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

Figure 4-9: Photograph of sample carousel before being lowered into microprobe chamber
4.1.4.
 
Calculation of dose
The radiation dose received by each scintillator was calculated using the 
relationship
𝑅 =
𝑁
𝑝
× 𝐸
𝑙𝑜𝑠𝑠
𝑚
. Here 
R
is the absorbed dose in Grays, 
E
loss
is the 
amount of energy lost per proton in units of Joules, 
N
p
is the number of protons 
impinging the sample and 
m
is the mass of the irradiated sample in units of 
kilograms.

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31 
The
𝐸
𝑙𝑜𝑠𝑠 
for each sample was determined using the SRIM simulations discussed 
previously. The mass was determined for the irradiated spot area (1.8 mm x 1.8 
mm), using the densities given by the manufacturers and accounting for each 
sample’s thickness.
The number of protons impinging the sample, was determined using the 
relationship
𝑁
𝑝
=
𝑖𝑡
𝑞
, where 
i
is the current of the proton beam used, 
t
is the total 
irradiation time and 
q
is the charge of a proton. The total charge passed through 
each sample for their respective exposure times during irradiation was used for 
the calculations. Appendix B contains the tables summarising the beam 
conditions and calculated doses, as well as beam current distribution plots for all 
samples.
4.2.
 
Overview of the techniques used to analyse 
damage 
The effects of proton damage on the optical properties of the samples were 
characterised by conducting light transmission, light yield and fluorescence 
studies. Whilst the technique of Raman sp ectroscopy was used to investigate the 
structural damage undergone by the scintillators.