RESUMO
SPring-8 is a third-generation synchrotron radiation source operating in the soft and hard X-ray region. It consists of an injector linac of 1 GeV, a booster synchrotron of 8 GeV and a storage ring with a natural emittance of 5.9 nm rad. The storage ring can accommodate 61 beamlines in total, and 26 of them are under construction. The project has been carried out jointly by JAERI and RIKEN and construction of the facility started in 1991. Commissioning of the injector linac was started in August 1996 and an 8 GeV electron beam was injected into the storage ring in March 1997. The first synchrotron radiation from a bending magnet was observed at the front end of the beamline on 25 March and radiation from an undulator was observed on 23 April. On-beam testing of seven beamlines, four of them from in-vacuum undulators and three from bending magnets, started in July. The maximum stored current is currently fixed at 20 mA and the lifetime at maximum current is longer than 20 h. The dedication is scheduled for October 1997.
RESUMO
A low-energy positron beam is a unique probe of materials. In high-energy electron and positron storage rings it is possible to generate intense synchrotron radiation with a photon energy of 1-3 MeV by installing a high-field (8-10 T) superconducting wiggler. High-energy photons are converted to low-energy positrons by using a suitable target-moderator system. For an 8 GeV electron storage ring at a beam current of 100 mA, final yields are estimated to be about 10(8)-10(10) slow-e(+) s(-1) or larger depending on the moderation efficiency, with the size of the positron source 10(1)-10(2) cm(2). In the present work a wiggler magnetic system of 10 T is proposed. The main parameters of the superconducting wiggler are presented.
RESUMO
A low-energy positron beam is a unique probe of Fermi surfaces, defects, surfaces and interfaces. In high-energy electron and positron storage rings (E > 6 GeV) it is possible to generate intense synchrotron radiation with 1-3 MeV photons by installing a high-field superconducting wiggler. The strength of the wiggler should be ~8-12 T. High-energy photons are emitted from the wiggler and converted to low-energy positrons by using a suitable target-moderator system. For an 8 GeV electron storage ring at a beam current of 100 mA, final yields are estimated to be ~10(10)-10(12) (slow-e(+) s(-1)) with the size of positron source ~10(2)-10(3) cm(2). The possibility of increasing the brightness of the low-energy positron beam is discussed. Advantages of using synchrotron radiation for producing positrons are pointed out. The effect of a superconducting wiggler on the stored electron beam is also discussed.
