CONSTRUCTION OF AN IN-VACUUM TYPE UNDULATOR FOR PRODUCTION OF UNDULATOR X-RAYS IN THE 5-25 KEV REGION

A new 179-pole undulator with magnetic period of 4 cm for production of brilliant and quasimonochromatic hard x rays has been completed and installed in the TRISTAN Accumulation Ring (AR) in KEK, National Laboratory for High Energy Physics. The aperture of the undulator for the circulating electron can be flexibly changed to satisfy the operational requirements of AR, since the undulator magnets are encased in the vacuum chamber of the undulator. When it is operated at the magnet gap of 20 mm with 6.5-GeV operation of AR, intense 14.4-keV radiation for Mossbauer experiments is successfully obtained as the third harmonic of the undulator radiation.