Radiation damage at the aluminum entrance window of the SINQ Target 3

Calculations are underway to determine radiation damage (displacement, helium, and hydrogen production) at the entrance window of the SINQ Target 3 (Mark II Type). Damage production rates were determined in two ways. In Method 1, the displacement, He, and H cross-sections were folded into the proton and neutron fluxes to give the three defect production rates separately for protons and neutrons. In Method 2, MCNPX with a computer model of SINQ was used directly to calculate the three production rates due to the combined effects of protons and neutrons. The production rates at the central tip of the target by Method 1 are 4.1 and 0.47 dpa/yr per mA for protons and neutrons, respectively, giving a total of 4.6 dpa/yr per mA. By Method 2 using several approaches, we obtain a range of production rates from 3.6 to 4.1 dpa/yr per mA. For helium, the production rates are calculated to be about 1000 and a range from 950 to 1580 appmHe/yr per mA, respectively. LAHET calculations indicate that the helium is completely retained in the irradiated aluminum. For hydrogen, the calculations indicate that perhaps only about half of the hydrogen produced is retained. Method 1 gives about 3500 appmH/yr per mA retained and Method 2 gives a range from 3500 to 4400 appmH/yr per mA.