Ionization yield measurement in a germanium CDMSlite detector using photo-neutron sources
SuperCDMS Collaboration, M. F. Albakry, I. Alkhatib, D. W. P. Amaral, T. Aralis, T. Aramaki, I. J. Arnquist, I. Ataee Langroudy, E. Azadbakht, S. Banik, C. Bath… 展开作者
SuperCDMS Collaboration, M. F. Albakry, I. Alkhatib, D. W. P. Amaral, T. Aralis, T. Aramaki, I. J. Arnquist, I. Ataee Langroudy, E. Azadbakht, S. Banik, C. Bathurst, D. A. Bauer, L. V. S. Bezerra, R. Bhattacharyya, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y. -Y. Chang, M. Chaudhuri, R. Chen, N. Chott, J. Cooley, H. Coombes, J. Corbett, P. Cushman, F. De Brienne, M. L. di Vacri, M. D. Diamond, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, K. Fouts, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, J. Hall, B. A. Hines, M. I. Hollister, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, A. Jastram, V. K. S. Kashyap, M. H. Kelsey, A. Kubik, N. A. Kurinsky, R. E. Lawrence, M. Lee, A. Li, J. Liu, Y. Liu, B. Loer, P. Lukens, D. MacDonell, D. B. MacFarlane, R. Mahapatra, V. Mandic, N. Mast, A. J. Mayer, H. Meyer zu Theenhausen, É. Michaud, E. Michielin, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, S. Nagorny, J. Nelson, H. Neog, V. Novati, J. L. Orrell, M. D. Osborne, S. M. Oser, W. A. Page, R. Partridge, D. S. Pedreros, R. Podviianiuk, F. Ponce, S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, T. Saab, B. Sadoulet, I. Saikia, J. Sander, A. Sattari, A. Scarff, B. Schmidt, R. W. Schnee, S. Scorza, B. Serfass, D. J. Sincavage, C. Stanford, J. Street, F. K. Thasrawala, D. Toback, R. Underwood, S. Verma, A. N. Villano, B. von Krosigk, S. L. Watkins, O. Wen, Z. Williams, M. J. Wilson, J. Winchell, K. Wykoff, S. Yellin, B. A. Young, T. C. Yu, B. Zatschler, S. Zatschler, A. Zaytsev, E. Zhang, L. Zheng, S. Zuber
由SuperCDMS合作组研制的两种光中子源$^{88}$ Y $^{9}$ Be和$^{124}$ Sb $^{9}$ Be被用于研究CDMSlite锗探测器中的核反冲电离产额。这项工作评估的产率为1千电子伏和7千电子伏之间的核反冲能量在$\sim$ 50毫K的温度。我们使用Geant4模拟中子谱假设的电荷产额模型，这是一个推广的标准Lindhard模型，由两个能量相关的参数。我们使用模拟的中子能谱、建模的背景和实验数据进行似然分析，以获得产率模型的最佳拟合值。反冲能量为1千电子伏和7千电子伏之间的电离产率被证明是显着低于预测的标准Lindhard模型锗。使用各种技术研究核反冲产额的低能范围的不同实验之间普遍缺乏一致性，这对于解释直接暗物质搜索是最关键的。这表明许多直接检测实验用于模拟其主要信号检测机制的物理过程的复杂性，并强调需要进一步研究以澄清迄今为止尚未很好理解的潜在系统效应。
英文摘要：
Two photo-neutron sources, $^{88}$Y$^{9}$Be and $^{124}$Sb$^{9}$Be, have been used to investigate the ionization yield of nuclear recoils in the CDMSlite germanium detectors by the SuperCDMS collaboration. This work evaluates the yield for nuclear recoil energies between 1 keV and 7 keV at a temperature of $\sim$ 50 mK. We use a Geant4 simulation to model the neutron spectrum assuming a charge yield model that is a generalization of the standard Lindhard model and consists of two energy dependent parameters. We perform a likelihood analysis using the simulated neutron spectrum, modeled background, and experimental data to obtain the best fit values of the yield model. The ionization yield between recoil energies of 1 keV and 7 keV is shown to be significantly lower than predicted by the standard Lindhard model for germanium. There is a general lack of agreement among different experiments using a variety of techniques studying the low-energy range of the nuclear recoil yield, which is most critical for interpretation of direct dark matter searches. This suggests complexity in the physical process that many direct detection experiments use to model their primary signal detection mechanism and highlights the need for further studies to clarify underlying systematic effects that have not been well understood up to this point.
