Establishment Of （50-125）kV Pulsed X-ray Reference Radiation Field And Study On Its Parameters

In the existing calibration system of China,the continuous X-ray reference radiation field mainly consists of low energy and medium energy,which provides extensive and important services for the society.With the continuous update and development of pulse power technology,the proportion of pulse X ray generating equipment is increasing.Due to the lack of relevant reference radiation field and standard,the problem of pulse X ray condition cannot be quantified traceability appears.In order to solve the problem of dose monitoring and quality control,it is necessary to establish a pulsed X-ray reference radiation field.In this paper,the（50-125）k V pulsed X-ray reference radiation field is established by pulsed X-ray machine,high voltage generator with adjustable frequency and width,cooling system,combined with other regulating equipment and measuring equipment.The tube voltage,tube current,radiation field and pulse stability were measured.Two kinds of pulse signal measurement modules are designed to detect pulse amplitude,pulse width,pulse rising time and falling time.Using commercial ionization chamber,thermoluminescence dosimetry system and optical luminescence dosimetry system,the pulse dose was studied,and the value transfer experiment was carried out on the instrument.The uncertainty in the pulsed X-ray reference radiation field was evaluated.The voltage of pulse X-ray tube is consistent with the nominal value within ±2%,and the ripple voltage is stable within ±0.5k V.At 1m distance from the photomechanical focus,the 99% uniform field diameter was 0.84 cm and the 95%uniform field diameter was 5.80 cm.The maximum scattering fraction of the radiation field is not more than 0.2%,which meets the requirement of 5% of the conventional radiation field.When the pulse width was set in the range of（5-6300）ms,the difference between the measured value and the preset value was within ±0.5ms,and the pulse waveform in this range has reference waveform characteristics.Using TW23361 ionization chamber to determine the air kerma kinetic rate with pulse width of 1000 ms,tube current of 50 m A and different radiation qualities,the range of air kerma kinetic rate with N series radiation is（0.020-0.118）m Gy/s.and the RQR series air kerma kinetic rate range is（1.67-6.17）m Gy/s.According to the evaluation method of uncertainty,the uncertainty of（50-125）k V pulse X-ray reference radiation field is4.6%（k=2）.In summary,the established（50-125）k V pulse X-ray reference radiation field has a certain reference radiation capacity,which can provide calibration services for active instruments and other equipment under the pulse field.The radiation field provides a platform for pulse measurement technology research in related fields in China,and provides data support for the formulation of relevant standards of pulse X-ray for radiation protection.