The Research And Establishment Of K Fluorescent X Ray Radiation Device

With the development of nuclear energy and nuclear technology application, radiation protection and monitoring instruments can improve performance of spectrum measurement, put forward higher requirements on the corresponding calibration instrument. The photon energy range of the reference radiation 8keV~100keV, fluorescent X ray reference radiation with good monochromaticity, high dose rate, energy and other characteristics, in radiation protection instruments are widely used in calibration, the energy response spectrum low energy energy calibration and protective material shielding performance test work. In addition to radiation protection utility based instrument calibration, including fluorescent reference radiation, can spectrum information, to obtain accurate air kerma, average energy and air kerma to dose equivalent conversion coefficient.Fluorescent X ray reference radiation is to stimulate specific radiator material through the primary rays, produce a series of characteristic X ray including K alpha, K beta and L. To K uptake between the margin between radiator K alpha and K beta line materials for secondary filter, eliminate line L and reduce beta K with respect to K alpha line intensity, and to obtain high purity K alpha X-ray fluorescence. Usually require the fluorescence radiation field of the air kerma rate and purity are high enough. Fluorescence radiation quality depends on three factors: the primary radiation source X-ray tube voltage, the thickness of radiator and secondary filter material.This topic is mainly aimed at the low energy photon, combined with the requirements of the international standard ISO-4037, and the establishment of the low energy photon reference radiation field based on fluorescence. In this paper, the research content of the following five aspects of detailed introduction: 1, the Monte Carlo simulation radiation substance to produce fluorescence reference radiation field primary note the amount of energy spectrum and scattering ratio, radiation beam radius; fluorescence yield with the changes of the thickness of the radiator. 2, analog added secondary filtration of secondary injection amount of energy spectrum, radiation field distribution, calculated the best fluorescence purity; radiator surface fluorescence distribution to verify the fluorescence device. 3, primary filtration, the primary aperture, radiator, secondary filter, sub aperture, a collector, and a shielding box fluorescent device composed of fluorescence device research establishment process; 4, low energy and high purity germanium measured the radiation quality primary and secondary to spectra with simulated comparison to verify the correctness of the Monte Carlo model, using root fitting procedure to determine the spectrum energy and energy resolution. 5 matrix ionization chamber to find out the center point of the fluorescent reference radiation field, Raysafe X2 to measure the radiation uniformity radiation beam radius and MC alignment results consistent; independent research and development GEM detector to measure the radiation field of the spot, refers to the influence the type ionization chamber measurements verify the X-ray optical voltage and current on the radiation field.Above work completed to achieve the main technical indicators are as follows: 1, through the Monte Carlo MCNP simulation to solve the theory can not calculate the radiator, a secondary filter optimum thickness value problem. 2 the contribution of the scattering radiation of the device is only 0.05%, the reference radiation field 30 cm and 50 cm is 11 cm, 19 cm, and the fluorescence purity of the single energy can reach more than 94%. 3. Implementation of the seven groups of radiation matter can reference radiation field, test and measurement of the radiation field energy spectrum, stability, radiation beam, the beam size, provide metrology support for low-energy nuclear radiation detector, dose instrument.