Characterization of the radiation hardness of PbWO4 crystals for the POKER calorimeter

For the construction of the POKER calorimeter, some PbWO4 crystals were purchased by Crytur. All the crystals were characterized in terms of radiation hardness at the Strahlenzentrum facility at Gießen (Germany). The test evaluates the damage induced by the crystals' exposure to an intense gamma source (constituted by an array of 60Co sources). Longitudinal optical transmittance was measured before and after the exposure, to quantify the damage. 

This dataset contains the data of the radiation hardness measurements performed on two sets of PbWO4 crystals: one including 20x20x220 mm^3 crystals and the other one including 20x20x200 cm^3 crystals. The files are in csv format and divided by data taking days (the legend can be found in the file Cristalli.csv). Each csv file shows two columns for each crystals: one with the wavelength and one with the correspondent Transmittance. Each crystal was measured at least twice (before and after the exposure), and the measurements are labeled with the crystal code and the label "before" or "after". Some measurements were repeated (and then the measure is labeled with a corresponding number) to evaluate the systematics. 

From this dataset it is possible to calculate a parameter, dk, which quantifies the radiation damage. It is defined as d = L^-1 * ln(Tbef/Taf), where L is the crystals length, Tbef is the transmittance before the exposure and Taf is the transmittance after the exposure).

To calculate the parameter, some fits were performed in a small wavelength range (415-425 nm), since the wavelength of our interest is 420 nm. 

This is done trough the attached code, called "dk_analysis.py", which is a python-based macro.