Changes

Although not discussed in the original requirements of the tagger microscope photo-detection, recent measurements have raised radiation hardness (specifically due to neutrons) as a concern for silicon photomultiplier (SiPM) readout. [http://www.jlab.org/Hall-D/software/wiki/index.php?title=SiPM_Radiation_Hardness_Test&redirect=no Radiation tests] of Hamamatsu and SensL 3x3mm² units have been started by Dr. Yi Qiang at Jefferson Lab.

Although not discussed in the original requirements of the tagger microscope photo-detection, recent measurements have raised radiation hardness (specifically due to neutrons) as a concern for silicon photomultiplier (SiPM) readout. [http://www.jlab.org/Hall-D/software/wiki/index.php?title=SiPM_Radiation_Hardness_Test&redirect=no Radiation tests] of Hamamatsu and SensL 3x3mm² units have been started by Dr. Yi Qiang at Jefferson Lab. A similar test is necessary for the Photonique SiPM's currently intended for outfitting the tagger microscope.  

A similar test is necessary for the Photonique SiPM's currently intended for outfitting the tagger microscope. To suggest appropriate dose the following considerations are offered:

 

 

To suggest appropriate dose the following considerations are offered:

# since a sensor undergoes annealing (as has already been reported in literature) concurrently with the irradiation, an equilibrium may exist between the two processes or, at the very least, the degradation is slowed.

# since a sensor undergoes annealing (as has already been reported in literature) concurrently with the irradiation, an equilibrium may exist between the two processes or, at the very least, the degradation is slowed.

# much higher dose rates are applied in radiation hardness tests since the time scale of these tests is much smaller than the lifetime of the equipment in the Hall D complex

# much higher dose rates are applied in radiation hardness tests since the time scale of these tests is much smaller than the lifetime of the equipment in the Hall D complex

# dark rate (current) scales with the area of the wafer

# dark rate (current) scales with the area of the wafer

it seems therefore that '''similar doses should be applied to the Photonique SiPM as have been found effective in measurements with Hamamatsu and SensL units'''.  

it seems therefore that '''similar doses should be applied to the Photonique SiPM as have been found effective in measurements with Hamamatsu and SensL units'''.