The cryogenic target for the experiment at Jefferson lab

Abstract: A cryogenic horizontal single loop target has been designed, built, tested and operated for the experiment in Hall C at Jefferson Lab. The target cell is 20cm long, the loop volume is 6.5l and the target operates with the cryogenic pump fully immersed in the fluid. The target has been designed to operate at 30Hz rotational pump speed with either liquid hydrogen or liquid deuterium. The high-power heat exchanger is able to remove 1000W of heat from the liquid hydrogen, while the nominal electron beam with current of and energy of 3GeV deposits about 320W of heat into the liquid. The increase in the systematic uncertainty due to the liquid hydrogen target is negligible on the scale of a parity violation experiment. The global normalized yield reduction for beam is about 1.5% and the target density fluctuations contribute less than 238ppm (parts per million) to the total asymmetry width, typically about 1200ppm, in a bin. [Copyright &y& Elsevier]