dose equivalent estimates were verified using the standard reference neutron fields, viz. 241Am-Be, 252Cf, D-T neutron sources. The system was then employed in the accelerator radiation environment to measure the neutron spectral yield from the interactions of 15 and 20 MeV protons with a thick natural Ta target. The results were compared with those obtained from FLUKA simulations. A conventional neutron dose equivalent meter was also used to verify the ambient dose equivalent estimated from the spectrometric measurements. The reproducibility of the neutron spectra and dose values were found to be satisfactory, thereby encouraging the implementation of the portable single sphere neutron spectrometer in complex radiation environment around particle accelerators. Present studies demonstrate the measurements with the in-house built spectrometer for neutron energies up to 20 MeV.