Cherenkov Detector for K/π Identification and γ-ray Detection in the Rare Decay K^+→π^+vv

切伦科夫探测器用于稀有衰变中的 K/π 识别和 γ 射线检测 K^+→π^+vv

• 批准号: 12640299
• 负责人: KOBAYASHI Masaaki
• 金额: $ 1.47万
• 依托单位: KEK, High Energy Accelerator Research Organization
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640299/
• 关键词: Cherenkov Detector; K; π Identification; K+Rare Decay Experiment; Lead Tungstate PbWO_4; Silicon Strip Detector; Charge Preamplifier; ガンマ線検出器; アクチヴ デグレーダー

We have developed a new heavy, fast-response, and radiation-hard Cherenkov radiators based on lead tungstate (PbWO4, PWO) by heavy doping with rare-earth 3+ ions (GD3+, La3+)by a concentration of 3-8 mol%. We have confirmed the performance with the 500-1000 MeV/c π+ and proton beam at KEK-PS. The radiation hardness was measured for 60Co γ-rays at JAERI (Takasaki) for the accumulated dose of 1k-100k gray (1grey = 100rad).We have also studied the effects of many other dopants in PWO and found that Th4+ ions by 〜100 mol ppm gives dramatical improvement to PWO similar to 3+ ions. A few dopants increase the light yield significantly for PET diagnosis with a time gate of a few hundred ns.Another method to efficiently discriminate between K+ and π+ is to measure dE/dx precisely. We have carried out an R＆D of fast-readout and medium-segmented Si-strip detector (92x92 mm2) and readout pitch of 0.82 mm. This Si detector can withstand high intensity charged particles at a rate of 〜10MHz. The equivalent noise charge (ENC) well less than 3000e is promising for the K+ rare decay experiment (E949) at AG

我们以钨酸铅（PbWO4、PWO）为基础，通过重掺杂稀土3+离子（GD3+、La3+），浓度为3-8 mol%，开发出一种新型重质、快速响应、抗辐射切伦科夫辐射器。我们已经在 KEK-PS 上确认了 500-1000 MeV/c π+ 和质子束的性能。在 JAERI（高崎）测量了 60Co γ 射线的辐射硬度，累积剂量为 1k-100k 格雷（1grey = 100rad）。我们还研究了 PWO 中许多其他掺杂剂的影响，发现〜100 mol ppm 的 Th4+ 离子与 3+ 离子类似，对 PWO 具有显着的改善。一些掺杂剂可以显着提高 PET 诊断的光输出，时间门为几百纳秒。有效区分 K+ 和 π+ 的另一种方法是精确测量 dE/dx。我们研发了快速读出、中分段硅带探测器（92x92 mm2），读出间距为0.82 mm。该硅探测器可以承受〜10MHz速率的高强度带电粒子。远低于 3000e 的等效噪声电荷 (ENC) 对于 AG 的 K+ 稀有衰变实验 (E949) 很有希望

项目成果

M.Fujita et al.: "Optical anisotropy of exciton effect in sheelite PbWO_4 crystals"J.Phys.Soc.Japan. 70. 1439-1440 (2001)

M.Fujita 等：“白钨矿 PbWO_4 晶体中激子效应的光学各向异性”J.Phys.Soc.Japan。

M.Kobayashi et al.: "Silicon strip detector as a real-time, fast and medium-segmented hodoscope"Nucl. Instr. Meth.. (to be published). (2002)

M.Kobayashi 等人：“硅条检测器作为实时、快速和中分段的视距仪”Nucl。

M.Fujita et al.: "Optical anisotropy of exciton band and doping effect in sheelite PbWO_4 crystals"J. Phys. Soc. Japan. 70. 1439-1440 (2001)

M.Fujita等：“白钨矿PbWO_4晶体中激子带的光学各向异性和掺杂效应”J。

M.Chiba et al.: "Antiproton-nucleon annihilation into π^oM and ηM with M=η, ω, ρ and π in antiproton-deuterium annihilation at rest"J.Phys.Soc Japan. 69. 1356-1365 (2000)

M.Chiba 等人：“静止状态下的反质子-氘湮灭中的反质子-核子湮灭为 π^oM 和 ηM，其中 M=η、ω、ρ 和 π”J.Phys.Soc Japan. 69. 1356-1365 (2000) ）

S.Adler et al.: "Measurement of direct photon emission in K^+→π^+π^0γ decay"Phys.Rev.Lett.. 85. 4856-4859 (2000)

S.Adler 等人：“K^+→π^+π^0γ 衰变中直接光子发射的测量”Phys.Rev.Lett.. 85. 4856-4859 (2000)