Cosmic-ray depth studies at the homestate mine with /sup 39/K. -->. /sup 37/Ar detectors

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/sup -1/ per ton of K, which is to be compared to the value of 0.46 +- 0.04 /sup 37/Ar day/sup -1/ per 615 tons of C/sub 2/Cl/sub 4/ in the solar neutrino detector. The 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.