title: The thermal defect of A-150 plastic and graphite for low-energy protons.
abstract: The thermal defects of A-150 plastic and graphite referenced to aluminium were determined for 800 keV protons scattered by a 2 micron nickel foil (mean transmitted energy = 550 keV). Composite cores of Al/A-150, graphite/A-150 and Al/graphite which could be irradiated from one side or the other were employed. The temperature increase of a core caused by 30-100 s of irradiation (3-6 nA of proton beam current) was detected by two thermistors mounted in opposite legs of a Wheatstone bridge. The thermal defect of A-150 plastic was determined to be 0.0421 +/- 0.0036 (SE) referenced to aluminium and 0.0402 +/- 0.0034 referenced to graphite. The thermal defect of graphite referenced to aluminium is 0.0043 +/- 0.0034. No change in the thermal defect of A-150 plastic was detected for accumulated doses up to 8 x 10(5) Gy.
authors.affiliation: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: R J
authors.initials: RJ
authors.lastname: Schulz
authors.forename: N
authors.initials: N
authors.lastname: Venkataramanan
authors.forename: M S
authors.initials: MS
authors.lastname: Huq
mesh_terms: D000535:Aluminum; D055592:Biophysical Phenomena; D001703:Biophysics; D002151:Calorimetry / Q000295:instrumentation*; D006108:Graphite; D006358:Hot Temperature; D006801:Humans; D010969:Plastics; D011522:Protons; D012542:Scattering, Radiation; D013679:Technology, Radiologic
chemical_list: D010969:Plastics; D011522:Protons; C036927:A 150 (plastic); D006108:Graphite; D000535:Aluminum