Cross section determination of^(27)Al(n,2n)^(26)Al reaction induced by 14-MeV neutrons uniting with D-T neutron activation and AMS techniques

Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion reactors.At the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He reaction.The^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of Sciences.The neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb reaction.The measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature data.The newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental values.The obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.

针刺调节小胶质细胞活化治疗阿尔茨海默病:神经炎症机制研究进展

Microglia(MG)activation and its mediated neuroinflammation are closely related to the occurrence and deterioration of Alzheimer's disease(AD).Acupuncture is one of the effective approach for AD,which can relieve the symptoms and slow the deterioration of AD.Based on the role of MG activation and its induced pro-inflammatory and anti-inflammatory phenotypes in neuroinflammation,this paper reviews the related literature on the mechanism of acupuncture in regulating MG activation and relieving neuroinflammation in AD.It is found that acupuncture can inhibit abnormal MG activation by regulating the release of MG surface immune receptors and pro-inflammatory/anti-inflammatory cytokines.It can also modulate the activity of signaling pathways associated with MG polarization,downregulate the expression of Ml,and promote MG polarization towards the M2 phenotype.Additionally,it adjusts the imbalance between M1 and M2 phenotypes of MG,thereby relieving the neuroinflammatory pathological procession of and repairing the neuronal damage so as to achieve its therapeutic effect.

Consistency test of PMT SPE spectrum from dark-noise pulses and LED low-intensity light

Photomultiplier tube(PMT)has been an essential instrument for low background experiments,and the accuracy of single photoelectron(SPE)calibration will directly affect the energy reconstruction of the detector.The SPE spectrum can be acquired from the charge distribution of dark-noise pulses or the low-intensity light signal triggered by LED.However,there are arguments on whether the two methods are consistent.In this paper,the Hamamatsu R5912-20mod PMT and the EMID642KNFL PMT have been tested adopting the two methods with signal waveform recording electronics.As comparison,traditional charge-to-digital conversion system is also used to test SPE spectrum.The results show that they are consistent when the PMTs are working at typical recommended high voltage(HV).

Calibration of liquid argon detector with ^(83m)Kr and ^(22)Na in different drift fields

Introduction Liquid noble gases are widely used as targets in low background search experiments,particularly in direct dark matter search experiments.83mKr is an excellent low-energy internal calibration source for future larger liquid noble gas detectors.Purpose To calibrate liquid argon detector with 83mKr in different drift fields and to study the correlation between light yield and drift fields.Method A dual-phase LAr prototype detector was designed to study the 83mKr responses in liquid argon.83mKr atoms are produced through the decay of 83Rb and introduced into the LAr detector through the circulating purification system.Conclusion We report that the light yield reaches 7.26±0.02 pe/keV for 41.5 keV from 83mKr and 7.66±0.01 pe/keV for 511 keV from 22Na,as a comparison.After stopping the fill,the rate decays of 83mKr are with a fitted half-life of 1.83±0.11 h,which is consistent with the reported value of 1.83±0.02 h.The light yield that varies with the drift electric field from 0 to 200 V/cm has also been reported.

Prospects of detecting the reactor v_(e)-Ar coherent elastic scattering with a low-threshold dual-phase argon time projection chamber at Taishan

Background We propose to measure the coherent elastic neutrino-nucleus scattering(CEvNS)using a dual-phase liquid argon time projection chamber(TPC)with 200 kg fiducial mass.The detector is expected to be adjacent to the JUNOTAO experiment and to be about 35 m from a reactor core with 4.6 GW thermal power at Taishan.The antineutrino flux is approximately 6×10^(12)cm^(−1)s^(−1) at this location,leading to more than 11,000 coherent scattering events per day in the fiducial mass.Motivation The nuclear recoil energies concentrate in the sub-keV region,corresponding to less than ten ionization electrons in the liquid argon.The key question is how to veto and shield the background in the hall where the vertical overburden is about 5 m.w.e.And what is the signal count rate and the background rate.In addition,what physical parameters can be measured what is the sensitivity.Methods We used the Geant4 to simulate the backgrounds from cosmic ray muons and ambient radioactivity decays.And a veto and shielding design is presented.Then a χ^(2) function is constructed and the sensitivity calculate package built to calculate the sensitivity of physical parameters.Results The detection of several ionization electrons can be achieved in the dual-phase TPC due to the large amplification in the gas region.With a feasible detection threshold of four ionization electrons,the signal rate is 955 per day.The detector is designed to be shielded well from cosmogenic backgrounds and ambient radioactivities to reach a 16%background-tosignal ratio in the energy region of interest.With the large CEvNS sample,the expected sensitivity of measuring the weak mixing angle sin^(2)θ_(w),and of limiting the neutrino magnetic moment are discussed.In addition,a synergy between the reactor antineutrino CEvNS experiment and the dark matter experiment is foreseen.