4612

This device is capable of measuring optical light levels that may vary from the single photon level up to many orders of magnitude larger illuminations. In fact, the upper range can be almost, apart from practical spatial details, as large as one desires. This device is possible due to the fact that the SiPMs can be exposed to daylight at full voltage without damage.

Light sources that fluctuate by huge factors, from single photons up to 106 to 109 photons, are not common but do occur in the forward regions of particle colliders. They may also occur in bioluminescent materials over slower times scales, and possibly in optical measurements in non-destructive evaluation where the light level is varied over orders of magnitude to assess damage to a material.

For a very luminous light source, the choice is between a photo-detector that is sensitive to single photos but saturates above 100-to-1000 photos, or a photo-detector that attenuates the incident light in order to measure high light levels but which is therefore insensitive to single photons and low light levels.

This device, a "logarithmic photo-converter with huge dynamic range" is simultaneously sensitive to single photons and to arbitrarily large light levels. The dynamic range can be chosen at manufacture.

• Simultaneously sensitive to single photos and to arbitrarily large light levels

• Dynamic range can be calibrated after manufacture

• Input light does not have to be filtered or modified

• Accepts all incident light

Applications where measuring optical light levels may vary from the single photon to many orders of magnitude larger illuminations.