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Abstract

Measurements of total proton reaction cross sections by the beam-attenuation method involve determinations of the number of protons removed from the incident beam by an absorber compared to those transmitted. This work presents an adaptation of the associated particle technique to enable total reaction cross section measurements for the 15.8 MeV protons from the ³He(d,p)⁴He reaction. A thick heavy ice target is bombarded with 600-keV³ He particles. The ⁴He particles are detected in a silicon surface-barrier detector, and the protons, after traversing the absorber, in a CsI scintillation counter. Both the spatial collimation and the time of arrival of the proton are defined by the detection of the associated ⁴He particle. Thus, removal of a proton from the proton "beam" is identified by an anticoincidence between the ⁴He and proton counters, whereas proton transmission is identified by a coincidence. The limitations and applications of the technique are presented, as well as a discussion of the critical portions of the experimental design.