Boulder, Colorado ;-), USA – Friday, March 27, 2015
This blog post is mostly data, with some photos and interpretation. (I’m on the edge of rolling my eyes when it comes to data processing, but all this field experience and reference values may come in handy some day.)
The reason I do this is part of an attempt to determine what can and what can’t be concluded from simple Geiger Counter data, to better understand the usefulness ánd limitations of hand-held Geiger Counters so as to be able to use them as best as possible in case of a radiological emergency, and to be discern misinformation (or deliberate disinformation) from quality citizen or official monitoring. And hopefully those who’re interested in this can learn from my findings as well. Comments welcome, but do read my disclaimer first.
Without knowing baselines, I think Geiger Counters are almost useless. So, I’m gathering baselines, basically; or at least data reference points in space and time. Although, post-Fukuhima there’s always thát: in some cases these might be contaminated… can’t tell this way.
I was already very tired before this long transatlantic flight started, so I quit the radiation stuff early on.
The route the plane took was not suitable for gathering comparable data on inside versus outside the jet stream anyhow (at least not at the same altitude and latitude, that is).
Instead of gathering more data about the difference between holding your pancake-sensor Geiger Counter (GC) horizontal versus vertical (I did do one test, see further below, which further confirmed what I found here for my in-flight data, and here for (Herent attic) on-ground data), I choose to gather these additional measurements to check out if I could detect a revealing Beta signal after all, by specifically gathering data with the Beta window on the pillow (no airflow and mostly blocking dust passing by), and some data when holding the GC lifted off the pillow but still horizontal (I did not lift the GC off the pillow until higher up), and this during a part of the plane’s trajectory where the latitude and altitude were relatively stable factors (west of Ireland and south of Iceland). It’s limited data because I got too tired / disinterested. But it is something.
The basic set-up was simply this: Geiger Counter resting on pillow, 1 sheet of note paper, on my lap:
Sidenote: Before I left, I took a couple more Medcom Inspector Alert radiation averages in the Herent attic I live in when in Belgium, with the Geiger Counter horizontal and its Beta window down on a radiation-neutral table:
- 37.5 CPM (24 hr. avg., ending around noon on March 23 – normal, though at the low end of its common fluctuation);
- 41.9 CPM (8hr35min avg., endng 10:30am March 24 – normal, starting to drizzle)
- 42.3 CPM (9hr14min avg., ending 9:50am March 25, rain all night)
- One more vertical, standing on table: 38.8 CPM (2hr40min avg., at 12:40pm March 25, also raining) –> 9.2% difference with horizontal, under otherwise same circumstances, again confirming the findings shared above two links.
- @ Brussels Airport (BRU), a horizontal-vertical mix, some of it with the GC tucked away in bag: only 1276 counts in 48 minutes before take-off => 26.6 CPM (bit low) with dose fluctuation in the range 0.059 µSv/hr to 0.143 µSv/hr (Official FANC data has the average around here around 0.101 µSv/hr, a completely normal background level from mostly cosmic rays and a little bit from natural and man-made soil and airborne radioisotopes. The EURDEP site shows the Belgian data better than the Belgian FANC site, both of which are linked to from my overview page, online worldwide Radiation Monitors.
Turning after take-off just outside Brussels:
Because the data for days without rain and that spike that coincided with rain just before I left showed a difference of some +3 CPM in my data, I had a look at the nearby official monitors, which all show that rain-spike very well. Since the window in the attic remained closed, the uptick is most likely mainly from extra Gamma, not Beta. My Geiger Counter’s +3 CPM (gamma + beta) uptick apparently roughly compares to an 0.011 – 0.013 µSv/hr (gamma) uptick on an offcial FANC/EURDEP monitor. Stuff like that I find “good to know”.
This uptick is within the normal fluctuation range, which can be caused by Berrylium, Carbon, Potassium and other naturally occurring isotopes, as well as by nuclear fallout raining down. It is impossible to discern without lab analysis (or a scintillator at the very least), what part of such an uptick would be due to man-made isotopes from the numerous nuclear power and nuclear medicine facilities in the region. The fine particle pollution in Brussels, just like in London, Salt Lake City, or Milan, sometimes exceeds the infamous air pollution of Beijing, China.
Here’s Gamma radiation graphed for 1 month for Zaventem, Belgium (where the Brussels Airport is): I adjusted the vertical scale to show more detail:
Anyhow… Off to high altitude…
HORIZONTAL – versus – VERTICAL. Couldn’t resist… I did briefly put my GC horizontal versus vertical, but this time in the Counts Per Second (CPS) setting, to triple-check what was already clear from previous tests. Yup: At just above 28,000 feet altitude, I got 11 CPS horizontally (and going as high as 13), versus 8 CPS (sometimes showing 9 CPS) vertically, a 27 % difference (comparing 11 to 8, the most common reading I observed at this part of the trip).
All this is is just more confirmation of the importance of noting this factor in measurements: If the sensor tube is pancake-shaped, how you held your Geiger Counter matters when comparing data. These below shown measurements were taken with waiting 1 minute for the measurement readings to adjust, as you can see in this combination of 2 photos:
Here’s the data from rising to elevation. The first minute or two, the GC may be adjusting to the new counting, not showing a reliable minute-average. On the ascend the measured values are always lagging a bit. It takes less than 15 minutes to rise to 28,000 feet.
24:00 Countdown (CD) = 0 Counts
- 23:59 CD => 21 Counts => (1 min. avg.) -> 21 CPM
- 23:58 CD => 56 Counts => (1 min. avg.) -> 35 CPM
- 23:57 CD => 101 Counts => (1 min. avg.) -> 45 CPM
- 23:56 CD => 143 Counts => (1 min. avg.) -> 42 CPM
- 23:55 CD => 223 Counts => (1 min. avg.) -> 80 CPM
- 23:54 CD => 292 Counts => (1 min. avg.) -> 69 CPM
- 23:53 CD => 393 Counts => (1 min. avg.) -> 101 CPM
- 23:52 CD => 547 Counts => (1 min. avg.) -> 154 CPM
- 23:51 CD => 745 Counts => (1 min. avg.) -> 198 CPM
- 23:50 CD => 992 Counts => (1 min. avg.) -> 247 CPM
- 23:49 CD => 1410 Counts => (1 min. avg.) -> 418 CPM
- 23:48 CD => 1658 Counts => (1 min. avg.) -> 248 CPM
- 23:47 CD => 2019 Counts => (1 min. avg.) -> 361 CPM
- 23:46 CD => 2577 Counts => (1 min. avg.) -> 558 CPM
- 23:45 CD => 3000 Counts => (1 min. avg.) -> 423 CPM
- last 5 minute average: 401.6 CPM
- 23:44 CD => 3477 Counts => (1 min. avg.) ->477 CPM
- 23:43 CD => 3933 Counts => (1 min. avg.) -> 456 CPM
- 23:42 CD => 4417 Counts => (1 min. avg.) -> 484 CPM
- 23:41 CD => 4936 Counts => (1 min. avg.) -> 519 CPM
- 23:40 CD => 5385 Counts => (1 min. avg.) -> 449 CPM
- 5 minute average: 477 CPM
- 23:39 CD => 5851 Counts => (1 min. avg.) -> 466 CPM
- 23:38 CD => 6351 Counts => (1 min. avg.) -> 500 CPM
- 23:37 CD => 6827 Counts => (1 min. avg.) -> 476 CPM
- 23:36 CD => 7317 Counts => (1 min. avg.) -> 490 CPM
- 23:35 CD => 7786 Counts => (1 min. avg.) -> 469 CPM
- 5 minute average: 480.2 CPM
- 23:34 CD => 8277 Counts => (1 min. avg.) -> 491 CPM
- 23:33 CD missed / skipped
- 23:32 CD => 9355 Counts => (2 min. avg.) -> 539 CPM
- 23:31 CD => 9838 Counts => (1 min. avg.) -> 483 CPM
- 23:30 CD => 10380 Counts => (1 min. avg.) -> 542 CPM
- 5 minute average: 518.8 CPM
- 23:29 CD => missed / skipped
- 23:28 CD => 11280 Counts => (2 min. avg.) -> 450 CPM
- 23:27 CD => missed / skipped
- 23:26 CD => 12450 Counts => ( min. avg.) -> 585 CPM
- 23:25 CD => 13000 Counts => ( min. avg.) -> 550 CPM
- 5 minute average: 524 CPM
- 23:20 CD => 16410 Counts => (5 min. avg.) -> 682 CPM
- 5 minute average: 682 CPM
- 23:16 CD => 19200 Counts => (4 min. avg.) -> 697.5 CPM
- 23:15 CD => 19890 Counts => (1 min. avg.) -> 690 CPM
- 5 minute average: 696 CPM
- LIFTED off the pillow with beta window upwards: 23:15 – 23:10 CD => 23510 Counts => (5 min. avg.) -> 724 CPM
- 23:09 CD => missed / skipped (transition after Beta test, back to Beta-blocking)
- 23:08 CD => 25040 Counts => (2 min. avg.) -> 765 CPM
- 23:07 CD => 25570 Counts => (min. avg.) -> 530 CPM
- 23:06 CD => 26300 Counts => (min. avg.) -> 730 CPM
- 23:05 CD => 26990 Counts => ( min. avg.) -> 690 CPM
- 5 minute average: 696 CPM
- 23:04 CD => missed / skipped
- (23:03 CD = “9hrs7min. to destination @ 32,003 ft altitude )
- 23:02 CD => missed / skipped
- 23:01 CD => 29670 Counts => (4 min. avg.) -> 670 CPM
- 23:00 CD => 30350 Counts => (1 min. avg.) -> 680 CPM
- 5 minute average: 672 CPM
- (22:59 CD => 31010 Counts => (1 min. avg.) -> 660 CPM (transition))
- LIFTED off pillow (Beta window not blocked): 22:58 CD => 31720 Counts => (1 min. avg.) -> 710 CPM
- 22:57 CD => missed / skipped (adding extra ventilation air from above vents)
- 22:56 CD => 33140 Counts => (2 min. avg.) -> 710 CPM
- 22:55 CD => 33870 Counts => (1 min. avg.) -> 730 CPM
- 22:54 CD => (transition back to on-pillow at end of this minute)
- 22:53 CD => 35500 Counts => (2 min. avg.) -> 815 CPM
- 6 minute average: 748.3 CPM
- 22:52 CD => 36170 Counts => (1 min. avg.) -> 670 CPM
- 22:51 CD => 36840 Counts => (1 min. avg.) -> 670 CPM
- 22:50 CD => 37460 Counts => (1 min. avg.) -> 620 CPM (“8hrs55 min. to destination”)
- 22:49 CD => 38180 Counts => (1 min. avg.) -> 720 CPM
- 22:48 CD => 38880 Counts => (1 min. avg.) -> 700 CPM
- 5 minute average: 676 CPM
Right after that, I accidentally flipped the switch in the wrong direction and thus turned the countdown back to 24:00 CD … ;-/ I took it as the sign I needed to call it quits. (My note page was full anyhow.) Interesting: the 5 minute periods before and after are clearly less than the 5 (or 6) minute period during which I held the GC just as horizontal, but with the beta window off the pillow exposed to the airplane air:
Beta-Blocked versus Beta-Not-Blocked:
- 696 CPM
- 724 CPM (with Beta window exposed)
- 696 CPM
- before and after average: 696 CPM
- Difference Beta included = + 28 CPM
- 672 CPM
- 748.3 CPM (with Beta window exposed)
- 676 CPM
- before and after average: 674 CPM
- Difference Beta included = + 73.3 CPM
- !-> Average difference Beta Included (2 x 5 min. w/ beta, versus 4 x 5 min Beta blocked): + 50.7 CPM
Speculative: IF the relation between my Geiger Counter’s extra CPMs would be linear (no idea if it is), as well as comparable for Beta and Gamma, then +50 CPM (@ +0.011 µSv/hr gamma roughly corresponding with +3 CPM mostly gamma ), THEN this could translate roughly to a dose rate uptick of + 0.19 µSv/hr of added Beta radiation, from particles in the airplane’s AIR. (???)
Early CONCLUSION: This is very limited data, but it does show that there is elevated Beta radiation in the higher troposphere where planes fly. Whether this is from radioisotopes that naturally occur at this altitude or due to the ongoing releases from Fukushima, or how much of each, can truly only be determined with certainty through precise radioisotope analysis of air filters. I won’t be flying until next winter at the earliest, I think, but that could be worth investigating further. How much it varies from place to place, I have no data for, either. All I did was confirm a significant Beta signal higher up.
My impression is that people who claimed it was nearly ten times as bad (mentioned in Geiger Counter Data from Airplane Flights: DEN -> ATL -> AMS) were thrown off mainly due to the effect of horizontal versus vertical not being accounted for, but that when you take that into account, you’d end up with quite similar findings as what I just found. Then again, although I consider it unlikely, I can’t rule out either that they flew through an area with véry significantly elevated Beta.
A +50 CPM uptick seems significant, but how significant is it due to Beta radiation?
While for sure not per se comparable 1:1 with my data, due to different calibration and sensitivities, I looked at EPA Radnet data for Beta (via https://cdxnode64.epa.gov/radnet-public/query.do), and graphed some examples for Beta for the past week on the coast (Corvalis, OR and Anchorage, AK) and inland (Bakersfield, CA and Albequerque, NM):
Albequerque is not that far (by American standards) from Southern Colorado. Not a bad idea to gather Geiger Counter data right near this Radnet Monitor some day.
–> In any case, as you can see, these vary quite a bit, going as high as +70 CPM on the coast and over +400 CPM inland. Which specific radioisotopes cause these swings, or how much of this is due to man-made nuclear fission, can’t be determined from these data. (Again, that would take lab analysis of air filter samples.)
CONCLUSION: There is a clear elevated Beta radiation signal in high altitude radiation in air inside an airplane, but I have no idea if this is unusual in any way, nor how much this would vary from region to region, nor how much of this can be attributed to man-made causes. For now, this is what it is: just data.
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