Charged Particle Spectroscopy on Omega (Final report)

Using the 2-MeV Van de Graaf Accelerator at SUNY Geneseo's Nuclear Structure Laboratory, a 3He-implanted tantalum target was bombarded by 450-keV deuterons to produce high energy protons via the 3He(d,p)4He reaction. A 1500-micro m surface barrier detector with a 3/16 inch diameter collimator was placed at 8.75 cm from the target and 135o from the incident beam. A movable arm was setup so that an array of aluminum filters of varying thicknesses could be rotated in front of the detector. A 6-micro m mylar filter was also mounted on the movable arm and was used to calibrate the detector as described in the CR-39 experiment report. Eight aluminum filters with thicknesses ranging from 250pm to 1100micro m were in turn rotated in front of the collimator and spectra were taken for each. The results are shown on the attached graphs. The theoretical curve for each graph was generated using TRIM The exact energy distribution of the proton beam incident on the target was not known; because no such spectrum could be taken due to the high count rate for elastically scattered deuterons. Instead, it was assumed that the incident beam had a distribution similar to that measured through the 6-micro m mylar, namely, an average energy of 13.798 MeV with a standard deviation of 0.027 MeV. A program developed locally was used to generate an input file for TRIM with this distribution. Using this input file, TRIM simulations were run for various thicknesses of Aluminum, from 200 to 1100 micro m in 50-micro m increments. The solid line on the graph indicates the energies of the transmitted protons. The two dashed lines indicate one standard deviation above and below the average exit energy. TRIM agrees well with the experimental results