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Radiation or electrical interference? Geiger counter

  1. Jan 13, 2016 #1
    First, I hope this is the correct place for this question.

    I am experimenting with electrical discharges at low pressure, think plasma globe, and I bought a geiger counter to make sure I am not producing x-rays. My vacuum pump is rated down to 5 pascals. The problem is that the geiger counter is set off by the RF noise from the tesle coil. Using grounded metal shielding reduces this noise is greatly, but how can I tell if the geiger counter is in fact picking up x-rays?

    Currently the counter only picks up a reading when very close to the discharge. X-rays should still be strong at more than 10-20cm from the source, right? The geiger counter also only goes off when using the tesle coil, and reads nothing when I use a high voltage DC supply. What do you think?
  2. jcsd
  3. Jan 13, 2016 #2


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    Staff: Mentor

    Depends on the energy range, but low-energetic x-rays won't go through the glass. At 1 keV, the range in air is just a few millimeters. For 10 keV this increases to more than a meter.

    Aluminium foil could absorb electromagnetic interference while not absorbing too much x-rays (compared to the glass).

    Absorption values from here.
  4. Jan 13, 2016 #3
    Thanks, sounds like if they were able to escape the glass, then I would be picking them up farther away. The metal shielding is actually counter-productive in some cases because it just makes a bigger target for induction by rhe emf.
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