Physical designing of the pre-chopper in CSNS LEBT is carried out, which includes the deflecting voltage, the length and the width of the deflecting plates, and the gap between the deflecting plates. The most outstand...Physical designing of the pre-chopper in CSNS LEBT is carried out, which includes the deflecting voltage, the length and the width of the deflecting plates, and the gap between the deflecting plates. The most outstanding feature of the design is that both the gap and the width vary with the beam envelope size. So both the requried deflecting voltage and the loaded capacitance are lowered. In order to avoid destruction of the space charge neutralization by the pre-chopper in the whole LEBT, an electron-trapping electrode is arranged to confine the electrostatic field of the pre-chopper to the local area. To examine the reliability of the pre-chopping design in CSNS LEBT, a similar pre-chopping design in ADS RFQ LEBT is set up and an experiment on the pre-chopper is prepared. 3-dimensional simulations are carried out to determine the loaded capacitance and the applied voltage of the electron-trapping electrode.展开更多
The China Spallation Neutron Source (CSNS) front end incorporates a pre-chopper in the Low Energy Beam Transport line (LEBT) that will remove a 530 ns section of beam at approximately 1 MHz rate, which is the RF frequ...The China Spallation Neutron Source (CSNS) front end incorporates a pre-chopper in the Low Energy Beam Transport line (LEBT) that will remove a 530 ns section of beam at approximately 1 MHz rate, which is the RF frequency of the ring at injection. It's one of the most critical devices for properly controlling the injecting beam loss. Physical designing of the pre-chopper is carried out, and the RFQ itself is used as the beam dump of the chopper system. In order to examine the reliability of the pre-chopper design, the beam study of a similar chopper system is successfully performed. The results of physical design and experiments are presented.展开更多
Introduction Operation target beam power of China Spallation Neutron Source(CSNS),as the China's first 100 kW beam power pulsed neutron source,is now larger than 80 kW.During the beam power upgrading process of CS...Introduction Operation target beam power of China Spallation Neutron Source(CSNS),as the China's first 100 kW beam power pulsed neutron source,is now larger than 80 kW.During the beam power upgrading process of CSNS to 50 kW from 2018 to 2019,many improvements have been made for the front end of CSNS.Results The improvements mainly focus on solving the problems of ion source instability and the radio frequency quadrupole(RFQ)sparking caused by the pre-chopped beam into RFQ.展开更多
文摘Physical designing of the pre-chopper in CSNS LEBT is carried out, which includes the deflecting voltage, the length and the width of the deflecting plates, and the gap between the deflecting plates. The most outstanding feature of the design is that both the gap and the width vary with the beam envelope size. So both the requried deflecting voltage and the loaded capacitance are lowered. In order to avoid destruction of the space charge neutralization by the pre-chopper in the whole LEBT, an electron-trapping electrode is arranged to confine the electrostatic field of the pre-chopper to the local area. To examine the reliability of the pre-chopping design in CSNS LEBT, a similar pre-chopping design in ADS RFQ LEBT is set up and an experiment on the pre-chopper is prepared. 3-dimensional simulations are carried out to determine the loaded capacitance and the applied voltage of the electron-trapping electrode.
基金supported by the National Natural Science Foundation of China (Grant No. 11105166)
文摘The China Spallation Neutron Source (CSNS) front end incorporates a pre-chopper in the Low Energy Beam Transport line (LEBT) that will remove a 530 ns section of beam at approximately 1 MHz rate, which is the RF frequency of the ring at injection. It's one of the most critical devices for properly controlling the injecting beam loss. Physical designing of the pre-chopper is carried out, and the RFQ itself is used as the beam dump of the chopper system. In order to examine the reliability of the pre-chopper design, the beam study of a similar chopper system is successfully performed. The results of physical design and experiments are presented.
文摘Introduction Operation target beam power of China Spallation Neutron Source(CSNS),as the China's first 100 kW beam power pulsed neutron source,is now larger than 80 kW.During the beam power upgrading process of CSNS to 50 kW from 2018 to 2019,many improvements have been made for the front end of CSNS.Results The improvements mainly focus on solving the problems of ion source instability and the radio frequency quadrupole(RFQ)sparking caused by the pre-chopped beam into RFQ.
