Just want to let you know, that we drive our environmental measurement grid with GM tubes having much higher active volume (e.g. Centronic ZP1220). A low dose range is mandatory for stationary in-the-field automated monitoring. Such stations should have all-in-one circuits in wheater-proof enclosure (and may benefit from solar panel supply and WiFi).
Windowed tubes like the LND712 should be designated for lab table operation with a detector head housing separated from counter/supply. You will not get robust data from placing alpha, beta sensors into the air, because:
- most of the nuclei lay on the ground and alpha and beta rays do not reach a detector on a pylon.
- environmental radionuclides (Radon successors) may dominate the counting rates hiding fission product activities, if beta activity joins the mix
- those windows are easy to be damaged and contaminated in-field
On a lab table (preferably in a plumbum cage), their role is to inspect material laying on a flat surface from a close-up position. We suggest to inspect accumulating carriers like air conditioner filters, if small tubes like a LND712 are used.
Most GM tubes do work in a 400 - 700 V range, and can be driven with 500 V, if the HV supply is stabilized. There is no need to adapt the HV circuit to a certain tube. Here is a
tube data list of our local manufacturer (Voltage ranges in the next to last column), the
cross ref table shows similar models from other vendors including LND.
If someone´s interested to get a tube made in Germany, I´ll ask for an actual quote. Delivery is usually 3-6 weeks, depending on the model.
Hope that helps
