In-beam gamma rays of CSNS Back-n characterized by black resonance filter

The back-streaming white-neutron beamline(Back-n)of the China Spallation Neutron Source is an essential neutronresearch platform built for the study of nuclear data,neutron physics,and neutron applications.Many types of cross-sectional neutron-reaction measurements have been performed at Back-n since early 2018.These measurements have shown that a significant number of gamma rays can be transmitted to the experimental stations of Back-n along with the neutron beam.These gamma rays,commonly referred to as in-beam gamma rays,can induce a non-negligible experimental background in neutron-reaction measurements.Studying the characteristics of in-beam gamma rays is important for understanding the experimental background.However,measuring in-beam gamma rays is challenging because most gamma-ray detectors are sensitive to neutrons;thus,discriminating between neutron-induced signals and those from in-beam gamma rays is difficult.In this study,we propose the use of the black resonance filter method and a CeBr_(3) scintillation detector to measure the characteristics of the in-beam gamma rays of Back-n.Four types of black resonance filters,^(181)Ta,^(59)Co,^(nat)Ag,and^(nat)Cd,were used in this measurement.The time-of-flight(TOF)technique was used to select the detector signals remaining in the absorption region of the TOF spectra,which were mainly induced by in-beam gamma rays.The energy distribution and flux of the in-beam gamma rays of Back-n were determined by analyzing the deposited energy spectra of the CeBr_(3) scintillation detector and using Monte Carlo simulations.Based on the results of this study,the background contributions from in-beam gamma rays in neutron-reaction measurements at Back-n can be reasonably evaluated,which is beneficial for enhancing both the experimental methodology and data analysis.

Gamma Ray Radiation Effect on Bi2WO6 Photocatalyst

The development of Bi2WO6-based materials has become one of research hotspots due to the increasing demands on high-efficient photocatalyst responding to visible light.In this work,the effect of high energy radiation(γ-ray)on the structure and the photocatalytic activity of Bi2WO6 nanocrystals was first studied.No morphological change of Bi2WO6 nanocrystals was observed by SEM underγ-ray radiation.However,the XRD spectra of the irradiated Bi2WO6 nanocrystals showed the characteristic 2θof(113)plane shifts slightly from 28.37o to 28.45o with the increase of the absorbed dose,confirming the change in the crystal structure of Bi2WO6.The XPS results proved the crystal structure change was originated from the generation of oxygen vacancy defects under high-dose radiation.The photocatalytic activity of Bi2WO6 on the decomposition of methylene blue(MB)in water under visible light increases gradually with the increase of absorbed dose.Moreover,the improved photocatalytic performance of the irradiated Bi2WO6 nanocrystals remained after three cycles of photocatalysis,indicating a good stability of the created oxygen vacancy defects.This work gives a new simple way to improve photocatalytic performance of Bi2WO6 through creating oxygen vacancy defects in the crystal structure by-ray radiation.

An investigation of gamma ray mass attenuation from 80.1 to 834.86 keV for fabric coating pastes used in textile sector

In the present study,we investigate several textile coating pastes used in the market based on their radiation protection capability for gamma rays.The gamma ray mass absorption coefficients of some coating pastes doped with antimony,boron and silver elements have been investigated.It has been determined that the gamma ray mass attenuation coefficient decreases rapidly as the energy of the gamma rays increases.It was determined that the doping of the main printing paste with silver and antimony considerably increased the gamma ray absorption capability of main paste.However,the doping of the paste with boron reduces the mass absorption of gamma rays.In particular,the gamma ray mass absorption power of the main paste doped with silver and antimony was determined to be useful in the gamma energy range from 80 to 140keV.This indicates that the newly doped textile material may be considered for radiation protection in the case of low-energy gamma rays.

Effect of ^(137)Cs Gamma Rays to Panicles on Rice Anther Culture

Panicles of an indica rice line TM7-5 were subjected to radiation with 137^Cs gamma rays at 0 （control）, 5, 10, 15 and 20 Gy respectively, and then its anthers were cultured. There were slight differences among the treatments in peak emerging time of callus initiation, from 38 to 44 days after inoculation （DAI） as well as the frequency of callus initiation （2.3-3.5%）. About two thirds calli were induced before 44 DAI, and calli derived beyond 60 DAI lost the regeneration ability. Green plant regeneration frequency was significantly stimulated from two- to three-fold by irradiation of the 1370S gamma rays compared with the control, and the maximum was 22,81% （15 Gy）. The culture ability based on callus initiation and green plantlet regeneration was 0.19% for the control while it was over 0.45% for all the irradiated treatments, and the maximum was 0,59% for 15 Gy treatment. The advantages of panicle irradiation before anther culture and the potential application in rice anther culture, especially for recalcitrant indica rice, were discussed.

Troubleshooting Distillation Column by Gamma Ray Scanning Technique

A digitally controlled three-dimensional gamma-scanning apparatuswas developed and used to trou- bleshoot distillation column is thepresent investigation. In a 140 mm (ID) model column, variousmalfunctional phenomena, both rate and process related conditions andstructural problems, which may be frequently encountered in theoperation of tray and packing columns, were experimentally simulatedand tested with the developed scan- ning system. The experimentalresults showed that the scanning spectra can fairly reflect thesimulated phenomena.

Tests on Application of Soil Magnetic and Integrated Gamma Ray TLD and TC Methods to the Exploration of Sandstone-Type Uranium Deposits

This paper introduces the test results of the soil magnetic survey and the integrated gamma-ray TLD and TC methods for sandstone-type uranium exploration and describes the prospecting mechanism. The tests have proved that these approaches have yielded good results on classifying the sedimentary facies, defining the redox transitional zones and reflecting deep mineralization information. They may probably become new methods on searching for sandstone-type uranium deposits.

Modelling and Analysis of the Hubble Diagram of 280 Type SNIa Supernovae and Gamma Ray Bursts Redshifts with Analytical and Empirical Redshift/Magnitude Functions

Based on an analysis of 280 Type SNIa supernovae and gamma-ray bursts redshifts in the range of z = 0.0104 - 8.1 the Hubble diagram is shown to follow a strictly exponential slope predicting an exponentially expanding or static universe. At redshifts > 2 - 3 ΛCDM models show a poor agreement with the observed data. Based on the results presented in this paper, the Hubble diagram test does not necessarily support the idea of expansion according to the big-bang concordance model.

Layered Ag-graphene films synthesized by Gamma ray irradiation for stable lithium metal ano des in carb on ate-based electrolytes

Lithium metal batteries are considered as high energy density battery systems with very promising prospects and have bee n widely studied.However,The uncon trollable plating/strippi ng behavior,infinite volume change and den drites formation of lithium metal anode restrict the applicati on.The unc on trolled n ucleati on of lithium caused by the non uniform multi-physical field distributions,can lead to the undesirable lithium deposition.Herein,a graphene composite uniformly loaded with Ag nano-particles(Ag NPs)is prepared through a facile Gamma ray irradiation method and assembled into self-supported film with layered structure(Ag-rGO film).Whe n such film is used as a lithium metal an ode host,the uncontrolled deposition is converted into a highly nucleation-induced process.On one hand,the Ag NPs distributed between the in terlayers of graphe ne can preferentially induce lithium nu cleati on and en able uniform deposition morphology of lithium between interlayers.On the other hand,the stable layered graphene structure can accommodate volume change,stabilize the interface between anode and electrolyte and inhibit dendrites formation.Therefore,the layered Ag-rGO film as anode host can reach a high Coulombic efficiency over 93.3% for 200 cycle(786 h)at a current density of 1 mA cm^(-2) for 2 mAh cm^(-2) in carbonate-based electrolyte.This work proposes a facile Gamma ray irradiation method to prepare metal/3D-skeleton structure as lithium anode host and demonstrates the potential to regulate the lithium metal deposition behaviors via manipulating the distribution of lithiophilic metal(e.g.Ag)in 3D frameworks.This may offer a practicable thinking for the subsequent design of the lithium metal anode.

Collimated gamma rays from laser wakefield accelerated electrons

Betatron radiation from laser wakefield accelerated electrons and X-rays scattered off a counter-propagating relativistic electron bunch arecollimated and hold the potential to extend the energy range to hard X-ray or gamma ray band. The peak brightness of these incoherent radiations could reach the level of the brightest synchrotron light sources in the world due to their femtosecond pulse duration and source sizedown to a few micrometers. In this article, the principle and properties of these radiation sources are briefly reviewed and compared. Then wepresent our recent progress in betatron radiation enhancement in the perspective of both photon energy and photon number. The enhancement istriggered by using a clustering gas target, arousing a second injection of a fiercely oscillating electron bunch with large charge or stimulating aresonantly enhanced oscillation of the ionization injected electrons. By adopting these methods, bright photon source with energy over 100 keVis generated which would greatly impact applications such as nuclear physics, diagnostic radiology, laboratory astrophysics and high-energydensity science.

A Petrophysical Approach to Evaluation from Measured While Drilling Gamma Ray, Case Study in the Powder River and Delaware Basins

One of the most common subsurface data sets that is easily accessible and often underutilized is the acquired measuring while drilling (MWD) gamma ray (GR-GAPI) log. Data is acquired from a given gamma ray tool positioned within the drill string and pulsed up to the surface through the mud column in the wellbore. Typical use of the data is for subsurface geologists, drillers and others to correlate the data to known stratigraphic signatures and steer wells through horizontal target zones. Through that correlation, an association to the geologic stratigraphic column can be made and the team of subsurface scientists adjusts where, how fast, and why they choose to continue drilling. The technique of correlation applies to both the conventional and unconventional application. In the unconventional application, the data is also typically acquired along the length of the horizontal wellbore. From a petrophysical standpoint, just acquiring a gamma ray can limit the amount of information and ability to fully evaluate the properties along the length of the well. In this study, we share and demonstrate how to utilize the MWD GR for petrophysical evaluation beyond just a volume of shale or volume of clay interpretation. The workflow will allow full integration of a comprehensive petrophysical evaluation that can then be utilized to support all subsurface understandings and modelling efforts.

Study the Attenuation Coefficient of Granite to Use It as Shields against Gamma Ray

The present work investigates the linear and mass attenuation coefficients for gamma rays practically and theoretically by using spectroscopy gamma ray (UCS-20) and program (XCOM)) for various types of common use granite, and compares them with the lead because of its high blocking ability for this type of radiation. This paper concluded through linear and mass attenuation coefficients measurements that these coefficients decrease with increasing incident photons energy. Measurements also showed that the linear attenuation coefficients appropriate linearly with density while mass attenuation coefficients do not get affected.

Design of Tubular Azimuth Gamma Ray Logging Tool

On the Gamma ray reception study, this paper presents the heavy metal shielding method, which is using C type heavy metal to shield Sodium iodide scintillation crystal. By rotating the drilling tools to scan and detect the gamma ray which are around the borehole wall formation, On study of angle measurement study, base on accelerometers and fluxgate sensors to design the algorithm which can confirm the detecting instrument measurement window position;Moreover, the paper also presents the Rock formation identification method, which is using changing tendency and sequencing of high side and low side gamma to decide the position of the drilling tool. Field experiments showed that the tool can effectively identify the reservoir and rock formation.

Preparation and Properties of Glass with High Transmittance and Intense Gamma Ray Shielding

Introduction As a kind of high-energy electromagnetic radiation,gamma rays can lead to radiation effect and environmental pollution.To ensure the reliability and safety utilization of gamma radiations in different areas,materials with reliable gamma shielding performances should be developed.The existing efforts are to use glasses as alternative for the conventional radiation shielding materials.As a typical window material,glass itself has attracted wide attention due to its unique chemical and physical advantages.Among them,lead-based radiation shielding materials are widely used in the field of ionizing radiation protection due to their reliable physical properties.In the nuclear industry and high energy physics laboratories,different materials can be used for temporary or permanent shielding.The lead-based glass doped with heavy metal oxide PbO is widely used in the field of radiation shielding for a long time with reliable light transmission properties,which facilitates the observation and monitoring of radiation areas.In this paper,three kinds of transparent silicate glass with different PbO contents were prepared by a high-temperature melting forming method.The gamma-rays protection abilities of the three kinds of glass were investigated through experimental and thermotical methods.The chemical and thermal stability of the glass were also analyzed.In addition,the influence mechanism of the structure and performance differences of the three kinds of glass was also discussed.Methods Analytical pure quartz sand(SiO_(2),purity 99.5%,in mass,the same below),lead monoxide(PbO,purity 99.0%),potassium nitrate(KNO3,purity 99.0%)and sodium nitrate(NaNO3,purity 99.0%)were selected as raw materials for preparation of three kinds of gamma-rays shielding glass materials by a high-temperature melting method.An appropriate amount of raw materials was thoroughly mixed and added to 3 L quartz crucible and heated in air at 1200℃.Then the raw materials were melted at 1250℃for 14 h.The uniform melt was quickly poured into the 150 mm×150 mm×50 mm stainless steel mold preheated at 750℃.Finally,the quenched glasses were annealed at 450℃for 12 h and cooled naturally to room temperature.The density of the three glass samples was tested based on the Archimedes principle.The thermal expansion coefficient of glass samples was measured by a model Netzsch DIL 402 expansion coefficient tester.The infrared spectra were measured by a model Perkinelmer Spectrum 100 FTIR Spectrometer.The Raman spectra were tested by a model HORIBA LabRAM HR800 high-resolution Raman spectrometer.The gamma ray shielding test was completed in China Academy of Engineering Physics.The chemical stability test was completed in Chengdu Guangming Glass Co.,LTD.The acid stability and moisture stability of the glass samples were tested according to the national standards GB/T 7962.14-2010 and GB/T 7962.15-2010,respectively.The thermal stability of the galss was also determined.Results and discussion Glass structure becomes more compact with the exchange of Pb alternatives of Si,K and Na.Increasing the density of glass is conducive to improving its shielding performance,but this leads to significant changes in the optical properties,thermal properties and chemical stability of glass due to the increase of heavy metal content.The preparation of high transmittance glass is more difficult.The coefficient of thermal expansion of glass samples gradually decreases from 103.6×10^(-7)℃-1 to 89.2×10^(-7)℃-1,and the values of Tg and Tf also decrease with the increase of mass fraction of PbO in glass components.The change of the thermal properties of the three glass samples is a result of the joint action of PbO,Na2O and K2O.The FTIR spectra show that the added PbO is transformed into[PbO4]units with 4 coordination numbers into the network under the condition of sufficient free oxygen as PbO content in the glass increases.These[PbO4]units participate in the formation of silicate networks.The Raman spectra indicate that the silicate network structure is de-polymerized as PbO content is increased,and the enhancement of the characteristic vibrational peaks corresponding to the Pb-Si-O indicates an increase in the degree of participation of the[PbO4]units in the formation of silicate network. The ion packing density of the glass sample gradually increases with the increase of PbO content,which shows that the compressible free volume per unit volume of the glass sample becomes smaller. PbO with a high concentration(x = 0.50 and x = 0.66) is used as a glass-forming agent, and the [PbO4] structural units can form a connection structure with thesilicon oxide tetrahedron, which plays a role in repairing the glass network.The permeability of the glass can be improved via strictly controlling the iron content of the introduced raw materials andmaking full use of the double alkali effect of the glass. The actual shielding performance of glass is not a result of simple addition ofvarious components. This can be affected by the actual composition content of the glass, melting process and endoplasmic uniformity.The influence of glass expansion coefficient on the thermal stability is much greater than that on its chemical stability.Conclusions PbO with a high concentration (x = 0.50 and x = 0.66) was used as a glass-forming agent, and the [PbO4] structuralunits could form a connection structure with the silicon oxide tetrahedron, playing a role in repairing the glass network. The measuredshielding rate of 60Co gamma-ray could be 50% and the glass with 50% PbO content (in mass fraction) exhibited a lineartransmission rate of more than 85% in the range of 400-800 nm. In addition, the reliable thermal and chemical stabilities were alsoreflected in the glass.

Genetic Enhancement of Indigenous Cowpea with Gamma-Ray Induced Trait Variation

Production of cowpea (Vigna unguiculata (L.) Walp.), a staple legume crop in Sub-Saharan Africa, faces challenges due to biotic and abiotic constraints. Induced mutagenesis was deployed to create genetic variation in two cowpea varieties (KVX396-4-5-2D and Moussa local). The radio-sensitivity tests led to determe the lethal dose 50 (LD50) corresponding to 230 Gy and 220 Gy for KVX396-4-5-2D and Moussa local varieties, respectively. Dried seeds (M0) of each variety were gamma-ray irradiated with LD50 − 50, LD50 and LD50 + 50. M1 seeds were advanced to generate M2, M3 and M4 mutants using the single-seed-descent method. M4 mutant lines were evaluated in rain-fed conditions using a randomized complete block design to assess phenotypic differences. Data on seven qualitative and eleven quantitative traits were collected. The results indicated that the mutation induced variability in three qualitative traits: in KVX 396-4-5-2D mutant lines, with flower and seed color frequencies at 2.61% and 0.56% respectively, and pod dehiscence at a frequency of 0.24%. While in Moussa local mutants, a pod color changed at a frequency of 17%. ANOVA results revealed significant differences between mutants of both varieties for all quantitative traits, including photosynthetic parameters. Positive correlations were observed between leaf diameter and 100-seed weight, and between branch number and 100-seed weight. Hierarchical clustering revealed three clusters among KVX 396-4-5-2D mutants and six clusters among Moussa local mutants. Early maturity and high foliage were induced traits in Cluster 3 of KVX 396-4-5-2D mutants while high hundred-seed weight was induced in Cluster 6 of Moussa local mutants.

Simulation of a soft-gamma-ray polarimeter on board a microsatellite

Gamma-ray polarimetry is a new and prospective tool for studying extremely high-energy celestial objects and is of great significance for the field of astrophysics.With the rapid development of microsatellite technology,the advantages of space exploration have become increasingly apparent.Therefore,we simulated a soft-gamma-ray polarimeter for a microsatellite based on the Compton scattering principle.We performed detailed Monte Carlo simulations using monoenergetic gamma-ray linear-polarization sources and Crab-like sources in the energy range of 0.1-10 MeV considering the orbital background.The polarimeter exhibited excellent polarization detection performance.The modulation factor was 0.80±0.01,and the polarization angles were accurate within an error of 0.2°at 200 keV for on-axis incidence.For the Crab-like sources for on-axis incidence,the polarization degrees were consistent with the set values within the error tolerance,the modulation factor was 0.76±0.01,and the minimum detectable polarization reached 2.4%at 3σfor an observation time of10^(6) s.Additionally,the polarimeter exhibited recoil electron tracking,imaging,and powerful background suppression in a large field of view(FoV;∼2πsr).The proposed polarimeter meets the requirements of a space soft-gamma-ray polarization detector and has promising research prospects.

EJUSTCO:Monte Carlo radiation transport code hybrid with ANN model for gamma-ray shielding simulation

Gamma ray shielding is essential to ensure the safety of personnel and equipment in facilities and environments where radiation exists.The Monte Carlo technique is vital for analyzing the gamma-ray shielding capabilities of materials.In this study,a simple Monte Carlo code,EJUSTCO,is developed to cd simulate gamma radiation transport in shielding materials for academic purposes.The code considers the photoelectric effect,Compton(incoherent)scattering,pair production,and photon annihilation as the dominant interaction mechanisms in the gamma radiation shielding problem.Variance reduction techniques,such as the Russian roulette,survival weighting,and exponential transformation,are incorporated into the code to improve computational efficiency.Predicting the exponential transformation parameter typically requires trial and error as well as expertise.Herein,a deep learning neural network is proposed as a viable method for predicting this parameter for the first time.The model achieves an MSE of 0.00076752 and an R-value of 0.99998.The exposure buildup factors and radiation dose rates due to the passage of gamma radiation with different source energies and varying thicknesses of lead,water,iron,concrete,and aluminum in single-,double-,and triple-layer material systems are validated by comparing the results with those of MCNP,ESG,ANS-6.4.3,MCBLD,MONTEREY MARK(M),PENELOPE,and experiments.Average errors of 5.6%,2.75%,and 10%are achieved for the exposure buildup factor in single-,double-,and triple-layer materials,respectively.A significant parameter that is not considered in similar studies is the gamma ray albedo.In the EJUSTCO code,the total number and energy albedos have been computed.The results are compared with those of MCNP,FOTELP,and PENELOPE.In general,the EJUSTCO-developed code can be employed to assess the performance of radiation shielding materials because the validation results are consistent with theoretical,experimental,and literary results.

The 111-Years-Old Cosmic Ray Puzzle Has Been Solved?

We show that recently multi-messenger astronomy has provided compelling evidence that the bulk of high energy cosmic rays (CRs) are produced by highly relativistic narrow jets of plasmoids launched in core collapse of stripped-envelope massive stars to neutron stars and stellar mass black holes. Such events produce also a visible GRB if the jet happens to point in our direction. This has been long advocated by the cannon ball (CB) model of high energy CRs and GRBs, but the evidence has been provided only recently by what were widely believed to be unrelated discoveries. They include the very recent discovery of a knee around TeV in the energy spectrum of high energy CR electrons, the peak photon energy in the “brightest of all time” GRB221009A, and the failure of IceCube to detect high energy neutrinos from GRBs, including GRB221009A. They were all predicted by the cannonball (CB) model of high energy CRs and GRBs long before they were discovered in observations, despite a negligible probability to occur by chance.

Sequences in the Hardness Ratio-Peak Energy Plane of Gamma-Ray Bursts

The narrowness of the distribution of the peak energy of the νFν spectrum of gamma-ray bursts (GRBs) and the unification of GRB populations are great puzzles yet to be solved. We investigate the two puzzles based on the global spectral behaviors of different GRB populations, the long GRBs, the short GRBs, and the X-ray flashes (XRFs), in the HR?Ep plane (HR the spectral hardness ratio) with BATSE and HETE-2 observations. It is found that the long GRBs and the XRFs observed by HETE-2 seem to follow the same sequence in the HR?Ep plane, with the XRFs at the low end of this sequence. We fit the sequence by a universal Band function, and find that this sequence is mainly defined by the low energy index α, and is insensitive to the high energy index, β. With fixed β = ?5, a best fit is given by α = ?1.00 with χ2min/dof = 2.2. The long and short GRBs observed by BATSE follow significantly different sequences in the HR?Ep plane, with most of the short GRBs having a larger hardness ratio than the long GRBs at a given Ep. For the long GRBs a best-fit yields α = ?0.30 and β = ?2.05. For the short GRBs, a best fit gives α = ?0.60 with χ2min = 1.1 (with β fixed at -2.0 because it is numerically unstable). The α value for the short GRBs is significantly greater than that for the long GRBs. These results indicate that the global spectral behaviors of the long GRB sample and the XRF sample are similar, while that of the short GRBs is different. The short GRBs seem to be a unique subclass of GRBs, and they are not the higher energy extension of the long GRBs.

Statistical studies of optically dark gamma-ray bursts in the Swift era

We compare the properties of optically dark GRBs, defined by the optical-to-X- ray spectral indexβox 〈 0.5, and normal ones discovered by the Swift satellite before the year 2008 in a statistical way, using data collected from the literature and online databases. Our sample includes 200 long bursts, 19 short bursts, and 10 with measured high redshifts （z ≥ 4）. The ratio of dark bursts is found to be -10% - 20%, and is similar among long bursts, short ones, and the high-z sub-sample. The result for long bursts is consistent with both the pre-Swift sample and studies by other authors on smaller Swift samples. The existence of dark short GRBs is pointed out for the first time. The X-ray derived hydrogen column densities of dark GRBs clearly prefer large values compared with those of normal bursts. This supports the dust extinction scenario as the main cause of dark GRBs. Other possibilities like very high redshifts and non-standard emission mechanisms are less likely, although not fully excluded.

The Role of T_(50) in the Classification of Gamma-ray Bursts

The role of T50 in classifying gamma-ray bursts (GRBs) is investigated. We take T50 = 0.7 s as the line of division and find that some bursts belonging to the class of long bursts defined by T90 ≥ 2 s now become short bursts (sample 1), while some belonging to the class of short bursts defined by T90 < 2 s now become long bursts (sample 2). We study how these sources are affected by the two methods of classification and find the change of classes of sample 1 is due to some peculiar properties of the light curves. Based on their characters, most of the bursts of sample 1 should be taken as short bursts.