A proton activation diagnostic to measure D-- sup 3 He reaction yields

• Published in: Review of scientific instruments 1992-10, Vol.63:10
• Main Authors: Lierzer, J.R., Wenzel, K.W., Petrasso, R.D., Lo, D.H., Coleman, J.W., Li, C.K., Hsieh, E., Bernat, T.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 700320 - Plasma Diagnostic Techniques & Instrumentation- (1992-); ACTIVATION DETECTORS; ALCATOR DEVICE; BARYON REACTIONS; BARYONS; BETA DECAY RADIOISOTOPES; BETA-PLUS DECAY RADIOISOTOPES; CHARGED PARTICLE DETECTION; CHARGED-PARTICLE REACTIONS; CLOSED PLASMA DEVICES; DAYS LIVING RADIOISOTOPES; DETECTION; DEUTERON REACTIONS; ELECTRON CAPTURE RADIOISOTOPES; ELEMENTARY PARTICLES; FEASIBILITY STUDIES; FERMIONS; FUSION YIELD; HADRON REACTIONS; HADRONS; HELIUM 3 TARGET; INTERMEDIATE MASS NUCLEI; ISOTOPES; MEASURING INSTRUMENTS; NEUTRON DETECTORS; NUCLEAR REACTION YIELD; NUCLEAR REACTIONS; NUCLEI; NUCLEON REACTIONS; NUCLEONS; ODD-ODD NUCLEI; PLASMA DIAGNOSTICS; PROTON DETECTION; PROTON REACTIONS; PROTONS; RADIATION DETECTION; RADIATION DETECTORS; RADIOISOTOPES; TARGETS; THERMONUCLEAR DEVICES; TITANIUM 48 TARGET; TOKAMAK DEVICES; VANADIUM 48; VANADIUM ISOTOPES; YIELDS
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.1143580

We are developing activation diagnostics for monitoring energetic charged-particle fluxes in space and laboratory plasmas. More immediately, we plan to use activation to measure the time-integrated proton flux from D--{sup 3}He fusion reactions in Alcator C-MOD, providing a measure of the time-averaged D--{sup 3}He fusion rate. We demonstrated the technique's feasibility by inducing significant gamma activity in a titanium sample exposed to D--{sup 3}He protons created in our Cockcroft--Walton generator. The titanium target received a fluence of 5.5{times}10{sup 9} protons at 14.7 MeV (of order what a 3-cm{sup 2} target should receive from one shot in Alcator C-MOD) and became activated by the{sup 48}Ti({ital p},{ital n}){sup 48}V reaction. The activity's spectrum from a high-purity germanium (HPGe) detector showed the characteristic 0.984- and 1.312-MeV lines of {sup 48}V. The measured activity agreed reasonably well with theory. An absence of activity at those energies before D--{sup 3}He activation eliminated background or D--D product-induced activity as the gamma source. We intend to repeat the experiment with a chromium target to evaluate that material's diagnostic potential.