Probably better to use a CCD with electrical tape over the lens. I'm curious to see the difference in sensitivity between RAM and a CCD. I would think RAM is pretty resistant to bit flips or measures to counteract it, like ECC, would be more common.
At CERN I used to work on radiation measurement and characterization using ram chips (two different types with different sensitivities to neutron energies), but also characterisation with a ccd. With the ccd you can distinguish the type of the particle based on the track that it leaves behind, but the problem is the very low cross section (area, sensitivity) of the chip.
For folks who might be interested in more details on this: The _cross section_ allows you to quantify the frequency of a specific event occurring in your chip when bombarded by a specific particle (or class of particles). For example, in a case of an SRAM, you might want to calculate the cross-section for bit flips due to 24-GeV protons. The result that you get will be in units of cm^2; you can also interpret it as the physical surface area of the chip, multiplied by the probability (0..1) that any 1 particle passing through will trigger an event. Let's say you measure a cross section of 0.01 mm^2. Then if you expose that component to a flux of 10^3 particles/cm^2/sec, you will get an average of 1 event every 10 seconds.
The cross-section is only valid for one combination of the (event type, particle, energy) tuple. But often in dosimetry, errors on the order of 20% are acceptable, so we can "abuse" the results a bit. Within one manufacturing lot of chips, the cross-sections should be reasonably consistent. Typically you would estimate the mean and variance by measuring a few samples from the lot.
Then, to accurately measure a radiation field using these findings, you would generally need to measure the flux of every particle-energy combination separately. This is impractical, and for SEE* concerns we generally get away with distinguishing thermal neutrons and high-energy hadrons (which are separated by several orders of magnitude in energy). For this, it is sufficient to have 2 types of SRAM where each has a dominant cross-section for one of the particle classes of interest.
To measure the type of radiation that causes long-term gradual damage (TID) such as X-ray and gamma rays, you would use a different principle of measurement altogether (RadFET, P-i-N diode, floating-gate dosimeter...)
Radiation measurement can be fun!
[*] single-event effects, including bit flips and latch-ups
I worked on CCD and Later a CMOS chips for particle detection for the ATLAS detector during my undergrad! Well, on FPGA test controllers for them. I think They solved the cross section problem by having lots of layers of these chips in the detector iirc.
You can also get a trajectory with a stack of CCDs where the trajectory is not in the plane of the CCD. Actually the stack may be very high with quite some distance between individual CCDs, because you need trajectory in and out of detector elements like calorimeters that are a few meters in size. Also, trajectory may be bent because of the particle's charge and a magnetic field, for that you need a large distance to get the "amount of bend" if it is small.
But yes, there always is an efficiency, precision and identification tradeoff.
I'm not sure if it's still active but there was a project to detect cosmic rays using smartphone cameras flipped upside down or with tape on the lens: https://crayfis.io/
