Spatial and temporal beam profile monitor with nanosecond resolution for CERN's Linac4 and Superconducting Proton Linac
Spatial and temporal beam profile monitor with nanosecond resolution for CERN's Linac4 and Superconducting Proton Linac
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DOI：
10.1016/j.nima.2008.01.078
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发表时间：
2008-04
影响因子：
1.4
通讯作者：
M. Hori;K. Hanke
中科院分区：
文献类型：
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作者：
M. Hori;K. Hanke
欧洲核子研究中心正在开发的LINAC4将提供N=2×1014离子SS-1的160 MeV高强度H束流。在将该束流注入欧洲核子研究中心质子同步加速器或未来的超导质子直线加速器以进一步加速之前，必须使用束流切割器从其中移除一些500 ps长的微束序列。这些束流如果留在束流中，就会落在加速器纵向可接受的范围之外，使它们具有放射性。我们研制了一台监视器来测量这种截断光束的时间结构和空间分布，其分辨率分别为Δt∼1 ns和Δx∼2 mm。它的大有源区40 mm×40 mm和动态范围也可以用来研究束晕。离子束首先击中了碳箔，从碳箔中涌出的二次电子被一系列平行的栅极电极加速。这些电子击中荧光屏，产生的闪烁光图像被引导到热电冷却的电荷耦合设备相机。时间分辨率是通过向栅极施加亚纳秒上升和下降时间的高压脉冲来实现的。该监视器已经使用700 ps长的UV激光脉冲和3 MeV的质子束进行了测试。研究了它在Ne∼5~4×108电子数范围内的响应。该监测器还可用于测量未来低能反质子研究设施(FLAIR)或超低能反质子环(ELENA)设施中的反质子束轮廓。
The Linac4, now being developed at CERN, will provide 160-MeV H-beams of high intensity N=2×1014ionss-1. Before this beam can be injected into the CERN Proton Synchrotron Booster or future Superconducting Proton Linac for further acceleration, some sequences of 500-ps-long micro-bunches must be removed from it, using a beam chopper. These bunches, if left in the beam, would fall outside the longitudinal acceptance of the accelerators and make them radioactive. We developed a monitor to measure the time structure and spatial profile of this chopped beam, with respective resolutions Δt∼1ns and Δx∼2mm. Its large active area 40mm×40mm and dynamic range also allows investigations of beam halos. The ion beam first struck a carbon foil, and secondary electrons emerging from the foil were accelerated by a series of parallel grid electrodes. These electrons struck a phosphor screen, and the resulting image of the scintillation light was guided to a thermoelectrically cooled, charge-coupled device camera. The time resolution was attained by applying high-voltage pulses of sub-nanosecond rise and fall times to the grids. The monitor has been tested with 700-ps-long UV laser pulses, and a 3-MeV proton beam. Its response over a wide range of beam intensities between Ne∼5 and 4×108electrons emitted from the foil per pulse was studied. The monitor can also be used to measure the profiles of antiproton beams in the future facilities of Facility for Low-energy Antiproton Ion Research (FLAIR) or Extra Low Energy Antiproton Ring (ELENA).