title: New measurements of W-values for protons and alpha particles.
abstract: The increasing importance of ion beams in cancer therapy and the lack of experimental data for W-values for protons and heavy ions in air require new measurements. A new experimental set-up was developed at PTB and consistent measurements of W-values in argon, nitrogen and air for protons and alpha particles with energies from 0.7 to 3.5 MeV u(-1) at PTB, and for carbon ions between 3.6 and 7.0 MeV u(-1) at GSI were carried out. This publication concentrates on the measurements with protons and alpha particles at PTB. The experimental methods and the determination of corrections for recombination effects, beam-induced background radiation and additional effects are presented.
authors.affiliation: Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, Braunschweig 38116, Germany ulrich.giesen@ptb.de.
authors.forename: U
authors.initials: U
authors.lastname: Giesen
authors.affiliation: Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, Braunschweig 38116, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Beck
mesh_terms: D000388:Air; D000512:Alpha Particles; D001128:Argon; D001417:Background Radiation; D004583:Electrons; D004867:Equipment Design; D005740:Gases; D063193:Heavy Ion Radiotherapy; D006801:Humans; D007477:Ions; D009369:Neoplasms / Q000532:radiotherapy*; D009584:Nitrogen; D011522:Protons; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods*; D011879:Radiotherapy Dosage
chemical_list: D005740:Gases; D007477:Ions; D011522:Protons; D001128:Argon; D009584:Nitrogen