Lifang Wang

Peking university superconducting accelerator facility for free electron laser

Peking University Superconducting Accelerator Facility (PKU-SCAF) is to generate high-quality electron beams with high average current. It is mainly composed of a DC-SC photocathode injector and a superconducting accelerator. It will operate in CW mode. The energy of the electrons is 20–35 MeV and the emittance is o15p mm mrad. PKUSCAF will be used for Free Electron Lasers. r 2002 Elsevier Science B.V. All rights reserved. PACS: 41.85.Ar; 41.60.Cr

Researches on new photocathode for RF electron gun

Abstract Semiconductor photocathode and metal photocathode have different properties. To consider the properties of both, we studied a new type of photocathode – ion implanted photocathode. Cesium ions are implanted into a metal substrate. A photocathode preparation chamber is set up to make this photocathode. A cesium ion source is attached to the common photocathode preparation chamber. In the past two years, we finished making this photocathode and did research on its properties. A series of experiments have been done with different metal substrates, implanting dosages and implanting energies, in order to get a kind of photocathode material with high quantum efficiency and good stability. An increase of quantum efficiency after implantation has been observed. A more interesting result is that the emission spectrum becomes broader.

Research and experiments on niobium-sputtered superconducting QWR in Peking University

R&D on SC quarter wave resonators (QWRs) for heavy ion linacs were initiated in China several years ago. A DC bias-voltage sputtering technology was developed in Peking University for niobium-coated copper QWR. A niobium-sputtered copper QWR with good niobium films was successfully made in October 1999. Low temperature experiments were carried out from November 1999 to September 2000. The accelerating gradient of 5/spl sim/6 MV/m can be obtained with no beam load at 4.2 K. The QWR is installed after the 2/spl times/6 MV tandem and is used to accelerate proton beams. The accelerating gradient of 3 MV/m was obtained with a proton beam load.

Research on Peking University Superconducting Accelerator Facility (PKU-SCAF)

Peking University Superconducting Accelerator Facility (PKU-SCAF) is under development now. This facility is mainly composed of a DC-SC photocathode injector and a main accelerator with 9-cell cavity. It will provide high quality electron beams with 1 mA average current and 20 MeV energy.