Difference between revisions of "Calibration Info"

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To fully understand the relationship between PMT Counts and total exposure for the Nanodot OSLs, a custom calibration is needed. This calibration is used in lieu of the calibration created by the OSL reader, which is created using the pre-dosed OSLs from the manufacturer. To begin the calibration, a set of fifteen unexposed Nanodot OSLs is chosen at random and exposed to a 9.3Ci <math> ^{137}Cesium</math> source. Using a distance of 30cm from the faceplate of the source, the exposure rate is calculated in Roentgen using <math> \dot R = \frac {\Gamma A }{ D^2} </math>. The gamma factor used for these calculations is <math> {\Gamma} = .33 \frac {(m^2)(R)}{(Ci)(hr)} </math>
 
To fully understand the relationship between PMT Counts and total exposure for the Nanodot OSLs, a custom calibration is needed. This calibration is used in lieu of the calibration created by the OSL reader, which is created using the pre-dosed OSLs from the manufacturer. To begin the calibration, a set of fifteen unexposed Nanodot OSLs is chosen at random and exposed to a 9.3Ci <math> ^{137}Cesium</math> source. Using a distance of 30cm from the faceplate of the source, the exposure rate is calculated in Roentgen using <math> \dot R = \frac {\Gamma A }{ D^2} </math>. The gamma factor used for these calculations is <math> {\Gamma} = .33 \frac {(m^2)(R)}{(Ci)(hr)} </math>
  
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<math>\dot R = \frac {\Gamma A }{ D^2} </math> where <math>\boldsymbol{\Gamma} = 3.3 \frac {(cm^2)(R)}{(mCi)(hr)} = .33 \frac {(m^2)(R)}{(Ci)(hr)} </math> , <math>\mathbf{A} = 9.3 Ci </math> ,  <math>\mathbf{D}=(\text{Distance to faceplate} + 11.2cm) </math>
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  <math>\mathbf{A} = 9.3 Ci </math> ,  <math>\mathbf{D}=(\text{Distance to faceplate} + 11.2cm) </math>
  
 
There is an adjustment distance of 11.2cm which accounts for the distance from the faceplate to the surface of the  <math> ^{137}Cs</math> source
 
There is an adjustment distance of 11.2cm which accounts for the distance from the faceplate to the surface of the  <math> ^{137}Cs</math> source

Revision as of 23:21, 15 May 2018

To fully understand the relationship between PMT Counts and total exposure for the Nanodot OSLs, a custom calibration is needed. This calibration is used in lieu of the calibration created by the OSL reader, which is created using the pre-dosed OSLs from the manufacturer. To begin the calibration, a set of fifteen unexposed Nanodot OSLs is chosen at random and exposed to a 9.3Ci [math] ^{137}Cesium[/math] source. Using a distance of 30cm from the faceplate of the source, the exposure rate is calculated in Roentgen using [math] \dot R = \frac {\Gamma A }{ D^2} [/math]. The gamma factor used for these calculations is [math] {\Gamma} = .33 \frac {(m^2)(R)}{(Ci)(hr)} [/math] 

[math]\mathbf{A} = 9.3 Ci [/math] ,  [math]\mathbf{D}=(\text{Distance to faceplate} + 11.2cm) [/math]

There is an adjustment distance of 11.2cm which accounts for the distance from the faceplate to the surface of the [math] ^{137}Cs[/math] source

Total exposures are calculated by [math]\int\limits_{t_0}^{t_f}\dot R\ dt [/math]




Click here for calibration data

Thesis

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