Unconventional electrolysis

magicsound

A while back I posted an excerpt from a blogpost from a person with an SBM-20 tube who made polarity reversal tests with a Cs-137 test source and found that the response at the "wrong" polarity was lower, similarly to what I observed, even if in theory it should haven't. That's what motivated my hypothesis. However, that is no Am source.

Relevant quote below:

http://uvicrec.blogspot.com/20…0-geiger-muller-tube.html

Quote

The tube is clearly marked with a "+" on one of the terminals. But theoretically it should collect charge on either terminal. So what happens if you reverse it?

At +400 V I recorded 3068 CPM. At -400V I got 1381, about 45% of the + reading. When I removed the source altogether I got 9 CPM. So clearly its working as a detector, albeit less efficiently.

[img]

I tried to take current measurements and by 700 V spikes were already occurring

[img]

[img]

By 900 V the signal was unstable as they no longer settled to a steady state. Maybe oscillating with the capacitor?

Overall appears to be less efficient and works under a much narrower range. Presumably GM tubes are optimized for positive voltage though so maybe it could be improved a lot if you intentionally tried to design a negative center GM tube. In any case, the biggest takeaway is that under standard 400 V operation the tube works. This is actually unfortunate as you might not notice you installed it backwards (mechanically possible).

Display More

At the moment I don't have any known/certified radioactive source to check for myself.

magicsound

No worries, that was a good occasion for updating the thread with more information.

I took a couple photos for manual long term averaged CPM verification.

From EXIF data:

00:21:31, 7159

00:52:08, 9217

2058 counts / 1837 seconds = 1.120 CPS = 67.218 CPM

This seems to agree with logged data as seen from the latest graph:

I've had problems with the script I made. Every once in a while it appears there's a race condition in the multithreaded code which causes it to fail.

Robert Horst

It is indeed a very cheap instrument: https://netio.stores.jp/

The pre-assembled version is 72 USD, while the kit version is 52 USD. Both include the SBM-20 GM tube.

The manufacturer claims:

Quote

GC10 was designed early days after 3.11 to explore and investigate highly contaminated area in Fukushima.

Focusing on simple feature and good manufacturability for nuclear catastrophic situation, few parts for high reliability and circuit's understandability.

The reset button does feel "energized" to the touch, this I noticed.

EDIT: as for the experiment, so far the magnitude of the periodic component of the signal seems largely unchanged. What's interesting is that short-term variations in background GM readings seem to track to some extent those also present in solar B-flux data. However, it could be just an impression (or wishful thinking).

Solar B flux data here:

https://satdat.ngdc.noaa.gov/s…/full/2018/10/goes15/csv/

https://satdat.ngdc.noaa.gov/s…/full/2018/11/goes15/csv/ (soon here too)

EDIT2: what's even more interesting is that those short-term variations in solar B-flux data occurred almost 40 hours earlier. To make it align with my Geiger data, I'm shifting it forward in time. This means that daily solar data would have some predictive power on the behavior of the measured background signal. Hopefully I'm not making some mistake somewhere.

This is what I'm seeing on a close-up view of background GM data vs solar flux data. I'm not sure if others can confirm too.

There's not always a 1:1 correspondence but I think not only the general daily trend is similar (which arguably might be kind of expected from a 24-hour periodic signal), but also features on a shorter scale are.

I did a different test today.

1. 2018-11-01 15:35 CET: Finished mounting rig on a movable "cart" in the middle of Room B
2. 2018-11-01 15:46 CET: Moved cart just outside of Room B in front of a thick divisory wall
3. 2018-11-01 16:17 CET: Moved cart inside Room A in front of thick perimeter wall and side of window
4. 2018-11-01 16:33 CET: Moved cart below desk where experiments have been conducted and in front of thick divisory wall
5. 2018-11-01 16:54 CET: Moved cart inside bathroom on the opposite side of the floor relatively to Room A, in front of thick perimeter wall with ceramic tiles
6. 2018-11-01 17:26 CET: Moved cart inside large Room C in front of 7 cm thick radiator alongside outer thick perimeter wall, next to Room A (thick divisory wall between both rooms).
7. 2018-11-01 17:53 CET: Moved cart in front of glass pane of large door-window of Room C
8. 2018-11-01 18:28 CET: Moved cart back in the middle of Room B

magicsound

Thanks. A solar activity signal is still very difficult to see in the data. To make any possible signal clearer, I used a 4-hours average CPM calculation. I tried superimposing scaled/shifted solar B-flux data, using the same offset I use with my graphs, minus roughly 8 hours (the time zone difference, with some wiggle room for the long moving average). Several short-term peak sequences curiously look similar but the long term daily changes do not seem to.

magicsound

I pushed solar data back to take into account that your location would see solar emissions earlier but I forgot to consider the timezone of your data. However since your data has CET timestamps while mine uses UTC, everything more or less correctly aligned as intended.

After testing at different locations yesterday I left the "cart" at a corner of Room A but facing the door of the room instead of the wall (second vertical dashed line in the graph). I think I'll keep it there and let it record the background for a few more days. The photo is showing it just outside of Room B.

The general trend and smaller features still seem to track solar data.

I forgot to mention yesterday that the wall where I recorded the highest signal was one which has had a slightly damp (recently used) bathrobe in front of it for a while, but that could be coincidental. The bathrobe itself, tested in a separate location away from walls, didn't seem to cause an elevated signal.

I took the GM counter for outside testing to make sure it works correctly. I think it does.

EDIT: it might be worth pointing out that for the GM counter DIY enclosure I used cardboard paper that was inside Room A, and the room shows elevated radiation. So there's the possibility of contaminated dust causing briefly elevated readings following wind gusts, etc.

Bruce__H

I do have some of those static-free bags, but not transparent/clear enough for the GC display to be properly photographed under difficult conditions. In any case, I never got such low values here in my premises, so that should hopefully clear questions on whether the GM tube is functioning properly, regardless of measurement oscillations it might possibly have on its own.

I'm still trying to determine if I live in a naturally slightly more radioactive environment than average (a few times over background) or if somehow my testing produced radioactive product of some sort which apparently affects humidity-collecting spots more than others. Fun in a way, but not so fun in others. It doesn't seem like it's Radon, or readings would more quickly change with environmental conditions, ventilation, etc. Or wouldn't they?

Below are attached the data for the above graph, from photos I took at various intervals, in addition to a different version of the same graph with annotations.

Alan Smith

I did a 6 minutes test with a 1.8 kW hair drier blown towards the general area of the setup, but couldn't get readings to oscillate visibly more than they usually do. Possibly they increased slightly, but there was a substantial temperature increase over the previous baseline. The metal parts (screws on the corners) of the GC10 counter were getting moderately warm. What kind of relationship to you usually observe with temperature?

Alan Smith

Understood. Since normally I'm getting the highest readings in the early morning/late night I guess that would rule out temperature effects driving the periodic changes I've observed so far under relatively stable temperature conditions. Speaking of which, I tried plotting the latest 9 hours or so of data and the short-term changes in solar B-flux (from about 39 hours earlier - I've adjusted this slightly over the previous graphs. I don't know about what to make of this delay) here do really look similar in behavior to those in Geiger counter readings.