AN ASSOCIATED PARTICLE METHOD FOR MEASURING TOTAL PROTON REACTION CROSS SECTIONS AT 15.8 MEV

Measurements of total proton reaction cross sections by the attenuation method involve the determination of the ratio of particles absorbed in the target to those transmitted. The associated particle technique has been adapted to enable total reaction cross section measurements for the 15.8 MeV protons from the 2H(3He,p)4He reaction. Detection of the 4He defines the spatial collimation and time of arrival of the associated proton. Anticoincidence and coincidence measurements between the 4He's and the associated proton after traversal of the absorbing target, are performed. The ratio of these measurements yield values for the attenuation of the proton beam in the target. Measurements were performed for targets of gold and natural copper and iron. The cross sections so obtained were measured to an accuracy of 10%. A number of improvements to decrease the uncertainty to better than 5% are also discussed. © 1968.