Em the Sljc Lh2 Target Control System*

Liquid Hydrogen (LH2) is utilized as a target for the high energy electron beams, up to 20 GeV, available from the two-mile Stanford Linear Accelerator because hydrogen is the purest form of protons attainable and liquefaction increases the density of the protons available for bombardment. This paper will deal with the necessary control systems required for the LH2 target, and special systems desired by experimenters. Figure 1 is a sketch of the system. Components are situated at three or four locations. The target assembly itself is located directly in the beam line and is usually in an inaccessible high radiation area. The IX2 supply is located outside the high radiation area as close to the target as possible and the controls are in an accessible location, near the experi-menter's equipment. The only component of the system of any interest to the experimenter is the LH2 cell-target of the electron beam. Ideally the experimenter would like a mass of LH2 suspended in a vacuum with a zero mass container. Since this is not yet available, they have accepted-such materials as mylar (between 5 to 15 mils thick depending upon the size and shape of target), aluminum No. 6061 T-6 (3 to 6 mils), and stainless steel No. 314 (1 to 3 mils). The experimenter might be interested in any of the following. parameters of this cell: