Edinburgh Research Explorer Measurement of the Gamma Ray Background in the Davis Cavern at the Sanford Underground Research Facility
Edinburgh Research Explorer Measurement of the Gamma Ray Background in the Davis Cavern at the Sanford Underground Research Facility
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爱丁堡研究探索者测量桑福德地下研究设施戴维斯洞穴中的伽马射线背景
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通讯作者：
S. Middeldorp
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作者：
S. Kuipers;A. Schreijer;S. Cannegieter;H. Büller;F. Rosendaal;S. Middeldorp
由于宇宙射线通过地球时会衰减，深地下环境是低背景搜索的理想场所。然而，它们受到40 K γ射线和围岩中238 U、232 Th衰变链的背景干扰。LUX-ZEPLIN（LZ）实验将寻找暗物质粒子与位于南达科他州铅市桑福德地下研究设施戴维斯校区内4,850英尺高度的液态氙TPC的相互作用。为了消除洞穴背景，在不同位置用碘化钠探测器和铅屏蔽进行了现场γ射线测量。积分计数率（0-3300千电子伏）变化从596赫兹到1355赫兹的无屏蔽测量，对应于总的1000倍的洞穴。9 ± 0。4 γ cm − 2 s − 1。洞穴壁的放射性活度为220 ± 60 Bq/kg的40 K、29 ± 15 Bq/kg的238 U和13 ± 3 Bq/kg的232 Th。
Deep underground environments are ideal for low background searches due to the attenuation of cosmic rays by passage through the earth. However, they are affected by backgrounds from γ -rays emitted by 40 K and the 238 U and 232 Th decay chains in the surrounding rock. The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a liquid xenon TPC located within the Davis campus at the Sanford Underground Research Facility, Lead, South Dakota, at the 4,850-foot level. In order to characterise the cavern background, in-situ γ -ray measurements were taken with a sodium iodide detector in various locations and with lead shielding. The integral count rates (0–3300 keV) varied from 596 Hz to 1355 Hz for unshielded measurements, corresponding to a total flux in the cavern of 1 . 9 ± 0 . 4 γ cm − 2 s − 1 . The resulting activity in the walls of the cavern can be characterised as 220 ± 60 Bq/kg of 40 K, 29 ± 15 Bq/kg of 238 U, and 13 ± 3 Bq/kg of 232 Th.