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arXiv physics/0412085physics.ins-det
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高能质子对钨酸铅量能器晶体的损伤

High-energy proton induced damage in Lead Tungstate calorimeter crystals

M. Huhtinen, P. Lecomte, D. Luckey, F. Nessi-Tedaldi, F. Pauss

摘要:

用20 GeV/c的质子束辐照了8个CMS生产级PbWO_4晶体,辐照剂量高达5.4E ~(13)cm ~(-2)。这些晶体的损伤恢复已经进行了一年多。使用1 kGy/h的剂量率,对其他7个晶体进行了60 Co光子的比较辐照。在质子辐照的晶体中,光透射带边移动,并且诱导吸收长度与波长的4次方的倒数成正比。在γ射线辐照的晶体中,带边不移动,但吸收带的形成是清楚可见的。晶体中γ辐射引起的吸收长度被证实具有优异的辐射硬度,在低于0.5 m-1的水平饱和。在质子的情况下,我们观察到没有相关性的预表征的辐射硬度的晶体和诱导吸收增加与注量线性。在5E 13 cm-2的能量密度后,诱导吸收长度约为100 nm。15 m-1,没有饱和迹象。这些观察结果提供了强有力的证据,表明高能质子造成的损伤是伽马射线照射无法复制的。然而,这些强子效应只在积分注量远超过1 E12 cm-2时才显现出来,并且很可能在较低注量时逃逸而未被发现。在质子和伽马辐照的晶体中,很大一部分损伤要么是稳定的,要么恢复得非常缓慢。

英文摘要:

Eight production quality PbWO4 crystals of CMS have been irradiated in a 20 GeV/c proton beam up to fluences of 5.4E13cm-2. The damage recovery in these crystals has been followed for over a year. Comparative irradiations with 60Co photons have been performed on seven other crystals using a dose rate of 1 kGy/h. In proton irradiated crystals the light transmission band-edge shifts and the induced absorption length is proportional to the inverse of the 4th power of the wavelength. In gamma-irradiated crystals the band-edge does not shift but formation of absorption bands is seen clearly. The absorption length induced by gamma-radiation in crystals verified to have excellent radiation hardness, saturates at a level below 0.5 m-1. In the case of protons, we observe no correlation with the pre-characterised radiation hardness of the crystals and the induced absorption increases linearly with fluence. After a fluence of 5E13 cm-2, an induced absorption length of approx. 15m-1 is seen with no sign of saturation. These observations provide strong evidence that high-energy protons create damage that cannot be reproduced with gamma-irradiation. However, these hadronic effects manifest themselves only at integral fluences well beyond 1E12cm-2 and most likely would escape undetected at lower fluences. A large fraction of the damage, both in proton- and gamma-irradiated crystals, is either stable or recovers very slowly.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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