The analysis of interface emulsion detector for the OPERA experiment in JAPAN scanning facility.
The analysis of interface emulsion detector for the OPERA experiment in JAPAN scanning facility.
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日本扫描设备OPERA实验界面乳液检测器分析。
DOI：
10.1088/1748-0221/5/04/p04009
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
T. Fukuda et.al .
中科院分区：
文献类型：
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作者：
T.Shimoda;他;永井雄也;石渡 聡;松本浩典;Hiroshige Shiga;山崎高幸;T. Fukuda et.al .
OPERA实验旨在寻找中微子振荡，于2008年7月开始进行物理运行。这是最新的乳胶计数器混合实验。在这个实验中，使用了两种不同类型的乳胶检测器。一种称为乳胶云室（ECC），用作靶。另一种称为可变片（CS），它附着在每个ECC的下游侧，以识别发生标记中微子相互作用的ECC。CS接口中获得的电子探测器的ECC的粗略跟踪信息，因此是一个关键要素的仿真计数器混合实验。作为第一步，扫描和分析由电子检测器选择的CS，以决定是否要详细开发和分析ECC;由于电子检测器的不准确性，通常要分析几个CS，以识别每个标记事件的ECC。CS具有较大的扫描区域，因此日本和欧洲（Gran Sasso）分担CS分析负载以处理扫描工作。在本文中，CS分析方法开发的日本扫描设备进行了详细说明。利用乳胶自动读出系统（S-UTS）在每个CS上读出了1亿条径迹，其中大部分是由低动量康普顿电子或随机噪声引起的所谓假径迹，少数来自标记中微子相互作用的真实的径迹需要在巨大的背景中拾取。一种专门的方法，以拒绝这种背景，而不丢失真实的轨道已开发的基础上，分析由S-UTS获得的轨道数据，并结合这些数据与最终的选择，使用额外的信息，通过人眼检查获得的候选轨道的多库仑散射，以消除剩余的背景。这种方法的性能被证明是足够的OPERA实验。
The OPERA experiment, designed to search for neutrino oscillations, started its physics run in July 2008. It is the most recent emulsion-counter hybrid experiment. In this experiment two different types of emulsion detectors are used. One is called Emulsion Cloud Chamber (ECC), and is used as a target. The other is called Changeable Sheet (CS), which is attached to the downstream side of each ECC to identify the ECC in which a tagged neutrino interaction occurred. The CS interfaces rough tracking information obtained in the electronic detectors to the ECC and therefore is a key element of the emulsion-counter hybrid experiment. As a first step, a CS selected by electronic detectors is scanned and analyzed to decide if the ECC is to be developed and analyzed in detail; a few CS are usually to be analyzed to identify an ECC for each tagged event due to the inaccuracy of the electronic detectors. The CS has a large scanning area and therefore Japan and Europe (Gran Sasso) are sharing in the CS analysis load to handle the scanning job. In this paper, the CS analysis method developed for the Japan scanning facility is described in detail. 100 million tracks are read out on each CS by an automatic emulsion read-out system (S-UTS), most of them are so-called fake tracks mainly due to low momentum Compton electrons or random noise and a few real tracks from a tagged neutrino interaction have to be picked up among a huge background. A dedicated method to reject this background without losing real tracks has been developed on the basis of analyzing track data obtained by S-UTS and combining these data with a final selection using additional information on multiple Coulomb scattering of candidate tracks obtained by human eye check to eliminate a remaining background. Performance of this method is shown to be sufficient for the OPERA experiment.