Does not keep anything that is promised

From the welding accessories, while a WT20 TIG electrode diameter 1.6mm, length: 175mm, which are the red with the mark and 2% thorium content.
At 6 g electrode weight ie 120 mg thorium. Natural Thorium has a specific activity of 8120 Bq per gram.
The electrode thus 974 Becquerel (counts per second)
The electrode is broken into 2.5 cm pieces, the pieces are close to each other glued to a wide tape.
In this radiating surface of 2,5x1,1 cm you put exactly wheel rate-count window, and one via tally sheets for 10 minutes, the pulses.
This results in 24.22 cpm (counts per minute).
That this is so little compared to the 974 rays per second, according to this source produces its thorium content, easy is because most alpha particles can not leave the tungsten rod.
Only - and yet, after all: 2% of all the atoms in the surface are 232-thorium atoms whatsoever Emmi animals the way the decay to next Alpha one gamma ray. In the other decay series are roughly gelich many short-lived alpha as beta-emitters. 232Th makes half of the alpha + gamma thorium activity, the other half comes from the short-lived isotope 228Th.
But further in the test:
We push a strong paper (250g / m2) between our thorium-alpha source and the wheel rate-count window, and again 10 minutes count the pulses:
No Change! Still 25.6 cpm, this time even in between a little more than paperless.
And that means that wheel rate does not count alpha particles,
otherwise it would be significantly less impetus now because:
Already a sheet of paper shields alpha particles completely.
Now we take a acrylic sheet of 3 mm thickness in between, which is suitable for alpha and beta radiation intercept:
Reducing the count rate to 5.44 cpm - what then is only gamma radiation,
80% of the measured wheel rate of radiation was beta, and possibly additionally the bremsstrahlung of beta emission at Wolfram.
This corresponds very roughly even a proportion of total emissions of gamma and beta over the entire decay chain from 232Th, and thus makes the attempt in addition plausible.

Criticism:
1. It is promised, which is not to keep: wheel rate does not measure alpha radiation.

Although 2nd wheel rate has a counter, but serves to limit apparently only to the duty (self shutdown after 10 min). There is no indication of totalized pulse count, or another counter display.

3. The Auto-off after 14 minutes is annoying if you want longer count.

4. That no count output is present, is disturbing, because the "flackerige" display that integrates seemingly through a capacitor, and finally outputs the voltage is only useful from about 10 - 20 events per minute,
which then already corresponds to 10 to 20 times the background radiation.

5. The price is a bit high, because there are comfortable equipped detectors similar power already for 40 euros less,
or even for only 40 euros as a kit.

5. The battery clamps so strong that the battery actually only by opening the housing also gets without violence and tools again - only marginally worth mentioning probably it is even necessary that the battery is stuck, and can not be moved in order to avoid microphonic missing pulses ,

Compliment:
1. wheel rate measures beta radiation quite well, and apparently also gamma radiation.
2. The packaging is good, the delivery prompt and professional, the service I can only judge in a few days,
because I'm still waiting for the answer to questions about the technology.

Suggestions:
If you open the case, is actually still a lot of space inside for a better and more accurate pulse counter,
the detection electronics deserved safely. And without the daily radioactive contamination in foods with wheel rate can not accurately measure. But even a reset button with adjustable measuring time (1 day - 1 week - infinity)
Or at least one counter output and a gamma spectroscopy with the original signal from the detector ...
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PS / edit: Limiting the duty cycle can be eliminated on the front of the board by desoldering the jumper J3. My wheel rate now also has an additional RCA socket as counter output on the front ;-)