Development of Positron Mass-Production Method

正电子量产方法的开发

• 批准号: 03559004
• 负责人: MOHRI Akihiro
• 金额: $ 8.32万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03559004/
• 关键词: Slow positron; Positron production; LINAC; Pair creation; Converter; Moderator; Magnetic duct as; Solid film of gas atoms; LINAC; 電子ビーム; 磁場ダクト; 貴ガス氷薄膜; 減速材; ライナック応用; 光子一陽電子変換器; 陽電子プラズマ; ambiプラズマ; 再減速器; 対創生; 対消滅; 光子-陽電子変換器; 陽電子移送磁場チャンネ

The research and development on positron mass-production by using a high current LINAC have been performed for three years. The following improvements in Production Efficiency of Low Energy Positrons have been obtained.1. Efficient converter, named "Modular Photon-Positron Converter"(MPPC), form energetic photons to slow positrons were developed. This converter can enlarge the positron emitting surface of tungsten foils which emit slow positrons at bombardment of energetic photons, and also extract them by applying effective electric field. Experiments on the proof of the principle showed that MPPC works well and the production rate is in agreement of the estimation based on Monte-Carlo simulations using EGS4 code.2. Efficient converter, named "Photon-Nonthermal Positron Converter"(PNPC), was developed. Extraction of positrons of low energy region can increase the net positron production efficiency dramatically. It was experimentally proved that the production rate per unit surface area of tungsten foil became 15-20 times that in the case of (1). The attained production rate during the LINAC beam pulse was 2 X 10^<13>[e^+/s] and the time averaged one for 100 pps reached 8 X 10^8[e^+/s], in spite of the used low LINAC beam energy as 30 MeV.This converter is very simple in structure and it can be fablicated easily.3. Other developments in transportation of positrons with a magnetic duct and also in remoderation of them were made. The attained time averaged production rate of positrons below 6 eV was 3.3 X 10^7[e^+/s].

利用大电流直线加速器进行正电子量产的研发已经进行了三年。在低能正电子生产效率方面取得了如下改进： 1．开发了一种高效转换器，称为“模块化光子-正电子转换器”（MPPC），将高能光子形成慢速正电子。该转换器可以扩大钨箔的正电子发射表面，钨箔在高能光子轰击时会发射慢速正电子，并通过施加有效电场将其提取出来。原理证明实验表明MPPC效果良好，生产率与基于EGS4代码的蒙特卡罗模拟的估计结果相符。 2．研制出高效转换器，命名为“光子-非热正电子转换器”（PNPC）。低能区正电子的提取可以显着提高净正电子的生产效率。实验证明，钨箔单位表面积的生产率是(1)的情况的15～20倍。尽管使用的LINAC束流能量为30 MeV，但在LINAC束流脉冲期间获得的生产率为2 X 10^<13>[e^+/s]，并且100 pps的平均时间达到8 X 10^8[e^+/s]。该转换器结构非常简单，易于制造。 3．在利用磁导管传输正电子以及对其进行改造方面也取得了其他进展。低于 6 eV 的正电子所达到的时间平均生产率为 3.3 X 10^7[e^+/s]。

项目成果

H.Tanaka: "Slow Positron Production with a Modular Photon-Positron Converter Attached to a High-Curent LINAC" Jpn.J.Appl.Phys.31-12A. 4029-4036 (1992)

H.Tanaka：“使用连接到高电流直线加速器的模块化光子-正电子转换器来缓慢产生正电子”Jpn.J.Appl.Phys.31-12A。

毛利明博: "固体キセノン薄膜を用いた陽電子の減速" 京都大学原子炉実験所「放射線誘起構造変化(IV)」KURRI-TR-383. 10-14 (1993)

Akihiro Mori：“使用固体氙薄膜减速正电子”京都大学反应堆研究所“辐射引起的结构变化（IV）”KURRI-TR-383（1993）。

A.Mohri: "Production and Stacking of Slow Positron Beams Generated with a High Current Linac" Proc.of 10th Int.Conf.Positron Annihilation, (Beijing, May, 1994) paper : C1-1. (to be published).

A.Mohri：“用高电流直线加速器生成慢速正电子束的产生和堆叠”Proc.of 10th Int.Conf.Positron Annihilation，（北京，1994 年 5 月）论文：C1-1。

Y.Yuyama: "Production of Positrons using LINAC" Prod.27th Sci.Meeting of KURRI. 1-6 (1993)

Y.Yuyama：“使用 LINAC 生产正电子”Prod.27th Sci.Meeting of KURRI。

毛利明博: "Method to Generate a Large Number of Slow Positron Production with a Modular Photon-Positron Converter" Jpn.J.Appl.Phys.30. L936-L939 (1991)

Akihiro Mori：“使用模块化光子-正电子转换器产生大量缓慢正电子的方法”Jpn.J.Appl.Phys.30 (1991)。