1
\$\begingroup\$

I'm developing a magnetic field sensing kit for a project. The kit contains sensors (specifically an accelerometer, a gyroscope, and a magnetometer) that will detect and measure magnetic fields, and my team plans for this kit to be placed in a location with high amounts of radiation, specifically neutron, alpha, and gamma radiation.

I'm really new to radiation effects, so I was wondering how does radiation cause strange behavior to occur in electronics, and which components are the most likely to be affected by radiation? Right now, I'm looking for sensors for the kit, and it's near impossible to find radiation-hardened sensors. Given my unfamiliarity with radiation, I'm trying to understand how it affects electronics so I can see if we need to purchase specialty components or if we can make do with just regular components.

EDIT: After speaking with my team, to be honest, we don't have a specific value on the intensity of the radiation to be expected. All I was told that the source will emit neutrons. Looking at what's available in terms of components, rad-hard components tend to be quite expensive and big, not in a small IC form factor, so I think I'll just have to go with a different solution.

\$\endgroup\$
11
  • 1
    \$\begingroup\$ I think you should start with estimating the spoken intensities... \$\endgroup\$
    – Eugene Sh.
    Feb 22, 2018 at 19:41
  • \$\begingroup\$ All semi-conductor junctions are sensitive to light/radiation. How sensitive varies. But a transistor inside a chip will act like a photo-transistor if exposed to enough high energy particles/photons. If it's for a high radiation environment, you will likely need to add shielding. The sensor, which you may not be able to shield, since it needs to sense something, may be a trickier proposition. \$\endgroup\$
    – Trevor_G
    Feb 22, 2018 at 19:47
  • \$\begingroup\$ @EugeneSh. Thanks. I'll ask around and see what kind of intensity is to be expected. \$\endgroup\$ Feb 22, 2018 at 20:01
  • \$\begingroup\$ Minimize the exposure. Place the sensors on a separate unit that connects to the computer (the Pi) that is somewhere with better shielding. \$\endgroup\$
    – JRE
    Feb 22, 2018 at 20:01
  • \$\begingroup\$ I'd recommend that you study reports of placing electronics in orbit around the Earth, the sun, or else for for long-duration missions. This is a well-studied area, with good funding, though there always will be more research needed. For circuits like MCUs, though, you will want "large feature" designs. The larger the transistor, the better, for example. Low voltage operation is better than high voltage operation, if you have a choice, because high voltages can "follow" an event and cause cascading damages. Duplication and voting systems may help with CPUs and software. \$\endgroup\$
    – jonk
    Feb 22, 2018 at 20:38

3 Answers 3

2
\$\begingroup\$

Energy levels are inverse to wavelength so shielding depends on both. Start with energy specs and IO lines & electronics that need protection.

Are you planning any nuclear tests? enter image description here

Each wavelength has different reactions to electronics including;
- ionization ( arc or dielectric breakdown)
- atomic displacement of SiO2
- nuclear reactions from trace nuclear atoms.

\$\endgroup\$
4
  • \$\begingroup\$ Thanks for your comment and the picture. It does a good job simplifying how radiation penetrates materials. My team doesn't plan to do any nuclear tests. We're just attempting to measure the magnetic field around a source that emits a large amount of radiation. \$\endgroup\$ Feb 22, 2018 at 20:28
  • \$\begingroup\$ The "funny" part not shown in in the picture above is that neutrons after passing all the outer layers will in turn create gamma radiation when getting absorbed. So the water should better be placed before the lead. \$\endgroup\$
    – Curd
    Feb 22, 2018 at 21:44
  • \$\begingroup\$ Yes the picture in effect shows eddy currents& skin depth and not pulse spreading something like a low pass filter. \$\endgroup\$ Feb 22, 2018 at 21:52
  • \$\begingroup\$ Eddy currents and skin depth makes only sense for electromagnetic waves. Among the radiation types in this picture only X-ray and gamma is EM-radiation. Alpha, beta and neutron radiation are just flying particles (He-nuclei, electrons and neutrons); not EM waves. \$\endgroup\$
    – Curd
    Feb 23, 2018 at 19:56
2
\$\begingroup\$

Semiconductors can be damaged/destroyed when exposed to radiation.

I worked at a particle accelerator facility (TRIUMF, Vancouver BC) and once installed a regulated power supply mounted in a steel box in the cyclotron vault - it failed in a fairly short time (a few weeks, if I recall correctly). The radiation level in that area was sufficiently high that we were only permitted to work in there for under two hours a day, and that only after the cyclotron had been off for a week or more.

\$\endgroup\$
1
  • \$\begingroup\$ I read the main magnet current was regulated 1ppm for many decades. wow. I recall my electronics in Pickering 2ndary heat exchanger during maintenance was never reported to be an issue. But that's just heavy water. \$\endgroup\$ Feb 22, 2018 at 21:18
-1
\$\begingroup\$

In September of 2016 I have designed and built a circuit to measure things for isotope production with a cyclotron. The radiation levels during isotope production are pretty high ( mostly neutrons, lethal for humans ), yet the electronics works without a problem. The circuit consists of op-amps, DACs and ADCs, a microcontroller and bunch of passive components - just ordinary parts, not radiation hardened. So, if radiation levels are comparable there should be no problem.

\$\endgroup\$
2
  • \$\begingroup\$ So no care to select ENIG ground shields or double shielded cables? \$\endgroup\$ Feb 22, 2018 at 21:07
  • \$\begingroup\$ This is a) not an answer and b) grossly misleading. No details about flux, design methods, error tolerance etc. \$\endgroup\$
    – awjlogan
    Feb 22, 2018 at 22:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.