R＆D of the High Momentum Beam Line at the High Intensity Proton Accelerator Facility

1.我们已经提交了两份在日本质子加速器研究中心（J-PARC） 50-GeV同步加速器上的实验方案。一个使用10^9/秒的质子束，另一个使用10^<12>/秒的质子束。特别是前一种实验需要在实验目标处的小尺寸光束。如下所述，使用弯曲硅晶体的光束偏转是高动量束流线分支装置的一种很有前途的方法，它可以从10^<14>/sec的主束中产生约10^<10>/sec的质子分支，并且束的尺寸很小。这尤其适用于前一种实验。利用通道效应，在高能加速器研究组织（KEK-PS）的12 gev质子同步加速器和广岛大学的参考150 mev电子环上测试了硅晶体对质子和电子束的偏转方法。KEK-PS的测试实验表明，使用弯曲的硅晶体，大约10^7/秒的质子束从10^<12>/秒的主质子束分支出来。采用这种方法有可能使分支装置处的光束损耗降低约一个数量级。为了在像J-PARC这样的高强度质子设施中构建一个现实的高动量束流线装置，我们需要进一步研究冷却、辐射损伤、可维护性等问题。此外，晶体引起的电子偏转可能导致国际直线对撞机的准直系统。目前正在考虑进行国际合作来调查这些问题。

1.We have submitted two proposals for experiments at the 50-GeV synchrotron of J-PARC, Japan Proton Accelerator Research Complex. One uses 10^9/sec proton beams, and the other uses 10^<12>/sec proton beams. Especially, the former experiment needs small size beams at the experimental target. As described below, the beam deflection using bent silicon crystals is a promising way for a branching device for the high momentum beam line, which makes a branch of about 10^<10>/sec protons from the main beam of 10^<14>/sec, with a small beam size. This is especially suitable for the former experiment.2.A deflection method with silicon crystals for proton and electron beams, utilizing the channeling effect, were tested at the 12-GeV proton synchrotron of the High Energy Accelerator Research Organization (KEK-PS) and at the REFER 150-MeV electron ring of Hiroshima University. The test experiment at KEK-PS demonstrated that about 10^7/sec proton beam was branched from the main proton beam of 10^<12>/sec, using a bent silicon crystal. There is a possibility that the beam loss at the branching device would be reduce by about one order with this method.3.In order to construct a realistic device for the high momentum beam line at the high intensity proton facility like J-PARC, we need to further investigate more issues such as cooling, radiation damage, maintenancibility, etc. In addition, electron deflection by a crystal might lead to a collimation system at the International Linear Collider. An international collaboration to investigate these issues is now under consideration.