Institutional Repository of Institute of Modern Physics, CAS
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Longitudinal dynamics of RF-bunched and electron-cooled ion beam at the CSRe
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">The longitudinal dynamics of RF-bunched and electron cooled ion beams have been studied at the experimental cooler storage ring (CSRe), at IMP Lanzhou, By RF-bunching the ion beam at the 50th and 100th harmonic of the revolution frequency, the longitudinal momentum spread and the bunch length of the Ne-22(10+) ion beam with an energy 70 MeV/u were measured by the new resonant Schottky pick-up and the capacitive pick-up, respectively. A minimum momentum spread of Delta p/p = 1.6 x 10(-5) has been reached with less than 10(7) ions stored in the ring. By using the harmonic potential extracted from the Taylor expansion and the real sinusoidal potential of the bucket, the trend of momentum spread and synchrotron frequency as well as the bunch length as a function of beam current can be interpreted very well. According to this experiment, the RF-buncher is suitable for upcoming experiments on laser cooling of relativistic heavy ion beams at the CSRe. (C) 2013 Elsevier B.V. All rights reserved.</span
Design of a compact structure cancer therapy synchrotron
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">HIMM, a new compact accelerator facility dedicated to carbon cancer therapy, has been designed and is presently under construction. The synchrotron has a compact structure that exhibits a circumference of only 56.2 m. The charge exchange injection (CEI) method is adopted for synchrotron injection with a carbon-ion energy of 7 MeV/u. The third-order resonance and RE-Knock Out scheme are adopted in this machine. The general design of the machine and injection/extraction simulation results is discussed in this paper. (C) 2014 Elsevier B.V. All rights reserved.</span
Simulation of direct plasma injection for laser ion beam acceleration with a radio frequency quadrupole
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">The direct plasma injection scheme (DPIS) has been being studied at Institute of Modern Physics since several years ago. A C6+ beam with peak current of 13 mA, energy of 593 keV/u has been successfully achieved after acceleration with DPIS method. To understand the process of DPIS, some simulations have been done as follows. First, with the total current intensity and the relative yields of different charge states for carbon ions measured at the different distance from the target, the absolute current intensities and time-dependences for different charge states are scaled to the exit of the laser ion source in the DPIS. Then with these derived values as the input parameters, the extraction of carbon beam from the laser ion source to the radio frequency quadrupole with DPIS is simulated, which is well agreed with the experiment results. (C) 2014 AIP Publishing LLC.</span
Study on a negative hydrogen ion source with hot cathode arc discharge
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">A negative hydrogen (H-) ion source with hot cathode arc discharge was designed and fabricated as a primary injector for a 10 MeV PET cyclotron at IMP. 1 mA dc H- beam with (epsilon) N, RMS = 0.08 pi mm mrad was extracted at 25 kV. Halbach hexapole was adopted to confine the plasma. The state of arc discharge, the parameters including filament current, arc current, gas pressure, plasma electrode bias, and the ratio of I-e-/I-H- were experimentally studied. The discussion on the result, and opinions to improve the source were given. (C) 2013 AIP Publishing LLC.</span
Dragon's blood and its extracts attenuate radiation-induced oxidative stress in mice
No full textDragon's blood (DB) possesses great medicinal values due to the presence of several phenolic compounds. This study was designed to investigate the effects of DB and its extracts (DBEs) on oxidative stress in mice exposed to whole body Co-60-gamma irradiation (4 Gy). DB and DBEs were intragastrically administered to mice for 5 d prior to radiation. The antioxidant activities, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) levels in liver and spleen were measured using kits. Furthermore, DB and DBE effects were determined by organ indices and histology of liver and spleen. Our results indicated that the DB and DBE-treated groups showed a significant decrease (P < 0.05) in levels of MDA in liver and spleen compared with the irradiation-only group. Moreover, the activity of SOD, CAT and the level of GSH in liver and spleen tissue were enhanced significantly (P < 0.05) in the DB and DBE groups. DB and DBE also had a significant effect on the recovery of thymus indices. The histological observations of groups having treatment with DB and DBE indicated significant reduction in the radiation-induced damage to the liver and spleen, together with improvement in the morphology of the liver and spleen. These results suggest that DB and DBE treatment prevents radiation-induced oxidative stress injury and restores antioxidant status and histopathological changes in the liver and spleen, but there is need for further study to explore the precise molecular mechanism and strategy for optimal practical application of DB and DBE