SPring-8 tests its superconducting wiggler

A three-pole 10 T wavelength shifter (wiggler) has recently been installed and tested on the 8 GeV SPring-8 with the aim of investigating the scope of SPring-8 as a γ-ray source in the 1–5 MeV range. A beam of 1 mA (limited to this value to avoid excessive heat load) has been stored at wiggler magnetic fields of up to 9.7 T. The superconducting wiggler spectum showed very high intensity in this range in accordance with the calculated spectrum. A significant effect on the stored beam, namely an increase in horizontal emittance by a factor of two, was observed. It is likely that if this device is to become an experimental facility then it would be used in its own dedicated time with small beam currents in the storage ring.