Improved spectral data unfolding for radiochromic film imaging spectroscopy of laser-accelerated proton beams

Journal Article · Tue Apr 15 04:00:00 EDT 2014 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4870895· OSTI ID:22254926

Schollmeier, M.; Geissel, M.; Sefkow, A. B. ^[1]; Flippo, K. A. ^[2]

---

1. Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
2. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

An improved method to unfold the space-resolved proton energy distribution function of laser-accelerated proton beams using a layered, radiochromic film (RCF) detector stack has been developed. The method takes into account the reduced RCF response near the Bragg peak due to a high linear energy transfer (LET). This LET dependence of the active RCF layer has been measured, and published data have been re-interpreted to find a nonlinear saturation scaling of the RCF response with stopping power. Accounting for the LET effect increased the integrated particle yield by 25% after data unfolding. An iterative, analytical, space-resolved deconvolution of the RCF response functions from the measured dose was developed that does not rely on fitting. After the particle number unfold, three-dimensional interpolation is performed to determine the spatial proton beam distribution for proton energies in-between the RCF data points. Here, image morphing has been implemented as a novel interpolation method that takes into account the energy-dependent, changing beam topology.

• OSTI ID: 22254926
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 4 Vol. 85; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
BRAGG CURVE
ENERGY SPECTRA
INTERPOLATION
ITERATIVE METHODS
LASERS
LET
PROTON BEAMS
RESPONSE FUNCTIONS
SPECTROSCOPY