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A technique for producing deuterated polyethylene targets
NUCLEAR
INSTRUMENTS
AND
METHODS
40 (I966) 359; © N O R T H - H O L L A N D
PUBLISHING
CO.
A TECHNIQUE FOR PRODUCING DEUTERATED POLYETHYLENE TARGETS G. T. J ARNISON
Umted Kingdom Atomtc Energy Authority, A WRE, Aldermaston, Berks. England Recewed 18 December 1965
Deuterated polyethylene (CD2), is a convenient deuterium target for some nuclear physics experiments. Targets thicker than about 20 mg/cm 2 can be made by mechanical methods and thinner ones by vacuum evaporation1). This note describes an alternative method, which is not so wasteful as the evaporation method, for making deuterated polyethylene targets in the thickness range 1 to 20 mg/cm 2. The targets are made by weighing the required amount of CD 2 and dissolving it in a small quantity of warmed xylene. A shallow stainless steel tray is polished, cleaned and sodium chloride evaporated onto its surface to a thickness of 100/~g/cm z to act as a stripping agent. The tray is then heated to 200°C on a hot plate and the xylene solution poured into it and allowed to
359
cool at a rate of about 10°C/min. The tray is immersed in a dish of warm water and the film slowly stripped off, the edges of the tray being scored to facilitate this operation. The film is dried between tissues. The tray must be exactly horizontal on the hot plate otherwise the resultant film is non-uniform. The temperature of the tray must not be too h~gh, otherwise the film blisters and is uneven, conversely if the temperature is too low the C O 2 is not fused into a homogeneous film. The material efficiency of the method is 95%. Reference 1) M. White, Vacuum evaporation of polythene, Vacuum 15, 9,
449.
INSTRUMENTS
AND
METHODS
40 (I966) 359; © N O R T H - H O L L A N D
PUBLISHING
CO.
A TECHNIQUE FOR PRODUCING DEUTERATED POLYETHYLENE TARGETS G. T. J ARNISON
Umted Kingdom Atomtc Energy Authority, A WRE, Aldermaston, Berks. England Recewed 18 December 1965
Deuterated polyethylene (CD2), is a convenient deuterium target for some nuclear physics experiments. Targets thicker than about 20 mg/cm 2 can be made by mechanical methods and thinner ones by vacuum evaporation1). This note describes an alternative method, which is not so wasteful as the evaporation method, for making deuterated polyethylene targets in the thickness range 1 to 20 mg/cm 2. The targets are made by weighing the required amount of CD 2 and dissolving it in a small quantity of warmed xylene. A shallow stainless steel tray is polished, cleaned and sodium chloride evaporated onto its surface to a thickness of 100/~g/cm z to act as a stripping agent. The tray is then heated to 200°C on a hot plate and the xylene solution poured into it and allowed to
359
cool at a rate of about 10°C/min. The tray is immersed in a dish of warm water and the film slowly stripped off, the edges of the tray being scored to facilitate this operation. The film is dried between tissues. The tray must be exactly horizontal on the hot plate otherwise the resultant film is non-uniform. The temperature of the tray must not be too h~gh, otherwise the film blisters and is uneven, conversely if the temperature is too low the C O 2 is not fused into a homogeneous film. The material efficiency of the method is 95%. Reference 1) M. White, Vacuum evaporation of polythene, Vacuum 15, 9,
449.