Development of a detector for a two-dimensional type beam profile monitor with the use of high intensity beams

研制了一种二维型梁廓形监测仪，在不破坏梁的情况下成功地测量了梁廓形。这些试验用的光束与近红外HIMAC的注入光束配合使用，其能量为6MeV/u，脉冲持续时间为5 ~ 800微秒，离子种类为碳、氧、氖，完全剥离。光束强度是10的第十一阶脉冲。目标为氮气射流片，其厚度为2或5mm，宽度为60mm（平整），密度为le- 3pa。激光束与氮片的碰撞作用，产生波长近400nm的可见光发射，由下方探测器探测到。上述光束条件对应于任何GeV级高强度加速器的光束作用情况的十分之一。探测器采用图像增强器（II）和由拾音器（HARP）组成的高增益摄像机。用几十次脉冲平均测量法确定了光束轮廓。结果表明，在J-PARC MR等高强度光束（设计强度为4e13质子par束）下，在几个束的时间内，将能够探测到光束的轮廓。在设备研制中，在总剂量为1 ~ 5MGy的伽马射线照射下，检测了II的辐射损伤点，并将这些材料改为辐射硬度材料。为了避免大气中氮气的光发射，在真空室中设置了低损耗的检测光学元件。光从II到HARP相机的传输使用辐射硬度型捆扎成像光纤。II采用远程高压转移操作。

A tow-dimensional type beam profile monitor was developed, and beam profiles were successfully measured without destruction to beams. The beam for these tests were used with injection beams for NIRS HIMAC, of which energy of 6MeV/u, pulse duration of five to eight hundreds micro second, and ion species of carbon, oxygen, and neon with fully stripped. The beam intensity was an order of 10 to the eleventh par pulse. The target was a nitrogen gas jet sheet, of which thickness of 2 or 5mm, width of 60mm (flattened), and density of le-3 Pa. The action of collision between beam and nitrogen sheet, visible light emission of which wave length of almost 400nm is occurred, and which is detected by below detector. Above beam conditions was corresponding to one-tenth in the case of the beam action with any high intensity accelerator of GeV class. The detector was employed an image intensifier (II) and high gain video camera consists of pickup tube (HARP). Beam profiles were confirmed measuring with several ten pulses averaging. This results shows that with high intensity beams (design intensity: 4e13 proton par bunch) such as J-PARC MR, within a time of several bunch, beam profile will be able to detect.In equipment developments, with gamma ray exposure as total dose was 1 to 5MGy, II' s radiation weal points were examined, and the these materials were changed to radiation hardness materials. Avoiding to an emission of light by nitrogen in atmosphere, detection optics with low loss was set in a vacuum chamber. Light transportation from II to HARP camera was done using a radiation hardness type bundled image fibers. And II was operated by remote high voltage transfer.