Time-of-flight spectrometry of ultra-short, polyenergetic proton bunches.

Autor:	Würl M; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany., Englbrecht FS; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany., Lehrack S; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany., Gianoli C; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany., Lindner FH; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany., Rösch TF; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany., Haffa D; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany., Olivari F; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany., Petasecca M; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia., Lerch MLF; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia., Pogossov A; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia., Tran LT; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia., Assmann W; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany., Schreiber J; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany., Rosenfeld AB; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia., Parodi K; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany.
Jazyk:	angličtina
Zdroj:	The Review of scientific instruments [Rev Sci Instrum] 2018 Dec; Vol. 89 (12), pp. 123302.
DOI:	10.1063/1.5052059
Abstrakt:	A common approach for spectrum determination of polyenergetic proton bunches from laser-ion acceleration experiments is based on the time-of-flight (TOF) method. However, spectra obtained using this method are typically given in relative units or are estimated based on some prior assumptions on the energy distribution of the accelerated ions. In this work, we present a new approach using the TOF method that allows for an absolute energy spectrum reconstruction from a current signal acquired with a sub-nanosecond fast and 10 µ m thin silicon detector. The reconstruction is based on solving a linear least-squares problem, taking into account the response function of the detection system. The general principle of signal generation and spectrum reconstruction by setting up an appropriate system response matrix is presented. Proof-of-principle experiments at a 12 MV Tandem accelerator using different nanosecond-short (quasi-)monoenergetic and polyenergetic proton bunches at energies up to 20 MeV were successfully performed. Within the experimental uncertainties of 2.4% and 12.1% for energy and particle number, respectively, reconstructed energy distributions were found in excellent agreement with the spectra calculated using Monte Carlo simulations and measured by a magnetic spectrometer. This TOF method can hence be used for absolute online spectrometry of laser-accelerated particle bunches.
Databáze:	MEDLINE
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