Development of detectors for antiprotonic atom spectroscopy with pulsed antiproton beam

脉冲反质子束反质子原子光谱探测器的开发

• 批准号: 09554018
• 负责人: HAYANO Ryugo
• 金额: $ 5.18万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09554018/
• 关键词: Antiproton; Antiprotonic Helium Atom; Exotic Atom; Cherenkov counter; Laser spectroscopy; Analog method; Pulsed beam; CERN; 光電子増倍管; 低速反陽子ビーム; CPT対称性; 反陽子減速器(AD)

The purpose of this research is to make detailed plans and to develop suitable detectors for the experiments to be done at the pulsed low-energy antiproton source (CERN AD), which is to start operation in 1999. The results are as follows :1. When antiprotons are stopped in helium media, about 97% annihilate promptly (via multiple pion emission) while the rest 3% form antiprotonic helium atoms and become long lived. In order to measure the delayed annihilation time spectrum in strong pulsed beams, it is required to develop an analog recording method having a large enough dynamic range and good linearity.2. We chose Cherenkov counter as the annihilation detector, whose output is to be measured with a photomultiplier tube (PMT). We developed a new mesh-dynode type PMT with a gate so as to suppress the prompt signal, and studied in detail the gate operation and the output linearity. The output of the PMT is recorded on a digital oscilloscope.3. We simulated the behavior of the Cherenkov detector using the Monte Carlo method, and we also measured the response of a prototype detector at an electron synchrotron. The test experiment results were fed back to the simulation, so as to improve its reliability.4. The Cherekov detector with the newly developed PMT was found to satisfy all the requirements, and will be used in the experiments which start in 1999 at CERN AD.

这项研究的目的是为将于1999年开始运作的脉冲低能反质子源（CERN AD）进行的实验制定详细计划并研制适当的探测器。研究结果如下：1.当反质子停止在氦介质中时，大约97%的反质子迅速湮灭（通过多π介子发射），而其余的3%形成反质子氦原子并变得长寿。为了测量强脉冲束延迟湮没时间谱，需要发展一种动态范围足够大、线性度好的模拟记录方法.我们选用切伦科夫计数器作为湮没探测器，用光电倍增管（PMT）测量其输出。为了抑制瞬发信号，我们研制了一种带门极的网状倍增极型光电倍增管，并详细研究了门极的工作原理和输出线性度。PMT的输出记录在数字示波器上。3.我们使用蒙特卡罗方法模拟了切伦科夫探测器的行为，并且还测量了电子同步加速器原型探测器的响应。将测试实验结果反馈到仿真中，提高了仿真的可靠性. Cherekov探测器与新开发的PMT被发现满足所有的要求，并将用于实验中，在1999年开始在CERN AD。

项目成果

B.Ketzer et al.: "Quenching of metastable states of antiprotonic helium stoms by collisions with H2 molecules" Journal of Chemical Physics. 109. 424-431 (1998)

B.Ketzer 等人：“通过与 H2 分子碰撞来淬灭反质子氦原子的亚稳态”《化学物理学杂志》。

K.Yamashita: "Development of antiproton annihilation detectors and analog recording method (in Japanese)" Master thesis, Jan 1999, University of Tokyo.

K.Yamashita：“反质子湮没探测器的开发和模拟记录方法（日语）”硕士论文，1999年1月，东京大学。

B.Ketzer et al.: "Quencing of metastable states of antiprotonic helium atoms by collisions with H2 molecules" Journal of chemical Physics. 109. 424-431 (1998)

B.Ketzer 等人：“通过与 H2 分子碰撞来淬灭反质子氦原子的亚稳态”《化学物理学杂志》。

B.Ketzer et al.: "Quenching of metastable states of antiprotonic helium atoms by collisions with H2 molecules" Journal of Chemical Physics. 109. 424-431 (1998)

B.Ketzer 等人：“通过与 H2 分子碰撞来淬灭反质子氦原子的亚稳态”《化学物理学杂志》。

M.Hori et al.: "Laser spectroscopy studies of state-dependent collisional quenching of the Lifetimes of metastable antiprotonic helium atoms." Physical Review. A58. 1613-1627 (1998)

M.Hori 等人：“亚稳态反质子氦原子寿命的状态相关碰撞猝灭的激光光谱研究。”