OSL Reader

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The MicroStar OSL reader manufactured by Landauer is used to analyze the nanodot OSLs. By inserting an OSL into the reader, the crystal structure is exposed to an LED and a photomultiplier tube on the opposing side is used to measure the opacity. The OSL reader is an closed blue box of dimensions x by y by z. On the left side of the front face is the drawer in which an OSL in a holder is inserted. Once the drawer is shut, the black knob on the front is turned from H/P to E1, which activates the LED inside and allows the photo multiplier tube to count the hits through the crystal.

-> Picture of OSL reader

-> Picture of OSL holder


The OSL reader calculates the dose from the PMT counts, OSL sensitivity, and calibration factor. The equation used for this calculation is:

[math] Dose\ (mRad) = \frac{PMT Counts}{(Calibration\ factor) (Sensitivity)} [/math]


The OSL reader has software capable of calibrating the reader, which in turn creates a low and high dose calibration. These different calibrations give separate calibration factors. To create the calibrations within the software, Landauer supplies pre-dosed OSLs, of 5 different values. Due to uncertainty in exposure between dosing and usage, a custom calibration should be used to reduce error in succeeding measurements. The PMT counts are then used in the Cs-137 calibration to give a calculated dose in milliRad (mRad).




The low dose (10000 mRad>) calibration factor is 9.496494 as of 11/1/2017

The high dose (>10000 mRad) calibration factor is 0.6806084 as of 11/1/2017

According to this link https://www.nagase-landauer.co.jp/english/inlight/microstar.html, readout is 13 sec for OSLs in the microstar I.

Technical specs https://www.nagase-landauer.co.jp/english/inlight/pdf/Readers/microstarreader.pdf






Thesis

Reproducibility with 137Cs