Thin pad detectors made from 75 $μ$m thick epitaxial silicon on low resistivity substrate were irradiated with reactor neutrons to fluences from 2.5$\times 10^{16}$ n/cm$^2$ to 1$\times 10^{17}$ n/cm$^2$. Edge-TCT measurements showed that the active detector thickness is limited to the epitaxial layer and does not extend into the low resistivity substrate even after the highest fluence. Detector current was measured under reverse and forward bias. The forward current was higher than the reverse at the same voltage but the difference gets smaller with increasing fluence. Rapid increase of current (breakdown) above ~ 700 V under reverse bias was observed. An annealing study at 60$^\circ$C was made to 1200 minutes of accumulated annealing time. It showed that the reverse current anneals with similar time constants as measured at lower fluences. A small increase of forward current due to annealing was seen. Collected charge was measured with electrons from $^{90}$Sr source in forward and reverse bias configurations. Under reverse bias the collected charge increased linearly with bias voltage up to 6000 electrons at 2.5$\times 10^{16}$ n/cm$^2$ and 3000 electrons at 1$\times 10^{17}$ n/cm$^2$. Rapid increase of noise was measured above $\sim$ 700 V reverse bias due to breakdown resulting in worse S/N ratio. At low bias voltages slightly more charge is measured under forward bias compared to reverse. However better S/N is achieved under reverse bias. Effective trapping times were estimated from charge collection measurements under forward bias showing that at high fluences they are much longer than values extrapolated from low fluence measurements - at 1$\times 10^{17}$ n/cm$^2$ a factor of 6 larger value was measured.
Study of the readout chip and silicon sensor degradation for the CMS pixel upgrade
混合硅像素探测器目前用于紧凑型μ子螺线管(CMS)实验的最内部跟踪系统。已经证明了大型强子对撞机(LHC)运行几年所能承受的辐射通量,尽管预计硅探测器靠近相互作用点的部分会出现一些退化。在大型强子对撞机升级阶段,硅像素探测器预计的剂量水平将高得多。为了面对这个方面,已经在硅传感器和读出芯片上执行了具有高于$\mathcal{O}(10^{15})$ n $_{\textrm{eq}}$ /cm $^2$的注量的专用辐照测试。在操作中的传感器和读出芯片的能量密度的函数的变化。的电荷收集效率进行了研究:部分恢复的检测器的效率,可以通过操作的检测器在一个受控的环境中,并在较高的偏置电压。
Influence of radiation damage on the absorption of near-infrared light in silicon
测量了波长在0 ~ $~$ cm $~μ$之间的光在硅中的吸收长度$~$。结果表明,由于辐照引起的缺陷,$λ_{abs}$随注量的增加而减小。本文给出了室温下$λ_{abs}$的辐射感生变化随波长和中子当量注量的唯象参数。$λ_{abs}$随辐照减少的观察结果通过对辐照硅条探测器的边缘TCT测量得到证实。利用测得的$λ_{abs}$的波长依赖性,确定了硅带隙随注量的变化。
Signal and noise of Diamond Pixel Detectors at High Radiation Fluences
CVD金刚石由于其大的带隙和强的晶格结构而具有很强的抗辐射性,是LHC顶点探测器的一种有吸引力的材料选择。特别地,在相互作用点附近操作的像素检测器受益于金刚石的微小漏电流和小像素电容,从而与硅相比具有低噪声系数。另一方面,来自穿越高能粒子的电荷信号在金刚石中比在硅中小约2.2倍。因此,在超过10 $^{15}$ n $_{eq}$ cm $^{-2}$的注量下,与硅相比,定量测定金刚石的信噪比(S/N)是重要的,这是LHC升级所期望的。基于对辐照金刚石传感器的测量和FE-I4像素读出芯片的设计,我们确定了高粒子注量辐照金刚石像素探测器的信号和噪声。为了表征辐射损伤对材料和信号降低的影响,将载流子的平均自由程$λ_{e/h}$的变化确定为辐射通量的函数。我们利用为ATLAS升级开发的FE-I4像素芯片来实际估计预期的噪声系数:给定通量下的预期漏电流来自校准计算,像素电容使用专门开发的芯片(PixCap)测量。我们比较所得的S/N数字与平面硅像素探测器使用公布的电荷损失测量和相同的外推方法,为金刚石。它示出,预期的S/N的金刚石像素探测器与像素间距典型的LHC,超过平面硅像素在超过10 $^{15}$粒子cm $^{-2}$的注量,确切的值仅取决于最大的操作电压假设为辐照硅像素探测器。
Temperature dependence of the long-term annealing behavior of neutron irradiated diodes from 8-inch p-type silicon wafers
CERN(欧洲核子研究组织);Karlsruhe Institute of Technology(卡尔斯鲁厄理工学院);Heidelberg University(海德堡大学);Uppsala University(乌普萨拉大学);Al-Farabi Kazakh National University(阿尔法拉比哈萨克国立大学);An Najah National University(安纳贾赫国立大学);HAN University of Applied Sciences(汉应用科学大学)
Optimization of various isolation techniques to develop low noise, radiation hard double-sided silicon strip detectors for the CBM Silicon Tracking System
本文报道了双面硅微条探测器(DSSD)的设计优化,以减少等效噪声电荷(ENC),并最大限度地提高击穿电压和电荷收集效率。各种隔离技术进行了探讨,并进行了详细的比较研究,以优化检测器的性能。为了评价硅探测器的性能,已包括辐射损伤模型。在五年的预期CBM运行期间,预计中子注量为每年2 × 10 ^{13} n_{eq} cm $^{-2}$,中间阶段为热维护、冷维护和停堆。已经进行了瞬态模拟,以估计辐照探测器的电荷收集性能和模拟已与实验数据进行了验证。
In-situ Radiation Damage Study of Silicon Carbide Detectors Subjected to Clinical Proton Beams
Marietta Blau Institute for Particle Physics, Austrian Academy of Sciences(玛丽塔·布劳粒子物理研究所,奥地利科学院);Institute of Atomic and Subatomic Physics, TU Wien(维也纳工业大学原子与亚原子物理研究所)
Radiation Tolerance Characterisation of an Indigenously Developed p-type Silicon Pad Sensor for Forward Calorimetry Applications
Variable Energy Cyclotron Centre(变能回旋加速器中心);Homi Bhabha National Institute(霍米·巴巴国立研究所);Jadavpur University(贾达普大学);Bhabha Atomic Research Centre(巴哈原子研究中心);Institute for Plasma Research(等离子体研究所)
Simulation of radiation damage effect on silicon detectors using RASER
Shandong Institute of Advanced Technology(山东高等技术研究院);Jilin University(吉林大学);University of Chinese Academy of Sciences(中国科学院大学);Institute of High Energy Physics, Chinese Academy of Science(中国科学院高能物理研究所);Tsinghua University(清华大学)
Testbeam studies of pre-prototype silicon strip sensors for the LHCb UT upgrade project
LHCb实验正准备在2018-2019年进行重大升级。升级的关键组件之一是位于实验分析磁体上游的新硅跟踪器。上游跟踪器(UT)将由硅条探测器的四个平面组成,每个平面覆盖约2 m $^2$的面积。这些探测器的一个重要考虑因素是它们在暴露于大辐射剂量后的性能。在这篇文章中,我们提出了预原型的n-in-p和p-in-n传感器,已被照射的能量密度高达$4.0\times10^{14}$ $n_{\rm eq}$ cm $^{-2}$的测试束结果。
Radiation Damage Studies of Silicon Photomultipliers
我们报告的硅光电倍增器(SiPM)的辐射硬度的测量由布鲁诺凯斯勒基金会在意大利(1 mm $^2$和6.2 mm $^2$),透视技术和仪器中心在俄罗斯(1 mm $^2$和4.4 mm $^2$),日本滨松公司(1 mm $^2$)。在Massachusetts General Hospital使用212 MeV质子束照射SiPM,SiPM在工作电压下接收高达$3 \times 10^{10}$质子/cm $^2$的注量。在照射期间连续读取漏电流。周期性地暂停质子的递送以记录响应于校准光脉冲的示波器迹线,以监测SiPM的增益、光子检测效率和暗计数。漏电流和暗噪声随注量的增加而增加。Te漏电流被发现是成比例的噪声分布的均方差,表明暗计数是由于增加随机个别像素激活,而SiPM仍然完全功能的光子探测器。发现SiPM在室温下退火,在大约100天内漏电流减少了2倍。
Inter-pad dead regions of irradiated FBK Low Gain Avalanche Detectors
低增益雪崩探测器(LGAD)是一种具有高掺杂增益层的薄硅探测器。由Fondazione Bruno Kessler(FBK)制造的LGAD在中子辐照前后进行了测试。在本研究中,使用TCT激光系统测量焊盘间距离(IPD),定义为焊盘之间距离的宽度。使用来自90 Sr源的$β$粒子调谐激光器的响应。这些不敏感的“死区”是由保护结构产生的,以避免击穿,连接端接扩展(JTE),它将焊盘分开。研究了\fluence{1.5}{15}和\fluence{2.5}{15}的中子辐射损伤对IPD的影响。将这些距离与供应商给出的标称距离进行比较,发现更高的通量对应于标称IPD的更好匹配。