Study of pulsed jet operation for beam gas curtain monitors

A beam gas curtain (BGC) monitor was installed in the LHC for continuous transverse beam profile and emittance measurement. A molecular gas curtain was injected into the LHC continuously. In this work, a pulsed gas jet operation was proposed to minimize the introduction of gas molecules to the beam line and optimize the background pressure. The study was conducted on a gas curtain beam profile monitoring system using nitrogen gas. In this case, the pulse gas jet mechanism enables controlled gas injection into the multiple skimmer chamber to generate a supersonic pulse gas curtain. To achieve maximum current intensity and minimum chamber pressure, key parameters were optimized such as pulse duration or duty cycle, nozzle-skimmer distance, and inlet gas pressure. The results demonstrate a well-tuned pulse jet system can significantly reduce background and enhance the signal-to-noise ratio to monitor a pulse beam. The proposed study exhibits potential applications for beam diagnosis, especially for medical accelerators and laser based linear accelerators.