R & D of a Cosmic Ray Detector with Proton Beams by CERN-SPS

我们对球载光纤电子望远镜（BETS）进行了加速器束流测试。探测器被转移到瑞士的CERN，并被照射到能量从30 GeV到250 GeV的质子束。这个能量区域对应于我们观察到宇宙射线电子的能量区域。该望远镜能够通过对簇射发展的成像来识别电子和测量能量。近10万个质子在各种条件下被辐照，数据被记录在数字记录磁带上。实验是在CERN工作人员的大力支持下完成的。试验目的在预定日期内完全完成。通过对实验数据的分析，我们证实了BETS的如下性能：通过对簇射剖面的成像，可以实现对质子的抑制。很明显，来自探测器一侧的质子也可以作为背景被触发，并且可以通过分析被拒绝。对质子的排斥功率与模拟结果一致，采用质子排斥功率，我们从1997年和1998年的气球数据中明确地导出了电子能谱。利用束流测试结果，将发展一种提高抑制功率的新方法。

We have carried out accelerator beam tests for the balloon-borne electron telescope with scintillating fibers (BETS). The detector was transferred to CERN in Switzerland and was irradiated to the proton beams with energies from 30 GeV to 250 GeV.This energy region corresponds to the energy region in which we observed the cosmic-ray electrons. The telescope is capable to identify the electrons and measure the energies by imaging the shower developments with scintillating fibers.The beam tests were carried out at the SPS-T1/X5 beam line in the West Area. Nearly 100 thousands protonns were irradiated under various conditions and the data were recorded, on the digital recoding tapes. The experiment was performed by excellent supports by the CERN staffs. The purpose of the test was completely accomplished within the scheduled dates. By the data analysis, we have confirmed the performance of BETS as following :.The rejection of protons can be performed tby imaging the shower profile..It becomes clear that the protons coming from the side of detector can also be triggered as backgrounds and can be rejected by analysis..The rejection power against the protons is consistent with simulation.We have definetly derived an electron energy spectrum from the balloon data in 1997 and 1998 by adopting the proton rejection power. A new method for higher rejection power will be devldped using the beam test results.