The Measurement And Research Of (170-300)keV Monoenergetic X-rays

After decades of development,Space astronomy has achieved fruitful results in astronomical abservation.It is also expanded human understanding of the universe.The energy linear,detection efficiency,energy resolution and homogeneity are important parameters of the detector.We can simulate real situations with detection data only if we calibration the detector.Thus,it is very important for us to calibrate the detector accurately.Usually,we use radionuclide to calibrate detectors,but the preparation of radionuclide is difficult,and there is only a few branches of energy we can use.This paper carried out the research of monoenergetic X-rays that created by X-xay tube and monochromator.The energy range of Hard X-ray Calibration Facility(HXCF)in National Institute of Metrology(NIM)in Beijing is about(15-168)keV.On that basis,we use a new X-rays tube with higher voltage,transform the configuration of monochromator,design and process a new mobile system.Eventually,the energy range of HXCF has been extended.We measured the parameters of the X-rays facility all sided,details are as follows:(1)The X-ray tube with 600 kV voltage is the most important equipment foundation of the whole facility.We measured the tube voltage,current and the inherent filtration,it tured out that the facility can display the real voltage in ± 1%,it’s satisfied the requirement for reference radiation devices in GB/T12162.1-2000.The current and radiant quantity of the X-ray tube have a very good linear relationship,the correlation coefficient is almost 1.The inherent filtration of the X-ray tube is equivalent to 0.146 mm Al.(2)We transform the configuration of monochromator.The energy range of the facility has been expanded to 300 keV.The anode target of the X-ray tube is tungsten.The energy spectrum of the tube is a continuous spectrum,it’s not suitable for calibration.The monochrmator is somposed by a piece of crystal and a high precision turntable,it can divide the incidence continuous energy to a monoenergetic one.We use the Si(551)crystal and obtained the monoenergetic X-rays from 37.6 keV to 310.3 keV.(3)We measured the energy,fluence,monochromaticity and stability of the facility all-sided.We use the GEM detector measured the spot size of the facility,through analyzing the test data,the result show the spot size is about 6mm.Mutual verify through simulation and experiment,we get the detection efficiency of HPGe.Then,we measured the absolute photon number.Through analyze the spectrum,the monochromaticity of X-rays gradually decreases with the increase of energy(better than 5%).We also measured the stability in 50 hours,the energy stability is 0.47%,and the stability of beam intensity is 1.38%.This research expand the energy range of the X-ray facility.The facility provide good condition for the calibration of detectors that need higher energy.The decive has a wider application prospect.