| The neutron generator is an instrument that generates neutron rays.The neutron generator consists of a neutron tube,a reservoir power supply,an ion source power supply,an acceleration stage power supply,and a control system.It has many advantages such as light weight,mobility,good monochromaticity,no gamma background,safe use,no radiation hazards,etc.It has extensive applications in material element analysis,oil logging and other fields.Traditional neutron generators can only work in DC operating mode.The source of the ion source is Hengbo high-voltage power supply,which has the disadvantages of large size,high cost,and difficult maintenance.With the continuous development of neutron applications,there are more and more applications for pulsed neutrons in recent years.Compared with DC neutrons,more neutron nuclear reaction information can be obtained by irradiating the material with pulsed neutrons.And the application field of pulsed neutron generator is more extensive.The neutrons and substances produced by the pulsed neutron generator can undergo a variety of nuclear reactions to generate characteristic gamma rays such as non-elastic,trapping,and slow-release.In pulsed neutron applications,researchers hope that pulsed neutrons can be rapidly generated and rapidly disappeared,allowing neutron gamma spectroscopy to be spectrally separated to obtain more neutron nuclear reaction information for analysis.To solve these problems,this paper designs a new type of ion source power supply for the pulsed neutron generator console.It can work in both DC and pulse modes to meet the needs of users.DC high-voltage ion source power adopts Buck and push-pull cascading topological structure,using high-frequency high-voltage transformer and Cockroft-Walton voltage doubler rectifier circuit to achieve 0~3000V DC high-voltage output.Buck circuit based on buck regulator chip TPS54360 design,for its internal structure and working principle,a voltage feedback network was designed which makes the regulated power supply formed by this chip capable of starting from zero.The push-pull circuit uses the SG3525 to generate a complementary PWM signal.After the IR4427's enhanced drive capability,the MOSFET is driven.The high-frequency transformer is wound with P22137310 core manufactured by TDK Corporation.The primary input voltage is 0~48V,the secondary maximum output voltage is 500 V,and the operating frequency is 100 kHz.The Cockroft-Walton voltage doubler rectifier circuit consists of a high voltage capacitor and a fast recovery diode.The design uses a three-order,sixfold voltage approach.In addition,the voltage and current sampling circuit is designed by using the resistive voltage divider method and the resistance sampling method.Through experimental verification,the sampling circuit can accurately sample the output voltage and current.This paper designs a small power chopper circuit with 2SD315 A as the drive module.Drive module 2SD315 A can drive the two switch tubes of the upper and lower arm at the same time,achieve half-bridge chopping in the DC high voltage state,and get the pulse high voltage.The module has a rich peripheral interface,and can well communicate with the control chip to obtain the working status and fault information of the chopper circuit.The chopper circuit includes: input protection circuit,undervoltage protection circuit,status indication circuit,and drive protection circuit.The ion source power test results developed in this paper are as follows:in the DC mode,the output voltage is 0~3000V continuously adjustable,the maximum output current is 2 mA,ripple coefficient is 0.85%,the efficiency is up to 89.20%,and the voltage adjustment accuracy is 0.67%;in the pulse mode,the output high-voltage pulse frequency is continuously adjustable from 0 to 20 kHz,the minimum pulse width is 10?s,the rising edge time and the falling edge time are all within 2?s,which satisfies the requirement of pulse neutrons for elemental analysis and has good performance. |
PDF Full Text Request