IniFial trapping process of ultra slow antiprotons

超慢反质子的初始捕获过程

基本信息

批准号：
07044067
负责人：
YAMAZAKI Yasunori
金额：
$ 1.15万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1995
资助国家：
日本
起止时间：
1995 至无数据
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07044067/
关键词：
antiproton exotic atom capture process Renning trap

项目摘要

The present research project were primarily planned for two years combined with Grant-in-Aid for Scientific Research to construct a transport beamline for ultra slow antiprotons. However, the project was approved only for the first year, which makes it very difficult to keep the consistency over the whole project.The purpose of the project has been to prepare a transport beamline for ultra slow antiprotons extracted from a Penning trap which is installed at LEAR (low energy antiproton ring) of CERN,which enables, for the first time, to investigate the initial trapping processes of antiprotons into atomic orbitals under single collision conditions.Because of the limited time, we have, in the first stage, tried to find a way of cooling trapped antiprotons efectively, and then to optimize the extraction condition of slow antiprotons from the trap. In measuring the annihilation rate of antiprotons in the trap, one can estimate the capture cross section of antiprotons into atomic orbitals of the residual gas, which has been believed to be inversely proportional to the velocity of antiprotons, i.e., the annihilation rate stays constant. However, our experiment shows that the rate increases at the beginning of the cooling, and then start to decrease, which is a clear indication that the capture cross section saturates in the low velocity region or even decreases when the velocity decreases. The present project proceeds satisfactorily without any serious problem except for some delay originating in accelerator troubles. Now we believe that we are ready to make the major part of the proposed experiment successfully for the coming fiscal year, i.e., the beamtime is allocated almost every day from April to September, the beamline is sent out to CERN,etc. It is noted however, that the proposal asking continuation of the support to visit CERN has been rejected.

目前的研究项目主要计划为期两年，并结合科学研究补助金来建造超慢反质子的传输光束线。然而，该项目仅在第一年获得批准，这使得整个项目很难保持一致性。该项目的目的是为从安装的潘宁阱中提取的超慢反质子准备传输束线。 CERN的LEAR（低能反质子环）首次研究了单次碰撞条件下反质子进入原子轨道的初始捕获过程。由于时间有限，我们在第一阶段尝试了到寻找一种有效冷却被捕获反质子的方法，进而优化慢速反质子从陷阱中的提取条件。在测量陷阱中反质子的湮灭率时，可以估计反质子进入残余气体原子轨道的捕获截面，该截面被认为与反质子的速度成反比，即湮灭率保持恒定。然而，我们的实验表明，速率在冷却开始时增加，然后开始下降，这清楚地表明捕获截面在低速区域饱和，甚至当速度减小时减小。目前的项目进展令人满意，除了加速器故障造成的一些延迟外，没有出现任何严重问题。现在我们相信我们已经准备好在下一个财政年度成功完成拟议实验的主要部分，即从4月到9月几乎每天都分配波束时间，将波束线发送到CERN等。但值得注意的是，要求继续支持访问欧洲核子研究中心的提议已被拒绝。