I recently visited the Chernobyl exclusion zone and thought to myself, how does my digital camera react to ionizing radiation?

Pictures of the destroyed reactor #4 were all a bit faded and I suspected it might be because of the high levels of radiation in the area so I decided to find out and tested my camera.

Chernobyl Nuclear Power Plant, washed out image

Perceived effect

Chernobyl Nuclear Power Plant Reactor 4

Original, unedited image

Test

I built a rig to expose the camera to different levels of radiation. Two radioisotopes were used as sources, Cobalt-60 which is a strong Gamma-emitter and Cesium-137 which emits Beta-particles. These yielded the highest activity levels on my counter of the samples.

Samples of different radioisotopes

Samples of different radioisotopes

In the measurements I used my trusty Russian dual-tube RADEX RD1706 Geiger Counter with a custom sticker in it.

Radex RD-1706

Digital dosimeter and radiation source

Cobalt-60 radiation source

Cobalt-60 source and aluminium beta-shield

Rig contained a lab stand holding the Geiger-counter, camera which had its sensor set the same height from the table and a laboratory elevator to rise and lower the isotope sample.

Testing rig with dosimeter and DSLR

Testing rig with dosimeter and DSLR

Gamma-emitter was covered with 8 mm aluminium sheet to block any Beta and Alfa-particles from reaching the sensors. For Cesium-137 paper envelope was used as an Alfa-shield. Lens was removed from the camera and replaced with thin plastic bodycap.

I took 11 measurements with both isotopes from different heights swapping the lab-elevator under the the geiger-counter and camera. Pictures were taken in RAW-format with 30 second exposures to maximize the amount of interference in the shots.

Conclusion

Radiation produces spots in the image that are caused by high energy particles hitting the CMOS-sensor. Unless the radiation is affecting the control and processing circuitry of the camera, anomalies seen on the images are not caused by ionising radiation.

Natural background and DSLR electrical noise

Natural background + DSLR electrical noise

Gamma scintillations on DSLR sensor

Gamma source + DSLR electrical noise

Read the whole lab-report (in Finnish) »

Verdict
  1. Ionizing radiation can be picked up by camera’s CMOS sensor
  2. High energy particles cause bright dots in digital images
  3. Remember to switch off camera’s manual mode if not using it
Difficulty ★★★☆☆
Time ★★☆☆☆
Price ☆☆☆☆☆