The Advanced Hydrotest Facility (AHF) at Los Alamos will provide proton radiography of large-scale, dynamic events. The large bore (Case II) quadrupole focusing magnets are a subsystem in. this facility, consisting of four complete imaging lines with a total of eight imaging plates and 52 quadrupole magnets. Each large bore quadrupole has an inner winding diameter of 660 mm and provides a gradient of 10.4 T/m with a 300 mm field of view. Each magnet is a two-layer saddle, contained by a three cm steel shell. The conductor is a Rutherford cable, soldered into a C-shaped copper channel. The magnets are. cooled by the forced-flow of two-phase helium through coolant pipes. Since the winding was calculated to absorb bursts of 0.35 J/kg irradiation, both NbTi and Nb-3 Sn designs are being considered.

We present the first AMS measurement of the 81Kr concentration in atmospheric krypton. The measurement was performed by combining positive-ion production in an electron cyclotron resonance source with acceleration to high energy in a cyclotron and subsequent full stripping for 81Br81Kr separation. The result, 81KrKr = (5.3 ± 1.2) × 10−13, agrees well with two previous low-level decay counting measurements.