We successfully revealed the adsorption behavior of actual organic contaminations on a Si wafer surface using a gas chromatograph/mass spectrometer system with a quartz heat-desorption chamber and a two-step concentration trap. Antioxidants contained in the wafer case material and a monomer and an oligomer from the plastic vessel material used in the production process were confirmed to contaminate the surface of the Si wafer. Organic materials in the atmosphere, such as organic solvents and plasticizers, were also observed to adsorb on the surface during an exposure to a laboratory atmosphere for a few hours. The results suggest that completely surface-cleaned Si wafers should be stored in a stocker in which the amount of organic species in the atmosphere is well controlled.

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Irradiation experiments were performed at the HIMAC (Heavy Ion Medical Accelerator in Chiba) facility, National Institute of Radiological Sciences, Japan. The radioactivity distributions of spallation products in a thick Cu target were obtained by irradiating 230 and 100MeV/nucleon Ne, C, He,

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