Proton induced radiation damage studies on plastic scintillators for the Tile calorimeter of the atlas detector

BC408 
UPS923A
TileCal

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The EJ260 scintillator has the least transmission loss at 430 nm, however at this 
wavelength, absorption by its fluor dopants are ongoing. In these scintillators, 
the free radicals formed would compete with absorption of light by the fluors, 
but wouldn’t further quench the final wave-shifted light which has an emission 
peak at 490 nm. This feature is marketed as a contributor to the radiation hardness 
of these scintillators by the manufacturer [21].
The downside of this scintillator however is that it will not couple well to the 
Y11 fibers currently used in the detector, which absorb light over the range 420 
-450 nm. Thus using EJ260 as a replacement candidate would require replacing 
the fibers as well. The radiation hardness of these would then have to be taken 
into account and may add additional costs.
The blue scintillators perform very similarly to each other. There aren’t any major 
distinctions in the performance between the PVT and PS based scintil lators in 
terms of their transparency loss at 430 nm. EJ200 appears to perform only slightly 
better than the other blue scintillators for the doses ranging between ~8 MGy and 
25 MGy. EJ208 however, has the least transparency loss at the highest dose of 
~80 MGy. It should be noted here that the peak emission wavelength of EJ208 is 
at 435 nm as compared to 425 nm for all the other blue scintillators.
Since all of the scintillators have slight variations in their absorption regions 
based on the types of fluors which they are doped with, comparing their 
transparency loss at one wavelength alone is not sufficient. Figure 5-5 therefore 
shows the relative transmission for each scintillator at their respective 
wavelengths of maximum light emission. 
This plot further confirms that for the higher wavelength shifting scintillators, 
i.e. EJ260 and EJ208, less transmission loss occurs at their wavelengths of 
maximum light emission. Therefore, their emitted light will be subjected to less 
quenching via competitive absorption by free radicals as compared to the 
standard blue emitting scintillators. Furthermore, these standard blue emitting 
scintillators perform within 20% variation of each other.

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