Design Calculations for the An injector of an electron linear accelerator has been modified at ISIR of Osaka University in order to increase a single bunch charge from 14 nC to 60 nC. A 6th subharmonic prebuncher has been replaced with two 12th subharmonic prebunchers and a 6th subharmonic prebuncher which are newly constructed.A one-dimensional disk model has been used to calculate the bunching of the beam and to decide the optimum location of the subharmonic prebunchers.The subharmonic prebunchers are immersed in a solenoidal magnetic field so that the electron beam is confined during the travel through the drift region.The single bunch of 16 -20 ps duration and up to 67 nC in charge, with the energy spread of 0.7 -2.5 % over the range of 24 -34 MeV, and a repetition rate from a single shot to 720 pps can be obtained.The energy spread depends on the charge and the minimum spread is 0.7 % at 33 nC.The single bunch of 25 -45 nC in charge is used for the experiments in routine work.
TSEE glow curves were studied for ion-implanted LiF single-crystals and for crystals irradiated by X-rays as well as those thermally annealed and irradiated by X-rays (afterward). It was found that the TSEE glow curve for Mg+ implanted LiF is influenced by the implantation energy and dose. Also, the annealed Mg+ implanted LiF (100 kV ×1012 Mg+/cm2) showed a greater response upon X-rays irradiation (compared with non-implanted LiF). Variations in the TSEE glow curves are qualitatively discussed.
The trapped electron which absorbs in the visible region in crystalline ice e−vis has been studied by pulse radiolysis in the low temperature range 6 to 77 K using 2 μs pulses, and above 77 K using pulses of 40 ps to 6 ns width. The half-life of e−vis in ice around 77 K is unusually short, 8 ns in H2O ice and 120 ns in D2O ice. The decay of e−vis in ice is found to fit Hummel’s empirical equation for the decay by geminate ion recombination in a spur. Several other pieces of evidence indicate that the decay occurs in a spur. Electron tunneling from e−vis to the OD radical does not occur in D2O ice. It is concluded that a proton (H3O+) or a deuteron (D3O+) produced in a spur by the irradiation migrates through ice to react with immobile e−vis in the same spur, and that the half-life of e−vis is determined by the mobility of the proton or deuteron. The Arrhenius plot of the half-life in the range 100 to 6 K is nonlinear and shows an activation energy of 20 meV at higher temperatures and much smaller values at temperatures below 50 K (1 meV below 15 K). The causes of the unusual Arrhenius plot and the isotope effect on the proton mobility are discussed.
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