The Hall A cryogenic target system
consists of two completely instrumented targets, H
and D. In addition
a third target loop is installed in the scattering chamber
but this target is not usually connected to a full gas handling system.
This third loop is used as a helium target.
The hydrogen and deuterium targets present a number of potential hazards, such as the fire/explosion hazard of the flammable gas as well as the hazards connected with the vacuum vessel and the of handling cryogenic liquids (ODH and high pressure). In this document the hydrogen target will be referred to, but the deuterium target is essentially identical and almost all comments apply to both targets.