A microbeam slit system for high beam currents

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• 作者：T. Vallentin ; M. Moser ; ^{marcus.moser@unibw.de" class="auth_mail" title="E-mail the corresponding author} ; S. Eschbaumer ; C. Greubel ; T. Haase ; P. Reichart ; ^{patrick.reichart@unibw.de" class="auth_mail" title="E-mail the corresponding author} ; T. Rö ; sch ; G. Dollinger
• 关键词：Microbeam slit system ; Multicusp source ; Fluorescent nuclear track detector ; FNTD
• 刊名：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
• 出版年：2015
• 出版时间：1 April 2015
• 年：2015
• 卷：348
• 期：Complete
• 页码：43-47
• 全文大小：677 K

文摘

A new microbeam slit system for high beam currents of 10 μA was built up to improve the brightness transport of a proton beam with a kinetic energy of up to 25 MeV into the microprobe SNAKE.

The new slit system features a position accuracy of less than 1 μm under normal operating conditions and less than 2 μm if the beam is switched on and off. The thermal management with a powerful watercooling and potential-free thermocouple feedback controlled heating cables is optimized for constant slit aperture at thermal power input of up to 250 W. The transparent zone is optimized to 0.7 μm due to the use of tungsten formed to a cylindrical surface with a radius r=$r=$ 100 mm and mechanically lapped surface to minimize small angle scattering effects and to minimize the number of ions passing the slits with low energy loss. Electrical isolation of the slit tip enables slit current monitoring, e.g. for tandem accelerator feedback control.

With the ability to transport up to 10 μA of protons with the new microslit system, the brightness B_exp$B_{\text{exp}}$ transported into the microprobe was increased by a factor of 2 compared to low current injection using the old slit system.