Sensor Cooling & Dark Current Calculator

Estimate dark current at any temperature or find the temperature needed for a target dark current.

Dark current in silicon-based imaging sensors approximately halves for every 5–7 °C of cooling, following the rule I_d(T₂) = I_d(T₁) × 2^(−ΔT/T_d). This calculator works in two directions: forward mode predicts dark current and accumulated dark charge at a target operating temperature given the room-temperature rate and the sensor's halving constant; reverse mode finds the temperature required to reach a specified dark current level and suggests the appropriate cooling method — single- or multi-stage thermoelectric, liquid-cooled TE, or liquid nitrogen. Inputs accept room-temperature dark current in e⁻/pixel/s, integration time, and halving constant (T_d ≈ 5–7 °C for silicon CCD and CMOS sensors). The forward mode also generates a dark current table across standard temperature setpoints from +25 °C to −120 °C.

Forward: Temperature → Dark Current

Room-temp dark current

Room temperature

Target temperature

Halving constant?

Integration time

Dark Current at Target Temperature

Dark current

0.0013e⁻/p/s

Dark charge

in 10 s

0.0135e⁻

Dark noise

0.1161e⁻ rms

Temperature drop

105.0°C

Number of halvings

17.500

Dark Current vs. Temperature

25 °C

250.0e⁻/p/s

0 °C

13.920e⁻/p/s

-20 °C

1.381e⁻/p/s

-40 °C

0.1370e⁻/p/s

-60 °C

0.0136e⁻/p/s

-80 °C

1.35e-3e⁻/p/s

-100 °C

1.34e-4e⁻/p/s

-120 °C

1.33e-5e⁻/p/s

Abridged Optics — Sensor Cooling Calculator v1.0I_d(T₂) = I_d(T₁) × 2^(−(T₁−T₂)/T_d). T_d ≈ 5–7 °C for silicon.