Direct high power laser diagnostic technique based on focused electron bunch

In laser produced plasma EUV source, high intensity pulse CO<inf>2</inf> laser is essential for plasma generation. To achieve high conversion efficiency and stable EUV power, we desire to measure laser profile at the collision point. However, focused laser profile has not been observed directory by existing techniques. We have been developing laser profiler based on laser Compton scattering. Laser profile can be measured by scanning focused electron beam while measuring Compton scattering signal. This method is suitable for a high intensity laser, but very small spot size of electron beam is required. To achieve small spot size, we use S-band photocathode rf gun and specially designed solenoid lens. The beam size was simulated by General particle tracer (GPT) and directory measured by Gafchromic film HD-810. We have succeeded in observing minimum beam size of about 20μm rms. We are preparing beam scanning system, pulse CO<inf>2</inf> laser and a detector for Compton signal. In this conference, we will report the results of focused electron beam measurement and future prospect.