DIY_particle_detector_wiki/Troubleshooting.md

If the detector does not work properly or you are not sure about it:

1. compare again the correct position of each component with the parts overview sheets:
   electron-detector (German version) or alpha-spectrometer

   • doublecheck the orientation of the Diodes D1-D4 (where is the anode/cathode pin?)
   • doublecheck the orientation of the black amplifier chip U1 (where is pin 1?)
   • doublecheck the orientation of the large electrolytic capacitor C8 (where is its negative/minus pin?)

2. connect the detector to a real hardware oscilloscope

   • debugging the detector directly on a microphone/headset input by using a software oscilloscope is likely to introduce additional sources of problems
     • test those audio inputs at least with a real headset or microphone before attaching the detector
     • make sure that the software oscilloscope is recording from the correct channel
     • increase the microphone input volume/gain settings of the operating system, a good range is 50% to 100%
     • try different gain settings while always adjusting the trigger level accordingly, a setting of 100% may produce too much noise and can hide signal pulses completely
     • be sure to use the correct Cables with the detector

3. if you disconnect the battery and measure across the battery connector with an ohmmeter/multi-meter, it should read about 9-10 kilo Ohm

   • if the resistance is close to zero or zero Ohm, there is a short-circuit (e.g "a bridge") between two connections that must be found and removed
   • if the resistance is much higher or not measurable, some solder joints might be bad and should be resoldered

4. the signal line on the oscilloscope screen must change briefly every time when you switch the detector on/off or re-connect the battery

   • if you see no reaction, re-check all the wire connections, solder joints
   • make sure that the battery is not empty and delivers at least 8.5 V when disconnected
   • as long as this issue is not solved, it makes no sense advancing to the other points below

5. try to measure something that is proven to be considerably radioactive

   • a vintage piece of uranium glass from the flew market that produces at least 1 count per second with a Geiger-Müller counter
   • a big bag of potassium salt = KCl. Sold as "No-Salt", "Lo-Salt" or "sodium-free dietary table salt" or simply as pure KCl from a pharmacy.

6. put the object as close as possible in front of the diodes, if possible inside the metal eclosure surrounding the detector!

7. put a thick black piece of cloth or towel on top of the detector case to make sure that all residual light is blocked!

   • consider a darker room and avoid bright sunlight during the first tests

8. do not touch the detector or the table during the measurement (important with thin-walled candy tin boxes)

   • if you hit the detector hard and quick with a finger, the vibration should appear as a short sine-like wave

9. compare the signals of your detector on a real oscilloscope with my reference screenshots

   • Electron-detector reference pulses from KCl:
     

   • Alpha-Spectrometer reference pulses from KCl:
     
     (These pulses are only from electrons, alpha pulses would be even larger!)
     Please refer to Oscilloscope Measurements for further details.

   • if the noise range of your signal is much small or larger than the shown ones:

     • there is most likely still too much light reaching inside the case
     • or another electromagnetic source of radiation closeby and interfering
     • there could be still a problem with how the components are soldered. Please re-check according to 1.
     • make sure the switch and output connector are both firmly fixed to the metal walls.
     • it will not work inside a plastic box, the enclosure must be made from metal (Faraday cage)

   • if you see continuous 50 Hz, 100 Hz, or much higher frequency sine waves:

     • most likely some fluorescent neon-tube or LED light is still reaching inside the detector enclosure
     • a high-power electronic appliance or machine (electromotor, fridge compressor etc.) could create too much electromagnetic interference radiation (EMI) - try changing the room or even the building
     • if the signal changes when the opened detector enclosure is exposed to light, that is generally a good sign and positive test result. but the shown reference signal pulses and noise range can be only observed if the closed enclosure is completely blocking any form of light.

   • when accidentally swapping the ground and output signal connection or with certain soundcards/headset inputs, the pulses may appear inverted and go upwards instead of downwards:

     • check for pulses above the noise level (instead of below it) by moving the trigger level of the oscilloscope upwards

Please start a new thread in the GitHub Discussions if none of those tips did the trick.
Also, consider asking a local maker space or fab-lab for support, they'll be likely glad to help. :-)