RECENT DEVELOPMENTS ON ALICE (ACCELERATORS AND LASERS IN COMBINED EXPERIMENTS) AT DARESBURY LABORATORY

Abstract Progress made in ALICE (Accelerators and Lasers In Combined Experiments) commissioning and a summary of the latest experimental results are presented in this paper. After an extensive work on beam loading effects in SC RF booster and linac cavities' conditioning, ALICE can now operate in full energy recovery mode at a bunch charge of 40pC, a beam energy of 27.5MeV and train lengths of up to 100µs. This improved operation of the machine has resulted in generation of coherentlyenhanced broadband terahertz radiation with an energy of several tens of microjoules per pulse and in successful demonstration of the Compton Back-Scattering x-ray source experiment. Experiments on the exposure of living cells to terahertz radiation have been started. These and other developments on ALICE are reported. MACHINE STATUS ALICE, an energy-recovery superconducting linac GaAs photocathode lifetime is now sufficiently long for routine ALICE operation at 40pC. Normally cathode recaesiation is performed once a month, when the quantum efficiency decreases from initial ~3% to below ~0.5%. Over the past year, a number of changes in gradient settings of SC cavities (booster and main linac) were made with the aim of optimising the RF set up and to accommodate limitations presented by the RF system. Each of these variations required significant changes in the overall machine set up. It can now be routinely operated at 27.5MeV with the total beam losses not exceeding 5 to 7%. The energy spectrum of the beam exiting the first cavity of the booster (BC1) with the second cavity (BC2) switched off (resulting in a beam energy of 3.9MeV, compared to the nominal injector energy of 6.5MeV) is shown i

Laboratory manual and notebook to accompany Beginning chemistry and its uses

Mode of access: Internet

Beginning chemistry and its uses

Mode of access: Internet