SUNLAB—The Project of a Polish Underground Laboratory

Natural background radiation at Lab 2 of Callio Lab, Pyhäsalmi mine in Finland

“…The integral count rate on the spectrum up to 2700 keV equals to 654 ± 26 s -1 at the location of neutron flux investigation (MP1), whereas in MP2 and MP3 the values of 673 ± 26 s -1 and 517 ± 23 s -1 , respectively, were found. In other underground locations investigated previously it varies from 1.85 ± 0.02 s -1 in deep salt-rock location [22] through 107.86 ± 0.04 s -1 in deep calcschist-rock formation [23] to 371.50 ± 0.05 s -1 in shallow gneiss formation [18]. The photon flux density, assessed on the base of full-energy peaks, in MP 1 is 12.7 ± 1.5 cm -2 s -1 , and the total spectrum continuum (the total spectrum without full-energy peaks), which contains the contribution of the photons scattered inside the detector and the electromagnetic avalanche from the cosmic rays and their secondaries, is equal to 110.1 ± 12.4 cm -2 s -1 .…”

“…Jinping in marble rock shows 23.22 nSv/h [46], Slanic Prahova, Romania in salt rock reported up to 2.56 ± 0.55 nSv/h [47], salt cavern in Sieroszowice, Poland -2.1 nSv/h [22], and Asse salt mine, Germany 1.3 nSv/h [48]. The result of 0.158 ± 0.029 µSv/h obtained on the base of the gamma-ray spectrum registered in MP 1 in Callio Lab is within the range reported by UNSCEAR for the ground locations in Finland.…”

“…2. Energy calibration (covering the range of 14 -2506 keV) was performed using a set of sealed radioactive sources (1 cm in diameter and about 10 kBq activity): 133 Ba, 137 Cs, 54 Mn, 57 Co, 109 Cd, 22 Na and 60 Co. Identification of in-situ registered radioisotopes was based on the photopeaks' energies.…”

“…As in the previous paper describing radiation environment at TU Bergakademie in Freiberg [18] the ratio of count rates under the peaks of 1460.8 keV and 1764.5 keV from 40 [25]; at Gran Sasso LNGS laboratory in dolomitic limestone covered by concrete it is 2 -6.2 depending on the season [31]; at LSC in Canfranc laboratory in calize rock, which is a calcium carbonate with traces of quartz, it is 5 [32]; in salt rock surrounded by anhydrite layer it is around 3.3 [22]. From this short overview, it seems that the combination of volcanic rock and shotcrete wall coverage is responsible for 40 K/ 214 Bi > 8 for depths greater than 1 km w.e.…”

Characteristics of the natural radioactivity of the underground laboratories in the Baltic Sea Region participating in the BSUIN and EUL projects

“…Due to the long-term operation of the mine, the mine's infrastructure is highly developed. It includes several large access shafts (up to 7.5 m in diameter), an extensive network of underground roads, a ventilation system, machines for fully mechanized mining, and underground transport vehicles (Zalewska, et al, 2010;Kisiel et al, 2010a). At KGHM Polska Miedź S.A. there are no typical underground laboratories, but the company has hundreds of kilometers of existing excavation pits easily accessible and passable.…”