A Real-time System For Measuring Spot Size of High Energy Accelerator Using Thick Pinhole Imaging

In order to easily measure the beam spot size of high energy electron accelerators with internal target enclosed,a real–time system, based on thick pinhole imaging technique, is employed. The experimental result on a 15MeV electron linear accelerator is also presented. In this paper the principle of thick pinhole imaging and the processing of data are introduced. The usual "sandwich" method needs to develop X-ray films, while debugging the accelerator parameters it will take a lot of time. On the contrary, X–ray pinhole imaging method can make a real–time measuring: as the accelerator parameters change, we can observe the beam profile's variation on the computer screen. Then when debugging we can have a definite object in view, and adjust the accelerator parameters more efficiently.