Precise measurements of the total reaction cross sectionfor 3He(3He,2p)4HeHe have been made in the range of center-of-massenergies between 1100 keV and 80 keV. A differentially pumpedgas target modified to operate with a limited quantity of the targetgas was employed to minimize the uncertainties in the primaryenergy and energy straggle. Beam integration inside the targetgas was carried out by a calorimetric device which measures thetotal energy spent in a heat sink rather than the total charge in aFaraday cup. Proton energy spectra have been obtained using acounter telescope consisting of a gas proportional counter and asurface barrier detector and angular distributions of these protonshave been measured at seven bombarding energies. Cross sectionfactors, S(E), have been calculated from the total cross sectionsand fitted to a linear function of energy over different ranges ofenergy. For Ecm < 500 keV
S(Ecm) = S0 + S1 Ecm
where S0 = (5.0 +0.6-0.4) MeV - barns and S1 = (-1.8 ± 0.5) barns.
