CMOS Cameras Simulation

Flavio Di Clemente

Giulia D’Imperio

Gianluca Cavoto

8 / 10 / 19

Copper shield with holes for camera lens (5 cm thick)

CMOS cameras (body + lens)

Image from visual GEANT4 simulation (CYGNO script) available on CYGNO Github workspace

The whole decay chains produced from the cameras have been simulated inside the detector using measured activities.

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Unfortunately, we don’t know the single contributions given by the components of the camera to the overall background.

in [0-20] keV

No shield: 2.05 x 10⁷ cpy

Shield: 6.60 x 10⁶ cpy

Even with shield, the rate is far beyond the threshold we want to reach (~10^4 cpy from ER)

The reached attenuation factor is actually very low even with a thick Cu+Fused Silica shield (5cm + 5cm).

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Other solutions should be studied.

SUMMARY

• The background due to the CMOS cameras is 10^3 higher than the threshold value of 10^4 cpy we want from ER. No screen is able to introduce the requested suppression.

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• We don’t know the single contributions from the CMOS camera internal components: measuring these contributions could be effective to find an hardware solution.

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• Neither the lens nor the body of the camera produce a negligible background, since they both carry half of the total background rate.