- Operate the kit from a battery powered device without connecting it to the mains electricity. In other words when connecting the device to a USB power source (eg. laptop) it is a recommended safe practice to operate from the batteries only without connecting to the mains. This is general safe practice when experimenting or working with hobby electronics. Otherwise installing a safety extra low voltage power supply system (SELV) is recommended.
- Wear goggles when soldering.
- Solder in a well ventilated environment.
- Take care not touching the components becoming hot during soldering.
- Do not touch the high voltage components, C1 and C2 in particular when operating the circuit. The charge stored is minimal in the kit, it is not considered hazardous by the IEC 61010-1 standard applicable to lab equipment with accessible live parts, but it is not a pleasant experience. You can always apply one or more layers of insulating tape above the mentioned parts if you are concerned. All the relevant signals are accessible on the white board's header, and those are all 3.3V max nominal and the critical ones with an added 5V protection. There's no need to check the parts at the back.
- Do not use the kit without the GM tubes connected.
- Disconnect the micro USB connector when switching off the circuit.
- Do not use the kit in a humid or wet environment.
- Make sure the kit is kept dust free.
Since the Muon Hunter is an electronic hobby kit, the entire responsibility of safely assembling and operating the circuit is with you, the user. Although the Muon Hunter was designed using safe practices and observing and adhering to the limits of the IEC 61010-1 standard for the components that can be touched, the assembly used reliably sourced, original high voltage components, since the assembly involves you, the user, there is no warranty for the Muon Hunter hardware or software to the extent permitted by applicable law. Except when otherwise stated in writing, the copyright holders and/or other parties provide the Muon Hunter hardware and software "as is" without warranty of any kind, either expressed or implied, including, but not limited to the implied warranties of merchantability and fitness for a particular purpose. Should the hardware or the software prove defective, you assume the cost of all necessary servicing, repair or correction.
Technicaland safety data
- GM signal voltage on the accessible pins / RPi inputs: 3.3V
- Power input: 5V USB, battery recommended
- Typical power consumption: 0.2 W
- STS-5 GM tube operating voltage: 400V
- Max. short circuit current at a GM tube: 0.09 mA at 400V. This value is well below the human sensational threshold, let alone the dangerous levels according to safety standards. This means you probably won't feel anything when touching the tubes. Nevertheless it's not recommended, since you can include false data in your measurement this way. But if you touch the C1 and C2 capacitors, you would probably feel that, so don't poke around the back of the board when operating the kit. All the relevant signals are accessible on the white board's header, and those are all 3.3V max nominal and the critical ones with an added 5V protection. There's no need to check the parts at the back.
- Max. thermal current threshold at 3.3V: 300mA. (You won't feel this because of the sub 12V voltage.) This is 1W power consumption by the detector circuit is too high. This indicates either very high radiation, so a place where you definitely should not stay, or an electrical fault. Should things go this way, the first sign you'll probably see is the screen fading: it's not a fault, it's a word of caution. You can normally restart after checking for shorts. Eg. dropped wire/tool/component somewhere, etc.
- High voltage protection: 5V clamps at the 3.3V rail and the same protection at the GM signals and at the voltage feedback.
- Theoretical maximum voltage (if you hack the firmware): approx 900V. It has been tested with 500V GM tubes. These modifications are all possible, but you should know what you're doing in this case. The components concerned by the little HV supply are rated up to 1 kV.