Upgrade plan of Laser Undulator Compact X-ray source (LUCX) (1)

We have developed a compact X-ray source via inverse Compton scattering between an electron beam and a laser pulse stacked in an optical super-cavity at Laser Undulator Compact X-ray (LUCX) accelerator in KEK. The accelerator consists of a photo-cathode RF-gun and an S-band accelerating tube and now produces the multi-bunch electron beam with 100 bunches, 0.4nC bunch charge and 30-40MeV beam energy. In the autumn of last year, we have succeeded in taking X-ray images of fish bone and etc. However, it took two hours to get an X-ray image because of low intensity of X-ray with the number of 104 photons/pulse. To get a clear image at shorter times, we are planning to increase the intensity of X-ray to 450 times. To achieve this aim, the number of bunches of the electron beam is extended to 1000 bunches and the stacked power in the laser cavity is increased to 15 times by expanding the laser size on the mirror in order to avoid the mirror damage. Moreover, the collision angle is reduced to 6 degree. By doing so, the expected number of X-ray is 1.7×107photons/pulse. In this upgrade, a 3.6cell rf-gun, a 12cell booster and a planner type four-mirror Cavity will be introduced. In this paper, the upgrade of this accelerator will be reported. (author)