Long-term Radiation Research Articles

Impacts of the STING-IFNAR1-STAT1-IRF1 pathway on the cellular immune reaction induced by fractionated irradiation.

Radiotherapy (RT) combined with immune checkpoint inhibitors has recently produced outstanding results and is expected to be adaptable for various cancers. However, the precise molecular mechanism by which immune reactions are induced by fractionated RT is still controversial. We aimed to investigate the mechanism of the immune response regarding multifractionated, long‐term radiation, which is most often combined with immunotherapy. Two human esophageal cancer cell lines, KYSE‐450 and OE‐21, were irradiated by fractionated irradiation (FIR) daily at a dose of 3 Gy in 5 d/wk for 2 weeks. Western blot analysis and RNA sequencing identified type I interferon (IFN) and the stimulator of IFN genes (STING) pathway as candidates that regulate immune response by FIR. We inhibited STING, IFNAR1, STAT1, and IFN regulatory factor 1 (IRF1) and investigated the effects on the immune response in cancer cells and the invasion of surrounding immune cells. We herein revealed type I IFN‐dependent immune reactions and the positive feedback of STING, IRF1, and phosphorylated STAT1 induced by FIR. Knocking out STING, IFNAR1, STAT1, and IRF1 resulted in a poorer immunological response than that in WT cells. The STING‐KO KYSE‐450 cell line showed significantly less invasion of PBMCs than the WT cell line under FIR. In the analysis of STING‐KO cells and migrated PBMCs, we confirmed the occurrence of STING‐dependent immune activation under FIR. In conclusion, we identified that the STING‐IFNAR1‐STAT1‐IRF1 axis regulates immune reactions in cancer cells triggered by FIR and that the STING pathway also contributes to immune cell invasion of cancer cells.

Improved radiation resistance of an Er-doped silica fiber by a preform pretreatment method.

We report a novel pretreatment method to improve the radiation resistance of Er-doped fiber (EDF). The processing object of this method is EDF preform, and the pretreatment processing involves three steps: deuterium loading, pre-irradiation, and thermal annealing. The effects of pretreatment conditions on the optical loss, gain performance, and radiation resistance of EDF were systematically studied. The relevant mechanisms were revealed using Fourier transform infrared (FTIR), radiation-induced absorption (RIA), and electron paramagnetic resonance (EPR) spectroscopies. The results show that the pretreatment can not only greatly reduce the hydroxyl content of the EDF core, but it can also effectively improve the radiation resistance of EDF. The online test results show that the gain of the commercial, pristine, and pretreated EDFs were reduced by 19.0, 4.2, and 1.3 dB, respectively, corresponding to a decrease of 68.1, 16.2, and 4.7% after 98 krad X-rays irradiation. The high vacuum experiments show that the pretreatment method can maintain long-term stable high radiation resistance. This work provides a reference for the development of high-performance radiation resistant EDFs for use in the lower, middle, and geosynchronous earth orbit.

Degradation of Decabromodiphenyl Ether in an Aerobic Clay Slurry Microcosm Using a Novel Immobilization Technique.

A novel chitosan immobilization technique that entraps photocatalyst and microbes was developed and applied to decompose decabromodiphenyl ether (BDE-209) in a clay slurry microcosm. The optimized conditions for immobilization were obtained by mixing 1.2% (w/v) chitosan dissolved in 1% (v/v) acetic acid with nano-TiO2 particles and the BDE-209-degrading bacterial mixed culture. This aqueous mixture was injected into 1% (w/v) water solution containing sodium tripolyphosphate to form spherical immobilized beads. The surface of the immobilized beads was reinforced by 0.25% (v/v) glutaraldehyde cross-linking. These beads had enough mechanical strength during BDE-209 degradation to maintain their shape in the system at a stirring rate of 200-rpm, while undergoing continuous 365 nm UVA irradiation. This novel TiO2-Yi-Li immobilized chitosan beads system allowed a successful simultaneous integration of photolysis, photocatalysis and biodegradation to remove BDE-209. The remaining percentage of BDE-209 was 41% after 70 days of degradation using this system. The dominant bacteria in the BDE-209-degrading bacterial mixed culture during remediation were Chitinophaga spp., Methyloversatilis spp., Terrimonas spp. and Pseudomonas spp. These bacteria tolerated the long-term UVA irradiation and high-level free radicals present, while utilizing BDE-209 as their primary carbon resource. This new method has great potential for the treatment of a range of pollutants.

Contrast-enhanced ultrasound in pediatric blunt abdominal trauma: a systematic review.

Intra-abdominal injury is a major cause of morbidity in children. Computed tomography (CT) is the reference standard for the evaluation of hemodynamically stable abdominal trauma. CT has an increased risk of long-term radiation induced malignancies and a possible risk associated with the use of iodinated contrast media. Contrast-enhanced ultrasound (CEUS) might represent an alternative to CT in stable children with blunt abdominal trauma (BAT). Nonetheless, CEUS in pediatrics remains limited by the lack of strong evidence. The purpose of this study was to offer a systematic review on the use of CEUS in pediatric abdominal trauma. Electronic search of PubMed, EMBASE and Cochrane databases of studies investigating CEUS for abdominal trauma in children. The risk of bias was assessed using the ROBINS-I tool. This systematic review included 7 studies. CEUS was performed with different ultrasound equipment, always with a curvilinear transducer. Six out of seven studies used a second-generation contrast agent. No immediate adverse reactions were reported. The dose of contrast agent and the scanning technique varied between studies. All CEUS exams were performed by radiologists, in the radiology department or at the bedside. No standard training was reported to become competent in CEUS. The range of sensitivity and specificity of CEUS were 85.7 to 100% and 89 to 100%, respectively. CEUS appears to be safe and accurate to identify abdominal solid organ injuries in children with BAT. Further research is necessary to assess the feasibility of CEUS by non-radiologists, the necessary training, and the benefit-cost ratio of CEUS as a tool to potentially reduce CT scans.

Polythiophene as a near full pH photo-antimicrobial.

Microbial infections are currently one of the world's major public health concerns, the evolution of which has resulted in the development of multiple tolerances (not just drug or antibiotic resistance), including pH (from extremely acidic to alkaline). Currently various types of antimicrobials have been developed. Although effective, they seldom work in the full pH range due to the existence of acid-/base-reaction sites. Here, we found that polythiophene (PT10), a cationic polymer, was capable of both broad-spectrum photo-antimicrobial activity (Gram positive, Gram negative, Fungal, and cyano-bacteria) and broad pH responsiveness (constant 1O2 generation at pH 2-13). The half-maximal inhibitory concentrations (IC50) of PT10 for bacteria living in acidic, neutral, and alkaline media were generally lower than 2 μg mL-1 (except M. aeruginosa, pH 12, ∼30 μg mL-1), which were much lower than common antibiotics and other photosensitizers. Besides, the excellent photostability of PT10 allowed long-term light irradiation for antimicrobial performance. In real-world applications, PT10 was explored for the successful in vivo therapy of oral Candidiasis infection under extreme acidic conditions (pH < 3) and the removal of M. aeruginosa at pH 12. Such near full pH, broad-spectrum photo-antimicrobial activity of polythiophene is appealing for extremely acidic or alkaline applications, such as oral infections, vaginitis, and blooms.

Modelling and the experimental validation of the long-term averaged solar radiation on a tilted solar collector facing the south-east direction

Modelling and the experimental validation of the long-term averaged solar radiation on a tilted solar collector facing the south-east direction

PKULAST-An Extendable Model for Land Surface Temperature Retrieval From Thermal Infrared Remote Sensing Data

Land surface temperature (LST) is one of important parameter in the earth energy and water budget. Recently, open-source modules or packages are emerging as all-in-one solutions to speed up the rapid development and critical application of LST from thermal infrared (TIR) remote sensing data. In this study, we developed a python package, dubbed Peking University LAnd Surface Temperature (PKULAST) model to address the retrieval of LST from TIR remote sensing data with different LST retrieval algorithms, such as Single Channel algorithm, Split Window algorithm, and the Temperature and Emissivity Separation algorithm. Extendable data structures in the model covers common conceptual models used in LST algorithms implementation, such as spectral response functions, surface spectral libraries (ASTER, ECOSTRESS etc.), atmospheric profiles (NCEP, ERA5, MERRA-2, etc.), making it a convenience to construct the processing chain of developing new LST retrieval algorithms and generating LST products. The ASTER imageries are tested to assess the performance of the PKULAST to derive accurate LST. The LST result is then evaluated using long-term ground-based longwave radiation observations collected at seven sites from 2000 to 2021 under cloud-free scenes, and the result shows that the PKULAST model can obtain LST with an uncertainty of 2.7 K in bias, and 4.4 K in RMSE. With the help of predefined extendable data structures and workflows for different sensors, atmospheric profile libraries and surface spectral libraries, new algorithms for retrieving LST can be developed easily. The PKULAST promises to be a tool that seamlessly interoperates with developing LST retrieval algorithms and generating LST scientific products.

REMOTE EFFECTS OF POST-CHORNOBYL IRRADIATION ON THE BIOCHEMICAL CHARACTERISTICS OF MALE SPERMATOZOA

The present research aim was analysis of long-term radiation effects on biochemical characteristics of sperm collected from donors originating from radioactive-polluted territories of Ukraine, namely Zhytomyr oblast, Ivano-Frankivsk oblast, Kyiv oblast and Poltava oblast. Apart from this, the role of radiation component in sperm damaging was assessed. It was found that in the most radiation polluted region - Zhytomyr the sperm samples were characterized by a large proportion of degenerative spermatozoa along with immobile sperms. Early signs of apoptosis development in spermatozoa were shown to progress gradually from Poltava to Zhytomyr. Thus, the apoptotic index for sperm samples was highest in Zhytomyr and lowest in Poltava. Also, raise in accumulated radiation dose was associated with elevation of ROS production in sperm samples. It was shown that the ROS production for Zhytomyr donors was threefold more than for Poltava’s donors and almost twofold more than for donors from Ivano-Frankivsk. Also we found differences in the mitochondrial potential (∆ψ) of spermatozoa too. The total ∆ψ tended to drop down depending on the mean value of radiation accumulated dose, for Kyiv and Zhytomyr the mean values being significantly less than for Poltava. Thus, our investigations have shown that subjects living on radiation polluted territories may generate a great deal of damaged spermatozoa with the hidden molecular and cellular lesions. The latter would predispose inhabitants of radiation polluted regions to male-infertility.

RETINA VESSELS CHANGES IN CHORNOBYL NUCLEAR POWER PLANT EMPLOYEES WHO EXPERIENCED LONG-TERM ABNORMAL RADIATION EXPOSURE AT THE WORKPLACE AS A RESULT OF THE OCCUPATION OF CHORNOBYL NUCLEAR POWER PLANT IN 2022.

to assess the condition of retinal arteries and veins and the level of incorporated 137Cs content in persons who were exposed to prolonged exposure to radiation and non-radiation factors of industrial environment, as they were at the workplace overtime during the occupation of the Chornobyl Nuclear Power Plant in 2022. A comprehensive ophthalmological examination was carried out. Which included the determination of the diameter of the retinal arteries and veins, the arteriovenous ratio, of 55 people from among the personnel of the ChNPP, who worked under the conditions of the occupation of the ChNPP. All those examined were examined on an expert human radiation counter. The results of the ophthalmological examination were compared with the results of earlier examinations of ChNPP employees of the same age groups. It was established that in the examined group, a decrease in the arterio-venous ratio was observed, mainly due to the expansion of retinal veins. Dilatation of the veins was asymmetric, mainly the branches of the central vein of the retina of the right eye were more dilated. Retinal arteries were narrowed in all examined subjects. When comparing the results with the data of previous examinations, it was established that the arterio-venous ratio in this group was probably lower than in previously examined employees of the ChNPP of the same age groups. At the same time, the maximum registered value of the content of incorporated 137Сs was 713 Bq/organism, none of the examined exceeded the control level of 1,000 Bq/organism. Violation of blood circulation in the retina was detected - a probable increase in the arteriovenous ratio due to the expansion of the retinal veins in the personnel of the Chornobyl nuclear power plant who worked under the conditions of the occupation of the ChNPP in 2022. Since the examined subjects did not exceed the control level of incorporated 137Сs content (1,000 Bq/organism), the observed effect may be a consequence of the influence of other, both radiation and non-radiation factors.

Comparison of early forecasts of the incidence of thyroid cancer in residents of the Russian Federation after the Chernobyl accident with observational data

A review of methods for assessing doses in the thyroid gland, predictions of the long-term consequences of its irradiation and the actual incidence of thyroid cancer in residents of four regions of the Russian Federation with the most significant radioactive fallout after the Chernobyl accident are presented. The method for assessing doses in the thyroid gland is based on the results of monitoring in May-June 1986 of radioiodine in the environment, food and in the body of residents. Thyroid doses in the population were used to justify medical and social protection measures, as well as epidemiological studies. In addition, the authorities needed forecasts of the possible morbidity of the population in order to organize adequate medical care. Most of the thyroid cancer cases were predicted among the adult population, which was not confirmed by observations 35 years after the accident. The prognosis of the incidence of thyroid cancer in preschool children differed in different studies due to the use of different coefficients of reducing the biological effectiveness of 131I radiation in the thyroid gland and long-term external and internal irradiation of the whole body with a low dose rate compared to the effect of acute exposure. The increase in the incidence of thyroid cancer among children began five years after the accident at the Chernobyl nuclear power plant. Examples of the dynamics of the incidence for children in the Bryansk region of the Russian Federation are given. The 2018 UNSCEAR Report showed that for 1986-2015, among children and adolescents under 18 years of age on the day of the accident in Belarus, Ukraine and four regions of Russia, more than 19 thousand thyroid cancer cases were detected, of which the share of radiation-induced diseases was estimated at 25%. For four regions of Russia, this amounts to 460 cases with a range of possible estimates from 130 to 900 cases. The highest morbidity was manifested among younger children exposed at the age of 0-4 years. In older children and adolescents, the proportion of radiation-induced diseases has significantly decreased 30 years after the accident. In general, early forecasts of radiation-induced thyroid cancer incidence in children in four regions of the Russian Federation with high levels of radioactive fallout are consistent with the data of subsequent 30-year epidemiological observations within an order of magnitude. With regard to thyroid cancer in adults, such a comparison is difficult, since no radiogenic increase in the incidence has been detected.

Internal Abiotic Components That Influence the Development of Biocorrosion on ETICS Plasters.

Basic factors affecting the appearance of algae discoloration on the surface of the system are recognized effects of the external environment (external temperature and humidity, short- and long-term radiation, precipitation, wind and air pollution). Internal factors are often neglected by international technical documents on the evaluation of the effectiveness of resistance to biocorrosion of the External Thermal Insulation Composite System (ETICS). Based on literature data and in situ research, the basic internal factors responsible for the occurrence or intensification of the biocorrosion process were systematized. Internal factors were divided into two groups: (1) plaster properties and (2) solutions for material layouts and building details. The results of research on these factors indicate that they directly or indirectly influence the humidity condition of plaster and biocorrosion development is a consequence of this state. The opposite issue, the influence of biocorrosion on plaster properties, is analyzed only in patrial way.

Investigation on influencing factors of blood indexes of interventional radiology workers

Objective: To analyze the influencing factors of blood indicators indexes of interventional radiology workers, and provide a theoretical basis for radiological occupational health monitoring, radiation protection monitoring and risk assessment. Methods: In March 2020, a total of 500 interventional radiology workers (interventional group) and 200 non-interventional radiology workers (control group) who underwent an occupational health examination in Liaoning Center for Disease Control and Prevention from 2018 to 2019 were selected as the subjects. The general information, occupation related information, blood routine, fasting blood glucose and thyroid stimulating hormone test results of the subjects were collected. The differences in the levels and abnormal detection rates of blood indexes between the two groups were compared. And the influencing factors of blood indexes of the intervention riodiology workers were analyzed. Results: The lymphocyte count of interventional group[2.10 (1.70, 2.50) ×10(9)/L] was lower than that of control group[2.20 (1.80, 2.60) ×10(9)/L], the difference was statistically significant (P<0.05) . The white blood cell count and lymphocyte count of interventional workers in the service age≤13 years were higher than those of service age≥28 years group, and fasting blood glucose was lower than those of service age ≥28 years group (P<0.05) . The detection rate of abnormal fasting blood glucose of interventional radiology workers in the service age ≤13 years group was lower than that of the service age 14-27 years and service age ≥28 years (P<0.05) . The lymphocyte count and platelet count of interventional radiology workers in annual effective dose<0.5 mSv group was higher than that of annual effective dose≥1 mSv group (P<0.05) . The results of multi-factor linear regression analysis showed that service age, annual effective dose and female gender were the influencing factors of lymphocyte count of interventional radiology workers (b=-0.008, -0.110, -0.167, P<0.05) . Conclusion: Long-term low-dose radiation exposure had certain influence on the lymphocyte count of interventional radiology workers. Service age, annual effective dose and gender are the influencing factors of lymphocyte count in interventional radiology workers. It should be reinforced to the radiological protection monitoring and risk assessment on interventional radiology workers.

Heating Effects in the Structure of Non-metamict Allanite-(La) from Palawan, Philippines

Allanite is one of the most common sources of rare-earth elements (REEs) and contains significant amounts of thorium (Th) and uranium (U). The presence of radioactive Th and U nuclides in the mineral exposes it to long-term radiation. Like other natural minerals containing Th and U, allanite can be used as a natural analog to understand the long-term radiation effects in high-level nuclear waste (HLW) matrices. Allanite group mineral is generally found in the amorphous phase due to structural damage induced by self-irradiation. In this work, crystalline allanite-(La) samples collected in San Vicente, Palawan, Philippines – having a low absorbed -dose of ~ 1014 α-decays/ mg – were heated at 450, 650, and 850 °C to study the response of non-metamict allanite to heating at elevated temperatures, particularly at the early stages of exposure to alpha-particle radiation. An increase in structural order was observed upon heating to 450 and 650 °C, which is exhibited by a decrease in the unit cell volume by 1.6% and a decrease of the full width at half maximum (FWHM) of selected Bragg planes. It was evident that certain Bragg planes respond differently to the annealing temperatures with preferential reorientation. After annealing at 850 °C, however, the loss of OH bonds was observed in the infrared (IR) spectra, and the broadening of Bragg peaks was seen in the x-ray diffraction (XRD) patterns, suggesting an onset of structural degradation. Surface cracks are also seen in the scanning electron microscope (SEM) images. The study shows that the non-metamict allanite-(La) mineral structure responds to heating similarly to that of metamict ones reported in the literature. This study will provide data on the properties of allanite as part of the ongoing studies on radiation damage in silicate matrices.

Autophagy induction regulates aquaporin 3‐mediated skin fibroblast ageing*

Long- and short-term ultraviolet (UV) exposure have distinct biological effects on human fibroblasts. To elucidate the underlying mechanisms of the biological effects of UV exposure on human skin fibroblasts. We subjected human skin fibroblast cells with or without aquaporin 3 (AQP3), death effector domain-containing protein (DEDD) or Beclin1 manipulation to UVA treatment and evaluated autophagy and senescence in them. Short-term UVA irradiation induced autophagy and upregulated AQP3 but not senescence, whereas long-term UVA irradiation inhibited autophagy, AQP3 and trigger senescence in vitro and in vivo. Silencing AQP3 abolished short-term UVA irradiation-induced autophagy and led to cellular senescence, whereas AQP3 overexpression partially rescued the senescence and autophagy inhibition induced by long-term UVA exposure in vitro. Mechanistically, the transcription factor Jun was found to bind to the AQP3 promoter to activate its transcription following short-term UVA exposure. Subsequently, AQP3 interacted with DEDD to induce its ubiquitination-mediated degradation and promote autophagy, and bound to Beclin1 to directly activate autophagy. Finally, autophagy induced by AQP3 overexpression robustly prevented UVA-induced senescence in vitro and in vivo. Our study indicates that AQP3 controls skin fibroblast photoageing by regulating autophagy and represents a potential target for future interventions against skin ageing.

Nonfluorinated, transparent, and antireflective hydrophobic coating with self-cleaning function

Transparent coatings with self-cleaning function have great promise for outdoor applications, such as solar cells, windshields, and lenses. However, their applications are limited by the low transmittance and fluorinated materials. Therefore, it is critical to develop highly transparent and non-fluorinated coatings with low-cost. Herein, we report a transparent, antireflective, and fluorine-free highly-hydrophobic coating. A transmittance of 95.0% was obtained for the coated glass across the broad wavelength range of 394–804 nm, and with a maximum value of 99.5% around 553.5 nm, much better than the bare glass (91.1%). The water contact angle (WCA) of 142.0° and a sliding angle < 10° enable a great self-cleaning function of the coating, which exhibits an impressive thermal stability at − 25–550 ℃, an outstanding resistance to sand ablation and long-term UVA radiation. Therefore, this work may provide not only promising coating but also great inspiration for the development of coating that owns high transmittance and self-cleaning function.

Degradation of silicon detectors under long-term irradiation by 252Cf fission products

The response function of the recoil nuclei in detectors designed for detection of neutrinos or dark matter particles can be determined only through usage of a neutron source with a known energy spectrum. A possible solution for a compact neutron calibration source is a combination of a 252Cf neutron source and a semiconductor detector that detects fission fragments, and thus records the neutron emission moment. This work is devoted to the degradation study of the operating parameters for silicon semiconductor detectors irradiated by fission fragments of the nuclide of 252 Cf. Two types of Si detectors were under investigations - silicon-lithium Si(Li) p-i-n detectors and silicon surface barrier detectors. As a result of the measurements, the maximum permissible radiation doses for the correct operation of both types of detectors and the relation of the received radiation dose to the spectroscopic characteristics of the detectors were determined.

Involvement of Non-Coding RNAs in Chemo- and Radioresistance of Nasopharyngeal Carcinoma.

The crucial treatment for nasopharyngeal carcinoma (NPC) is radiation therapy supplemented by chemotherapy. However, long-term radiation therapy can cause some genetic and proteomic changes to produce radiation resistance, leading to tumour recurrence and poor prognosis. Therefore, the search for new markers that can overcome the resistance of tumor cells to drugs and radiotherapy and improve the sensitivity of tumor cells to drugs and radiotherapy is one of the most important goals of pharmacogenomics and cancer research, which is important for predicting treatment response and prognosis. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), may play important roles in regulating chemo- and radiation resistance in nasopharyngeal carcinoma by controlling the cell cycle, proliferation, apoptosis, and DNA damage repair, as well as other signalling pathways. Recent research has suggested that selective modulation of ncRNA activity can improve the response to chemotherapy and radiotherapy, providing an innovative antitumour approach based on ncRNA-related gene therapy. Therefore, ncRNAs can serve as biomarkers for tumour prediction and prognosis, play a role in overcoming drug resistance and radiation resistance in NPC, and can also serve as targets for developing new therapeutic strategies. In this review, we discuss the involvement of ncRNAs in chemotherapy and radiation resistance in NPC. The effects of these molecules on predicting therapeutic cancer are highlighted.

Stability of Borna disease virus-based episomal vector under physical and chemical stimulation.

Borna disease virus (BoDV), a nonsegmented, negative-sense RNA virus, establishes persistent infection and replicates in the cell nucleus. Since BoDV genomic RNA exists as episomal RNA, the host genome is not invaded by BoDV infection. These unique features make BoDV a promising gene delivery system as an RNA virus-based episomal vector (REVec). Previously, the stable expression of genes of interest in vitro and in vivo using a REVec was reported. For the clinical application of a REVec, the fundamental properties under various physical and chemical conditions must be determined to develop purification processes, supply chains, and biosafety management. This study investigated the effects of the following conditions on the inducibility of transmission-defective ΔG-REVec: freeze-thaw cycles, dehydration, UV, temperature, pH, and reagents for virucides and laboratory experiments. Although the titer of ΔG-REVec was not influenced by the freeze-thaw process or 5 minute incubation at ≤50°C, ΔG-REVec was significantly inactivated by incubation at ≥70°C for 5 minutes. The induction titer of ΔG-REVec was decreased by long-term incubation, dehydration, and UV irradiation in a temperature- and time-dependent manner. ΔG-REVec was sensitive to lower pH and inactivated by chemical reagents under general conditions. These results provide important knowledge for developing the clinical use of REVec and biosafety management.

Technological exploitation of the JET neutron environment: progress in ITER materials irradiation and nuclear analysis

Several experimental activities have been conducted within the ‘ACT’ sub-project under the EUROfusion WPJET3 programme with the purpose to ultimately irradiate ITER materials within the JET D–T neutron environment. The latest results of these activities are presented in this work. The ITER materials include: poloidal field coil jacket samples and toroidal field coil radial closure plate steels, EUROFER 97-2 steel, W and CuCrZr materials from the divertor, Inconel 718, CuCrZr and 316L stainless steel for blanket modules and vacuum vessel forging samples. The experimental results presented here include gamma spectrometry measurements and analysis obtained from post-irradiated samples following the 2019 C38 (D–D) campaign, where a total of 97 samples were irradiated in a newly prepared long-term irradiation station assembly, comprising 27 ITER material samples, 70 dosimetry foils and two combination-foil detectors, known as ‘VERDI’ detectors. Measurements using a range of dosimetry reactions that are present in the IRDFF-II nuclear data file have also been used in preparatory work to characterise the irradiation locations. The latest ITER sample measurement results are presented along with initial comparisons with corresponding neutron transport and activation calculation predictions.

PWO based electromagnetic calorimetry to operate at a low temperature

The degradation of the optical transmittance under ionising radiation of the scintillation crystal in the scintillation spectral range leads to the losses of the light output, which results in the deterioration of the energy resolution and limits the operation time of the calorimeter made of the scintillator. This effect is especially prominent for calorimeters operating at a low temperature. The use of a lead tungstate scintillation crystal PbWO4 in calorimetry at a low temperature in the range from –20 to –45 °C provides a threefold increase in its scintillation yield, which causes a significant improvement in the energy resolution in the range up to 10 MeV. Keep on this feature is critically important for hadron spectroscopy. However, as the temperature of the PbWO4 crystal is lowered, the rate of spontaneous relaxation of colour centers created under ionising radiation significantly slows down, which shifts the dynamic level of the induced absorption towards a higher value under long-term irradiation of high-energy physics experiments. A comparison is made of the spontaneous relaxation of induced absorption in the spectral region of scintillations with stimulated relaxation upon irradiation of samples by infrared photons of different wavelengths. It is shown that the relaxation of colour centers can be accelerated up to one thousand times. Thus, recovery stimulation allows fast and efficient in situ recovery of the crystal optical transmittance either at beam-off periods or online at data acquisition. The application can substantially improve or extend the running period of the PWO based calorimeters at low temperatures by keeping the radiation damage at a tolerable level.