Measurement of Radioactive Activity in Accordance with Measurement Probe

正The project is to develop a digital coincidence measurement device for radioactive gas activity,applying NaI(Tl)crystal as theγ-ray detector,and internal gas proportional counter as theβ-ray detector.The radioactive gas is filled into the proportional counter and the counter is placed in the NaI(Tl)crystal.     

Analysis of Secondary Neutron Component's Source Term after Discharging

<正>The secondary neutron component can be used as start-up neutron source for commercial nuclear power plant.It's working principle shows as follow.1) Irradiation process:The secondary neutron component is made up with Sb-Be pellets and loaded into the reactor core.It will be irradiated for one cycle.The nuclide~(123) Sb underthe neutron irradiation becomes nuclide~(124) Sb by the radioactivation reaction path (n,γ).2) Decay process:After the secondary neutron component being discharged from the core,the decay gamma ray of~(124) Sb (T_(1/2)=60.20 d) is utilized to react with nuclide~9 Be in Sb-Be pellets to generate photon-neutron by the path of (γ,n).     

Standardization of Tritium Water by TDCR Method

The triple-to-double coincidence ratio (TDCR) method of liquid scintillation count-ing is an absolute measurement method of radioactivity.The formulation of the TDCR method and the established TDCR liquid scintillation counter are presented in this paper.The NIST standard reference material (SRM) of tritium water was measured to verify the performance of the TDCR liquid scintillation counter.     

Design of Neutron Surveillance System in Reactor during the First Loading

正~3He proportional counter has a high detective efficiency and a broad range of energy response over neutron.The dielectric gas in it,~3He,is inactive.Therefore,the detector is quite stable and is acceptable with high temperature.Thus,~3He proportional counter has some inevitable advantages over other detectors,and it’s a     

Research on Control Platform of Multiple Degrees of Freedom

正The whole-body counter,mainly consisted of detectors,the shield and the control platform of multiple degrees of freedom(CPOMDOF),is a comprehensive system for rapid and efficient measurement of radio nuclides absorbed by human.The CPOMDOF is a set of very accurately     

Development of Active Well Neutron Coincidence Counting System

The active well neutron coincidence counter（AWCC） has been developed, which is one of the main devices on non-destructive assay for the U-bearing nuclear material. The AWCC bases on the thermal neutron induced fission of ^235U, and the induced fission neutron source in the device is two Am-Li neutron sources with low energy neutron emitting.     

Half-life of ~(132)I

132I (T1/2≈2.3 h) is a short-lived fission product nuclide. Its half-life is a critical nuclear parameter. In 1950’s, half-life of 132I had been measured with a scintillation counter and a ionization chamber, respectively. The total β or γ radioactive…     

Development of Active Well Neutron Coincidence Counting System

The active well neutron coincidence counter(AWCC) has been developed,which is one of the main devices on non-destructive assay for the U-bearing nuclear material. The AWCC bases on the thermal neutron induced fission of 235U,and the induced fission neutro…     

PRELIMINARY PROGRAMMED WHOLE—BODY COUNTER

It is capable of giving the initial intakes of radionuclides and the assessment quantitites used in radiation protection according to its measured results of radionuclides in vivo.It is accomplished by providing the software of controlling,interface and internal dose estimation programs to the original iron cabin shielding whole-body counter.The preliminary application shows that its data processing is rapid and correct,and can meet the requirement of rapid internal radioactive contamination monitoring and diagnosing in case of lots of internal contamination subjects happened in nuclear accident.     

Calculation of Neutron Induced Reaction on ~(121,123)Sb

A set of neutron optical potential parameters for energy from 0.01 to 20 MeV is obtained on the basis of available experimental data of ~(121,123,Nat)Sb and neighbored nucleus. Based on this set of optical potential parameters, all cross sections of neutron induced reactions for ~(121,123)Sb are calculated. The calculated results reproduce the available experimental data well.     

Current Sharing Analysis of Arm Prototype for ITER PF Converter Bridge

A bridge arm prototype of ITER poloidal field （PF） converter modules has been designed and fabricated. Non-cophase counter parallel connection is chosen as the arm structure of the prototype. Among all factors affecting current sharing, arm structure is the main one. During the design of the arm prototype, a novel method based on inductance matrixes is employed to improve the current sharing of the bridge arm. The test results on the prototype show that the current sharing performance of the arm prototype is much better than relevant design requirement, and that the matrix method is very effective to analyze and solve the current sharing problems of thyristor converters.     

Yield of iodine isotopes from interaction of 47 MeV／u ^12C with ^133Cs

The production cross sections of the iodine isotopes have been measured radiochemically for the interaction of 47 MeV/u 12C with 133Cs,the iodine isotopic yield distribution was deduced from these data and found to be a Gaussian shape.The Gaussian curve peaks in the vicinity of ^124I and has a FWHM of 5.5 mass units.The mass loss of the most probable product,ΔAp=At-Ap,is 9.2 mass units.The area of the yield curve is as high as 111 mb.     

Preliminary Design of Neutron Dose Measurement Device for Cosmic-Ray

In order to be applied in cosmic ray, a device was designed which uses a spherical moderator and two types of proportional counters. One is the spherical counter which is imbedded at the center of the sphere     

Tokamak fusion neutron spectrometer based on PXI bus

In order to realize on-line real-time measurement of dynamic and time-sharing neutron spectrum of HL-2A,a tokamak fusion neutron spectrometer based on PXI bus was developed.It consists of electronics system and eight thermal neutron detectors,namely SP9 3He proportional counter,embedded in eight polyethylene spheres in different diameters.Response function of the eight polyethylene spheres was the key to calculate the neutron spectrum accurately.In this paper,response function of the eight polyethylene spheres is simulated by adopting Geant4 code,and neutron counts from an 241Am-Be neutron source are measured by the eight detectors.The calculated spectrum of the Am-Be neutron is accurate in 0-2 MeV region,and is similar to the theoretical spectrum.The tokamak fusion neutron spectrometer was used in HL-2A device to monitor the dynamic neutron spectrum of HL-2A on-line and real-time.     

Metabolic peculiarity of 134Cs and its radioimmunotoxicological effect on central and peripheral immune cells

A fitted equation with least square method to describe the retention of ^134Cs in whole body is obtained by a whole body counter.That is R(t)=18.04exp(-9.3175t) 45.13exp(-0.0423t),where R(t) is in %,and t in d.The equationn consists of two half-life components,the fast component is T1/2=0.07d,and the slow is T1/2=16.14d,Study on the localization of ^134Cs at cellular level was carried out by freezing microautoradiography.The results indicate of ^134Cs at cellular level was carried out by freezing microautoradiography.The results indicate that ^134Cs was chiefly in ionizing form accumulated in red as well as white blood cells.In bone marrow cells ^134Cs predominantly deposited in young cells and less in mature cells.Distribution of ^134Cs penetrated quickly into the tissue cells.The observation of investigating radioimmunotoxicological effect induced by ^134Cs shows that the inhibition of thymocytes is higher than bone marrow cells,the spleen T lynmphocytes are more sensitive to ^134Cs than B lymphocytes and lymphocytes of peripheral immune cells are more sensitive to radiation than central immune cells.     

NAA OF SOME ANCIENT INDIAN COINS

The radioactivity induced in the coins from satvahanas,Ahmadshah Bahamani,Gujrat Sultan,Nizamshahi and Marathas after(n,γ) reactions for the elements of interest is measured on multichannel analyzer coupled to high purity germanium detector and percentage of these elements is determined by comparator method of NAA.All these coins are found to be copper based with the presence of As,Sb,In,Au,Sn and Mn.     

36Cl-AMS measurements with 3-MV tandem accelerator

36Cl is one of the most interesting nuclides in accelerator mass spectrometry (AMS) measurements. The application of 36Cl has been widely applied in various fields. All most all of 36Cl AMS measurements at natural isotopic concentrations have yet been performed at tandem accelerator with 5 MV or higher terminal voltage. The measure improvement of 36Cl and other medium heavy isotopes performed at 3 MV in AMS facilities is one of the hottest topics in AMS measurements. In order to increase the suppression factor of 36S, the energy loss straggling and angular straggling of 36Cl and 36S ions in various counter gases (P10, isobutane and propane) were investigated. Some groundwater samples were measured with energy of 32 MeV, and the results were in good agreement with the result obtained with ion energy of 72 MeV. The results indicate that the approximate detection limit of 36Cl in 3 MV AMS facility is 36Cl/Cl=1×10-14 , and the uncertainty is 30% when the sample with isotopic ration 36Cl/Cl≈10-13.     

Geant4 simulation of multi-sphere spectrometer response function and the detection of ~(241)Am–Be neutron spectrum

This paper is aimed at detecting the neutron spectrum of~(241)Am–Be, a widely used neutron source, with the SP9 ~3He proportional counter, which is a multi-sphere spectrometer system of eight thermal neutron detectors embedded in eight polyethylene(PE) spheres of varying diameters. The transport processes of a neutron in the multi-sphere spectrometer are simulated using the Geant4 code. Two sets of response functions of the PE spheres are obtained for calculating the~(241)Am–Be neutron spectrum.Response Function 1 utilizes the thermal neutron scattering model G4 Neutron HPThermal Scattering for neutron energies of ≤4 eV, and Response Function 2 has no thermal treatment. Neutron spectra of an~(241)Am–Be neutron source are measured and compared to those calculated by using the response functions. The results show that response function with thermal treatment is more accurate and closer to the real spectrum.     

Simulation and calibration of the response function of multi-sphere neutron spectrometer

In order to realize the on-line real-time measurement of neutron specmnn of ITER fusion, this paper presents a multi-sphere spectrometer system which consists of eight thermal neutron detectors, namely SP9 3He proportional counter, embedded in eight different diameter polyethylene spheres. The response function of eight polyethylene spheres of rnulti-sphere neutron spectrometer was calculated after the simulation of the neutron transport processes in multi-sphere spectrometer by adopting software Geant4. The peak of the response function is in the low energy region for smaller diameter polyethylene sphere. As the polyethylene sphere diameter increased, the peak of the response function moves to the high energy region. The experimental calibration adopts 241Am-Be neutron source. The relative error between normalized data of experiment 47t solid angle counts and normalized data of simulated detection efficiency of 4in to 8in polyethylene sphere is from 1.152% to 12.222%.The experimental results verify the response function of the simulation. All these results provide a theoretical and experimental basis for solving the on-line real-time neutron spectrum of ITER fusion.     

AN APPLICATION OF IPM POTENTIAL IN CALCULATING THE ENERGY STRAGGLING FOR FAST PROTON BEAMS

Energy straggling for fast proton beams in Ni, Al, Ti, Cu, In and Sb solids and N, O, F, B, S, Cl and air gases were calculated using an effective IPM potential which contains an adjustable parameter. The energy and Z_2 (target atomic number) dependence of the energy straggling for proton in materials are Obtained when Bonderup and Hvelplund's formulation is used. The results are compared with some experiments in detail, and show in good agreement with them.