# SiPM Photon Detection Efficiency Calculator

URL: https://speedycalculator.com/calculators/physics/pde-sipm/
Last updated: 2026-10-30

> The SiPM photon detection efficiency calculator finds the PDE of a silicon photomultiplier from its measured responsivity, gain, crosstalk and afterpulsing probabilities and the light wavelength.

## Inputs

- Responsivity (A/W)
- Wavelength λ (nm, µm, mm, m, pm, Å)
- Gain G
- Crosstalk probability P_XT (%)
- Afterpulsing probability P_AP (%)

## Results

- Photon detection efficiency

## Formula

```
PDE = R·h·c / (λ·G·e·(1 + P_XT)·(1 + P_AP))
```

## Explanation

Silicon photomultipliers detect single photons in LiDAR, PET scanners and particle physics. Their responsivity overstates detection efficiency because each photon's signal is multiplied by the gain and boosted by crosstalk and afterpulses – this formula removes those effects.

### How to use the SiPM Photon Detection Efficiency Calculator

- **Responsivity (A/W)**
- **Wavelength λ**
- **Gain G**
- **Crosstalk probability P_XT (%)**
- **Afterpulsing probability P_AP (%)**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Enter the responsivity, wavelength, gain and the crosstalk and afterpulsing probabilities.

### Inputs explained

FieldWhat to enterResponsivity (A/W)A numberWavelength λUnits: nm, µm, mm, m, pm, ÅGain GA numberCrosstalk probability P_XT (%)A numberAfterpulsing probability P_AP (%)A number

### Example values

How the main result changes when **Responsivity** changes and everything else stays at the example values above:

Responsivity (A/W)Photon detection efficiency (%)225,00036.1531337,50054.2296450,00072.3062562,50090.3827675,000108.4593900,000144.6124

## Worked example

Inputs — Responsivity (A/W): 450,000; Wavelength λ: 420 nm; Gain G: 1,700,000; Crosstalk probability P_XT (%): 7; Afterpulsing probability P_AP (%): 1.

Results — **Photon detection efficiency = 72.3062 %**.

## Key terms

- **Responsivity**: Output current per watt of incident light.

## FAQ

**What is a SiPM?**
An array of single-photon avalanche diodes sharing one output.

**Why correct for crosstalk?**
Optical crosstalk fires extra cells, inflating the signal.

**What is a typical PDE?**
30–60% at the peak wavelength.

**Why does wavelength matter?**
Photon energy and silicon absorption depend on it.


## Sources

- [OpenStax – University Physics Volume 2](https://openstax.org/details/books/university-physics-volume-2)
- [HyperPhysics (Georgia State University)](http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html)