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Extending the Dynamic Range of Radiochromic Film Oliver Ettlinger Ion Instrumentation Workshop, LULI 07-06-2012 1 Overview Radiochromic film calibration Film overview Data extraction HD-810, HD-V2 and EBT-2 comparisons Extending the dynamic range of RCF Ultraviolet wavelengths and their benefits for HD810

Application to HD-V2 and EBT-2 Film Overview HD-810: 10 400Gy Optical density proportional to dose and flux HD-V2: 10 1000Gy

Yellow marker dye EBT-2: 1cGy 40Gy Greater low energy sensitivity Traditional Data Extraction Calibration with known dose exposures cyclotron Flatbed scanner RGB scans and independent channel analysis for

improved range of dose data obtainable 2D spatial intensity profiles and beam divergence obtained Traditional Data Extraction 100G y 1000G y 10000G y HD-810 and HD-V2

* Red Channel <200Gy Blue Channel doses above 1kGy At least 150kGy dose limit in blue much larger than previously obtained results* G. Scott et al. CLF Annual Report 2010-2011

Red Channel <1000Gy Green channel 1000Gy 10kGy Blue channel - >10kGy Better Dose Range reduced sensitivity HD-V2 and EBT-2

Red channel <1000Gy Green channel 1000Gy 10kGy Blue channel - >10kGy Novel stack designs Thicker active layer increased sensitivity Red/Green channel up to 100Gy

Blue Channel up to 1000Gy Extending the Dynamic Range Transmission of multiple wavelengths through HD-810 film * Blue turns over at ~30kGy UV and IR do not exhibit multivalued nature in range observed Ultraviolet most suitable above 10kGy gradient and range of transmission values *

G. Scott et al. CLF Annual Report 2010-2011 UV (365 nm) bandpass filter Andor 16-bit CMOS camer a RCF holder

UV (365 nm) LED array Glass scatter screen Results Digitised using Nikon Flatbed Scanner UV Light Source

RGB Channels Reaching up to ~ 200kGy in rings using calibration on next slide Dose Extraction in UV Analogous to method for flatbed scanner Calibration obtained using known doses

Can this be extended to HD-V2 or EBT-2 Extending the Range of HD-V2 Blue preferable due to gradient transmission range could be an issue? Should be possible to use any of the three wavelength

regimes up to 100kGy Extending the Range of EBT-2 Both turn over at low doses no obvious extension of the range Desirable due to high sensitivity No UV data due to negligible

transmission at all doses Conclusions HD-V2 has similar characteristics to HD-810 but greater dynamic range HD-V2 and EBT-2 should be used in conjunction for better data collection UV wavelengths extend the dynamic range by at least an order of magnitude Method already proven with real data analysis Acknowledgements James Green, Ceri Brenner, Graeme

Scott and David Neely Central Laser Facility, STFC David Parker, Stuart Green and Francesca Fiorini University of Birmingham