R & D of a Cosmic Ray Detector with High Energy Beams at CERN

我们对具有闪烁纤维的气球载电子望远镜进行了加速器束测试。探测器被转移到瑞士的欧洲核子研究中心，并被能量从5GeV到100GeV的电子束照射。这个能区对应于我们观测宇宙线电子的能区。该望远镜能够识别电子，并通过用闪烁的纤维成像簇射发展来测量能量。束流测试是在西区的SPS-T1/X5束线上进行的。在各种条件下照射了近20万个电子，在数字记录磁带上记录了大约5千兆字节的数据。实验是在CERN工作人员的大力支持下进行的。通过对实验数据的分析，我们确定了以下的实验结果：通过对簇射廓线的成像，成功地实现了电子的选择。能量分辨率在15%到18%的范围内，角度分辨率约为1度。我们利用定标结果，成功地从1995年和1997年的气球数据中推导出了电子能谱。我们将通过质子束实验来确定拒绝功率，并开发分析方法，以获得对质子更高的拒绝功率。

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 electron beams with energies from 5 GeV to 100 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 200 thousands electrons were irradiated under various conditions and about 5 GBytes data were recorded on the digital recording 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 selection of electrons is successfully performed by imaging the shower profile.The energy resolution is in the range of 15% to 18%.The angle resolution is about 1 degree.We have successfully derived an electron energy spectrum from the balloon data in 1995 and 1997 by adopting the calibration results. We will confirm the rejection power by doing the proton beam tests and develop the analysis method to get higher rejection power against the protons.