Cosmic-Ray Depth Studies at the Homestake Mine with sup 39 K Yields sup 37 Ar Detectors

摘要

The argon-37 production rates in potassium detectors are measured at depths down to 4850 ft (4000 m.w.e.), the location of the chlorine solar neutrino detector in the Homestake Mine. The depth variation of the sup 37 Ar production rates in K agrees with that expected from cosmic ray muon interactions. At shallow depths, the sup 37 Ar production rates in K parallel those in Cl, with the sup 37 Ar rate per ton K equal to the sup 37 Ar rate per 615 tons of C sub 2 Cl sub 4 . At 4850 ft depth, the measurements give 0.07 +- 0.07 sup 37 Ar day exp -1 per ton of K, which is to be compared to the value of 0.46 +- 0.04 sup 37 Ar day exp -1 per 615 tons of C sub 2 Cl sub 4 in the solar neutrino detector. The comparison indicates that there is an excess of sup 37 Ar over the cosmic-ray production in chlorine at 4850 ft depth; however, the error in the K measurements at 4850 ft depth is presently too large to determine accurately the cosmic ray background of the solar neutrino experiment. This error will be reduced by additional measurements. 11 references, 3 tables. (ERA citation 10:010452)