Simulation of bremsstrahlung spectra in general targets and
Simulation of bremsstrahlung spectra in general targets and its application to a model of a laser-driven irradiation source G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop
Table of contents G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 2
Introduction Laser driven sources Made possible by laser CPA (1985) Image from: Physics Today, 51: 22, 1998 G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 3
Introduction Multiphoton ionization Tunnel ionization Barrier-suppression ionization Image from: F. Fernández, et al. 2013 G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 4
Introduction Laser driven sources e- Sources with 1: • • Energy-dependent angular divergence Wide spectral bandwidth Short pulse duration Small source size 1 Cf. e. g. Daido et al. , Rep. Prog. Phys. 75 (2012) 056401 G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 5
Introduction Particles Cells G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 6
Introduction Monoenergetic bremsstrahlung spectra Cf. e. g. Podgoršak Radiation Physics for Medical Physicists 2010. Pp. 269 -275 G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 7
Introduction G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 8
Simulation strategy G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 9
Parameter identification Parameters: e e- γ G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 10
Parameter identification G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 11
Parameter identification Thickness CSDA range: NIST’s G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 12
Parameter identification Thickness CSDA range: NIST’s G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 13
Parameter identification Thickness CSDA range: NIST’s G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 14
Parameter identification G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 15
Avoiding repeated parameter simulation Thickness: Naïve approach G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 16
Avoiding repeated parameter simulation Thickness: Latching 1 approach 1 Cf. Poludniowski & Evans Med. Phys. 34 (2007) for the name G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 17
Latching How to implement it Assuming there is some ORDER in the regions (infinite layers, cylindrical or spherical shells, …), a particle needs to know how far it or its antecessors have gone • When crossing a boundary: • FLUSCW with ISCRNG. EQ. 1 • Save the max. visited region: • ISPUSR(1) = MAX(IOLREG, ISPUSR(1)) G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 18
Latching Where that info is saved: So the info latches onto the particles (Taken from FLUKA course slides) G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 19
Latching How to implement it Score if particle is going to a new region • IF ((ISPUSR(1). EQ. IOLREG). AND. (NREG. GT. IOLREG)) THEN FLUSCW = ONEONE Otherwise, e. g. , score for some detectors and do not for others, thus single-crossing and multiple-crossing data is available ELSE IF ( MOD(JSCRNG, 2). EQ. 1) THEN FLUSCW = ZERZER ELSE FLUSCW = ONEONE END IF (Check the Advanced User Routines lesson for more info) G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 20
On the scattering model Single scattering VS multiple scattering Remember from yesterday: How thin is thin? G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 21
On the scattering model A rough a priori estimate A. Ferrari et al. 1991: H. A. Bethe 1953: G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 22
On the scattering model Working ? Not working G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 23
On the scattering model G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 24
On the scattering model G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 25
On the scattering model G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 26
On the scattering model Single scattering VS multiple scattering ‘Experimental’ analysis: • Difference is about 10% – Seems to be random for small depths and systematic for bigger ones. • CPU time ratio was about 5 (100 ke. V) • Bremsstrahlung production is very noisy for very thin targets. Mean free path biasing could be of interest in such cases 1. 1 Cf. : http: //www. fluka. org/web_archive/earchive/new-fluka-discuss/2813. html G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 27
Some notes on post-processing G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 28
Some notes on post-processing G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 29
Some notes on post-processing Some ideas for such packages System of unit handling Importing data • Better process flair-produced files • . inp can be used to automatically add info (e. g. magnitude scored or units) Wrap usual operations • E. g. , plotting, interpolating… G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 30
Some notes on post-processing Our approach: the FLUKAmatica package 1 1 http: //community. wolfram. com/groups/-/m/t/354002 G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 31
Some notes on post-processing Our approach: the FLUKAmatica package G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 32
Some notes on post-processing Our approach: the FLUKAmatica package (Artificially increased error bars) G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 33
Some notes on post-processing Our approach: the FLUKAmatica package G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 34
Some notes on post-processing Our approach: the FLUKAmatica package Integrate in energy to get a distribution in angles: G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 35
Some notes on post-processing G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 36
Some notes on post-processing Our approach: the FLUKAmatica package Plot as function of energy: G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 37
Some notes on post-processing Our approach: the FLUKAmatica package Some day at fluka-discuss@fluka. org ! G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 38
Conclusions A glimpse of the simulation results: thin G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 39
Conclusions A glimpse of the simulation results: thick G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 40
Conclusions A glimpse of the simulation results Beware: scaled to maximum G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 41
Conclusions Interpolation in energy G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 42
Conclusions Superposition in energy: R A N I M I L E R P G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 43
Conclusions G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 44
Thanks for your attention And thanks also to: • Our hosts at LFN • The FLUKA community, specially those at fluka-discuss@fluka. org • Institutions supporting this research: Correspondence: guillehg@usal. es Simulation of bremsstrahlung spectra… 45
Introduction CPA: Chirped Pulse Amplification G. Hernández, F. Fernández FLUKA 3 rd Advanced Course and Workshop Simulation of bremsstrahlung spectra… 47
- Slides: 47