Radiation Monitoring
Radiation Monitoring for the Coos Bay & North Bend area of Oregon
<viewster -at- charter dot net> (you'll need to compose that into a proper address)
(No: counter, "frames", Java/scripts!, bugs, ads, pop-ups, embedded BS, etc.)

Go to Space Weather for current solar/storm news, Energy News for the latest news about nuclear events and energy alternatives.

Go to  http://radviews.com/map/ (and click the Oregon coast dot) to get my graphs since July of 2014
updated: September 22, 2014
>>fast find>> Air Sampling, Solar Flares, Graphs, CPM, Food testing note, graphing 1-2,
About, G-M tube failure,

You're at: http://webpages.charter.net/123goto/map.htm

** Until recently, I'd assumed that my readings were mostly about "NORM" --naturally occurring radioactive elements/isotopes in the ground or the many types of sands along our ocean beaches --which I supplemented with occasional one-shot air filter readings (and gamma spectrometry for suspicious filters --as available).

** However, I've become persuaded  (at least until someone gets back to me and changes my perceptions) that I've been largely counting "muons": those secondaries which reach the Earth from the steady rain of cosmic rays.


* With reference to my 40+ months of monitoring --now being logged and graphed at:

> http://radviews.com/map/ (click the Oregon dot)

--you'll start seeing a second string of unconnected dots/circles representing another Geiger counter with about an inch worth of lead around it..

The old blue line graph remains unchanged --representing a Geiger counter in an outside shelter in middle of our yard, a meter high and desiccated.

Both run and average for 12 hours at a stretch, but only the outside one is logged and reported each minute (via Radiation Network).

* No reasonable amount of shielding will stop muons. Presumably, that's because at 200 times the weight of electrons, they give grief, rather than come to grief.

> http://cosmic.lbl.gov/SKliewer/Cosmic_Rays/Muons.htm

* Their electrical charge and mass not withstanding, health-physics sources weight muons (any energy level) at "1" --the same as for beta and gamma radiation. I hope they've got their ducks in a row on that. Muons are said to be coming down at the rate of one per square centimeter per minute.

* Interestingly: our Geiger counters appear to count muons at near 100% efficiency --which is my inference, since an LND-7317 G-M tube exposes about 20 square centimeters of cross-section, and that's about as many CPM it logs, even with thick lead and aluminum shielding.

* By contrast: Geiger-Mueller tubes only respond to about 2% of the gamma passing though ---

* --But the dose rate scale (uSv/hr or uR/hr) takes that into consideration.

* Aye --and there's the rub. Whatever is the actual muon component of low level background radiation (at, say: an indicated "0.10 uSv/hr"), the muon clicks (starting to look like 50% or more of the total) are being rated about 50 times higher than they should be in terms of uR/hr or uSv/hr dose units.

Thought Examples:

* Background radiation is being monitored with (say) a beta shielded LND-7317 G-M tube at (say) an averaged 35cpm, 22 of
which are muons. The dose scale would of course be meaningless --unless we kept another Geiger counter running in a well shielded containment (better than what I've got), such that we had a fair idea what the muon component is --with which to off-set the indicated gamma dose units accordingly.

* If the above exampled average increased to (say) 40cpm --a 14% increase in *clicks*, and the shielded muon check unit remained steady, we could then log a corrected 39% increase in gamma.

** This muon stuff amounts to much more than idle curiosity. The issues involved deserve better informed and better equipped attention than I can bring to bear. The truth of the matter will certainly affect the perceptions of our amateur monitoring community --and it might end up skewing some professional/academic low radiation studies as well.

It could be that, even after an atmospheric or oceanic plume arrives, it would barely budge my Geiger counter readings --but best I continue with this long effort.

9/22/2014: * While I'll post no more graphs here, I think it best to postpone this page's departure from Charter.net until the issue of whether or not the Geiger-Mueller tubes in our counters have a significant noise component (see above). "Vital-1" (nom-de-net at EneNews) has pointed out to me that most G-M tubes list a "background" noise. A Chinese model (M4011) calls it "Own Background", at 12cpm, which is on par with normal (or what we've been taking to be), low levels of natural background radiation. The big "SBM-19" G-M tube's specifications indicate an "inherent counter background" of 1.83 pulses per second --which would be 110cpm --SHEESH!

* My impression is that either these Chinese and old Soviet G-M tubes are themselves radioactive (as implied --but I don't think so), or those who sell them simply don't know about the rain of muons we all have to cope with.

I'd like to know for sure if I've spent the last 40 months graphing a lot of meaningless noise from  inside my Geiger counters --and/or from outer space.


** Our monthly cable bill (Internet only, but with this free web space) through Charter Communications has increased to $54.99/month, so I'll soon finish posting here. Save a copy to your hard drive if you want, since I'll be taking them all my pages down before I leave Charter.

We'll either be cadging Internet access off of our public libraries' computers (using a Gmail e-address) or getting another Internet access account with a 3G/4G company.

* Again: I've already begun posting my radiation data to: http://radviews.com, which allows images of my monthly graphs as well.

7/31/2014: * Completed the July graph.

7/23/2014: * The Sun remains quiet --thankfully.

7/23/2014: * Surveyed 5600 square feet of the nearest edge of our sand dune, plus 20 sq-ft of an ash pile someone had dumped on it, at about 6 inches off the ground. I detected no anomalies (by ear).

7/07/2014: * Added beach radiation counts.

7/01/2014: * The Sun has been mostly quiet for weeks now, but a rather large sunspot is rolling around to face us.

6/11/2014: * AR2087 released another X flare, but only of 1.0 strength --and still far from facing the Earth. It was of short duration, but it does have an Earth-bound component. It turns out that the previous two flares also have an Earth-bound component --soon to arrive.

6/10/2014: * A double X class solar flare today: an X2.2 at 11:42 UT/GMT, an X1.5 at 12:52 UT/GMT (04:42 and 05:52 PDT) from sunspot AR2087! Thankfully, these were not from AR2080/2085 --the Earth facing sunspots we've been worried about. I saw nothing in the NETC graphs for 2 private and 2 RadNet monitoring stations which corresponded to these times --despite a wave of ionization which enveloped the upper atmosphere.
* I did a 40 cubic meter air draw today. Although the initial filter activity was unusually low (only 70% over background), that level only decayed by 40% at 40 minutes. (6/11 update: After 24 hours there were no beta/gamma residuals --filter was at background level.)

6/9/2014: * Updated the June graph, adding beach readings (nearly the same as last month).

6/7/2014: * I've not been paying close attention. Although the Sun has been quiet --sunspot/flare-wise, there was a spotless filament which exploded on the 4th, the CME from which has already delivered a "glancing" blow to the Earth.
* A larger sunspot: AR2080, has developed X-class energy and is now coming around at the greatest point of risk to the Earth. So far this cycle, we've managed to dodge the bullet from all such threats. Again: if we can get past this period, the Earth is likely to be safe for a long while --judging from past patterns.

6/1/2014: * Completed the May graph.
* The Sun continues to be quiet.

5/24/2014: * After this date, will comment on one minute CPM counts which exceed 32cpm --instead of 31cpm (to match my GeigerGraph alarm setting of 33cpm).
* Sun continues to be quiet.

5/19/2014: * Space Weather posted good news and bad. We appear to be at the top of what's turned out to be one of the weakest solar cycles (ie: few sun spots and flares) --but some of the worst solar flares and CMEs have occurred on the downside of such cycles. If we make it through unscathed this time, past patterns indicate that decades of quiet sunshine lay ahead. We keep our fingers crossed.

5/15/2014: * Updated the most recent air draw entry.

5/10/2014: * I recently cleaned out and checked our vacuum cleaner's bag (a fine old Hoover upright), as well as the air filter on our lawnmower (a good Craftsman rotary). Moving an RD1503 slowly across the collected debris at about 1/2 inch distance, I could hear no change in the average rate of clicks/chirps.
* You may have noticed that all of my 2014 graphs since "January -b" average something less than 100% of background. That's because I determined my long term (week long) average in January, and January levels tend to be higher most everywhere in the United States. I became aware of that only yesterday as I reviewed NETC's graphed data for several EPA-RadNet stations.

5/9/2014: * A significant number of strong sun spots have formed and are turning toward us.

5/7/2014: * Sunspot AR2051, which has been threatening Earth, erupted with an M1 flare has it rotates around out of view --about a day too late to do us harm.
* The news items at Energy News --some belatedly released (see 4/28 below), has been dreadful. With respect to revelations about the dispersal of "hot particles" (aka: "fuel fleas" from the core of exploded reactors at Fukushima, Japan), I've been unable to identify any such particles here, using my equipment and methods.

5/5/2014: * Added back my test well details.
* There was an isolated 33cpm one minute spike at 17:40 hours PDT.

4/28/2014: * Finally: a report on Oregon fish flesh. See *here* and *here* --only 2 years old --!

4/25/2014: * There was an X1.3 solar flare on April 25th at 00:32 hours UT/GMT. It caused a short wave radio blackout, but since it occurred at the far edge of the Sun (relative to our view of it), this flare's CME will quite miss us.

4/19: * There was an M7 solar flare on the 18th at 13:07 hours UT/GMT --which should only graze the Earth.

4/17/2014: * No more than M-1 solar flares the past week.

4/14/2014: * Read and graphed background at the two beach stations.

4/12/2014: * We've been enjoying a rather quiet Sun for the past week.

4/4/2014: * Started the April graph.

3/31/2014: * completed the March graph.
* Noted: As my graph indicates, the average CPM took a significant leap of 4.7% today (about 4.7 "sigma") above the recent averages.

3/30/2014: *Noted: there was a brief and unusual X-1 solar flare at 17:52 UT/GMT from spot AR1890 on the 29th (UT). That would have been 10:52 hours (AM) local time (PDT). Its CME will only deliver a "glancing" blow to the Earth: (a geomagnetic disturbance on April 1st. What made the flare unusual was that it immediately ruffled the Earth's magnetic field. Unfortunately, I stupidly lost my own data from other Radiation Network stations for the 29th (but I'll blame it on our dog Sammy), so I've put out a request to Radiation Network's station keepers to check their data. My own minute-by-minute CPMs log show nothing special, nor did anything stand out when I checked the graphs for 6 west coast NETC stations.

3/29/2014: * Updated the March graph

3/27/2014: * Correction (below).

3/25/2014: * Made yet another change in the graphing standard by averaging only those morning to late PM hours when my computer is normally running.
* An hours-long, but otherwise modest "C" class solar flare on the 23rd will result in a modest geomagnetic storm today.

3/22/2014: * There was an M1 flare on the 20th and the Sun has once again become mildly active.

3/19/2014: * The Sun has been quiet --despite having a number of spots. However, it's recently been determined that we narrowly missed being hit by a Carrington level event on 7/23/2012 --per the 3/20/2014 edition of Space Weather. The consequences would have been as described here.

3/15/2014: * The Sun spots, one of which (AR2002) was very large, have mostly faded. AR1996 produced an M9 flare on the 12th (nearly an X1), but it was facing well away from Earth at the time. The current worry are two very long magnetic filaments, which appear like rifts across portions of the Sun. These have been known to produce extremely large flares when they collapse. Let's hope our luck holds.

3/9/2014: * The Sun has undergone several M-1 and C class flares --minor stuff.
*(3/27/2014 correction) Goodness: this entry's taking on a life of its own.
Sorry --and special apologies to anyone who's already quoted me. /  If there's anything I hate more than being wrong, it's having to retrace my Internet steps and make amends.  /  Of course I can't give 100% assurance that I was indeed wrong, but it does seem likely --that the EPA limit for cesium-137 has been set at 200 pCi/Liter for some while now --not 3 pCi/L, and per this (referenced in 2011) list, which was commented on at: http://www.nuc.berkeley.edu/node/5874

It's my guess that Jeff McMahon will stand by his reportage/blogage at the lower figure, and I can sympathize with that. This stuff is devilishly hard to find and to understand. However I quite agree with Jeff that the new "PAGs" are a caution.

Craig (who knows little for sure here --other than the *click* - *click* - *click*.)

3/6/2014: * Update to the Solar Flare section.
* I'll periodically fill in the days between 24-hour averages with isolated dots for 12-hour daytime averages on the new graphs.

3/1/2014: * Started the March graph.

3/1/2014: * Starting this month, the aim point will be to conduct 24 hour averaging on the 1st,  3rd, 7th, 14th, 21st, 28th and final day of the month. The first post should occur on the 3rd or 4th day. If we start getting significant spikes or elevated background levels, more frequent averages or a return to 24/7 averaging will result.

2/28/2014: * Completed the February graph,

2/25/2014: * We dodged the bullet --once again. At 00:49 UTC (16:49 PST on 2/24), sunspot AR1990 (which, I gather, is the 2nd time around now for old AR1967) --belched out a powerful X4.9 flare, but almost 90 degrees away from the Earth.

2/22/2014: * Did an air filter draw.
* Checked the two beach stations.

2/20/2014: * The Earth is being buffeted by a series of minor to medium CMEs from a series of mostly C-class solar flares.

2/16/2014: * The Sun is relatively quiet --and that solar storm didn't materialize.

2/14/2014: * In recent days there's been a series of medium solar flares a C and low M class (M-2 earlier today). Two of 3 closely spaced CMEs will arrive almost simultaneously on the 15th with a good chance of polar solar storms.

2/5/2014: * AR1967 appears to have coughed up no more than an M5 flare since January and is now turning away from us.

2/1/2014: * Corrected the new January graph's percentages line to the new (last week in January) average of 15.77. Recently, it was set at 15.99, based on 20 days of spaced hours, through January 28th. Before that it was tentatively set at 16.10cpm, buy direct comparison with an SBM-20 G-M tube instrument and earlier LND-7317 G-M tube based logs. That last week swings a bit, but not unlike the range of earlier weeks. The important thing is to pick a number and stay with it, or else trouble to reach back and correct all earlier logged percentage or "sigma" values to any newly determined base line/average --which I've just done.

1/31/2014: * Sunspot AR1967 continues to be active, with an M1 flare and CME earlier today.

1/30/2014: * The Sun released an M6 level flare and CME today at 16:17 hours UTC/GMT --from the monster sunspot "AR1967". This less than "X" class, but still strong flare occurred with AR1967 facing well away from Earth.
* I wasn't satisfied with the graphing modes I've tried, so I've gone to day averaging --which, by being more inclusive, should be less susceptible to statistical artifacts. The graph will now account for nearly 24 hours out of the day --instead of 5 hours distributed throughout the day. I'll continue watching for and noting any unusual short term spikes at my station. Unless grouped, isolated spikes of less than 4 standard deviations/"sigmas" will be ignored, since 3 sigma counts occur several times per day --by statistical probability alone. At a station average of 16cpm, a 4 sigma spike would come in at 32cpm (by my calculation).

1/17/2014: * Reduction of this page is fairly complete. The last (1/15/2014) edition of the original verbose page is available upon request --as an email attachment.


My Background Radiation Graphs

March-April 2011 (Note: 10 uR/hr = 35cpm with the new Geiger counter)
22nd: That peak is probably no more significant than the next, since I was only taking 2.7 minute counts (+/- 7.2cpm or +/- 2uR),
going to 10.7 minutes on the 24th (+/-3.6cpm). (I'm using twice the "standard error", based on the square root of the total count.)

April-May 2011

May-June 2011 (Note: 10 uR/hr = 35cpm with the new Geiger counter)

June-July 2011

August 2011 (Note: 10 uR/hr = 35cpm with the new Geiger counter)

September 2011

October 2011 (Note: 10 uR/hr = 35cpm with the new Geiger counter)

November 2012

December 2011 (Note: 10 uR/hr = 35cpm with the new Geiger counter)

January 2012

February 2012 (Note: 10 uR/hr = 35cpm with the new Geiger counter)

March 2012

April 2012 (10 uR/hr = 35cpm with the new Medcom Geiger counter)

May 2012
The graphs beyond this point change scale and are primarily calibrated in (Medcom "Inspector") CPM,
sometimes with supplemental uR/hr equivalents on the right margin. (10 uR/hr = 35cpm with the new Medcom Geiger counter)

June 2012 (Note: 10 uR/hr = 35cpm with the new Geiger counter)

July 2012

August 2012

September 2012
* That increase in variation after the 11th is due to reducing the averaging period from hours to 100 minutes. We expect +/-0.6cpm of jiggle at this level of detection and averaging of "Poisson distributed" radiation data.

October 2012

November 2012

December 2012

January 2013
23rd: Confirmed high BG with 2 extra mid-day 100min counts;  26th:  +24.5/14.4cpm mid-day AFs. (Mid-day 10min BGs of 38 & 41.2cpm.)

February 2013

March 2013

April 2013

May 2013

June 2013

July 2013

August 2013

1st: * See my notes about elevation tests with a Geiger counter.

26th: * Those large dots are 100 minute averaged readings made with my "Inspector" Geiger counter (sealed inside a thin "ZipLoc" plastic bag). Note that the last dot is double, the lower blue dot being the count with beta radiation blocked. The smaller black dots are 26.66 minute Radex RD-1503 (SBM-20) averages, taken over a period of about 30 minutes, expressed in "Inspector" (LND-7317) nominally "equivalent" (for gamma) CPMs, for which totals, the standard error is +/-2.6cpm.

* It appears that the large black dot, 5-day whoop-de-do on this graph is all about beta radiation --the stuff I wait for to go away before testing my air filters for residuals. There was no rain until until the 25th, so the invasive beta (radon daughters, presumably) might have been driven out of all the sand around here by our sunny warm days of late. (The 26th was especially warm, but also windy and dry.)

* On the 25th I ran inside and outside tests which included using my old Radex-RD1503 Geiger counter.  Like in the past, I saw no increase when I took it outside (actually getting a slightly lower reading), whereas the Inspector, with its mica window, reads about 11% higher in the same location. This is most likely because the RD1503 is less sensitive to beta radiation.

* It started raining again while I was running the outside RD-1503 count, but there was no effect upon the last 5 readings^. Nor did the rain and steady drizzle of the 25th seem to affect the "Inspector's" readings.

^ The RD-1503 has neither a long count timer nor a data port, so I have to take a reading every 3 minutes in order to build up a longer average --than I can get from its native 160 second cycle. However, it still seems stable and in calibration, so I'll use it for my outside counts. (The exercise will do me good :-)) My purpose in this is to possibly get an earlier warning, should fall-out or volatilized gamma emitters from the beach begin accumulating. (We're fairly close to the bay and Pacific ocean.)

* Note that the last big dot is double. The lower blue one is the Inspector's average with beta blocked. Laying the beta blocked "Inspector" Geiger counter on the ground gave nearly the same reading: 36.33cpm. Removing the beta shield ran it up to 44.37cpm (off the chart, but that's mild, compared to some of the beta CPMs we read about elsewhere after "rain-outs" (or "rain-ups" --not sure).

* Having reverted to placing my old Radex-RD1503 Geiger counter out in the yard (34 inches above ground) for a 26.66 minute averaged count, I'm multiplying the indicated "uR/hr" by 3.5 for a rough "Inspector" Geiger counter equivalent.

* I deal with our radon CPMs to some extent when I do air filter readings, recording the initial value and their signature rate of decay.

28th: * No Radex outside check (small dot) today.

29th: * I ran outside Radex Geiger counter (SBM-20 tube) outside check twice, once open, again with 1/8" aluminum shielding: no difference --but that was anticipated, since past outside versus inside Radex checks showed very little difference. After a series of bench tests with potassium chloride and varying aluminum shielding, it appears that the Radex behaves as if it has about .009" of aluminum shielding (over an imaginary mica window). The impression I get is of very weak (under 100KeV) beta at 34 inches off the ground --which changes my gnotion of what "half value layer" (HVL) means with respect to beta. I thought that the intensity of beta electrons was only "depopulated" to 50% by an HVL (at whatever associated KeV), but that the energies of the remnant beta stayed the same. (Obviously, gamma behaves on the depopulation model, since passing light through a 0.3d (50%) neutral density filter does not change its color, and since useful gamma spectrometry can be performed on the radiation escaping (say) the large cadaver of an ocean creature, or the living body of a "nuclear medicine"/imaging patient.)

September 2013a

1st: * No Radex readings today.

September - 2013b

* 8th: Added this 2nd September graph, based on SBM-20 Geiger-Mueller tube sensitivity --after the LND-7317 G-M tube in my Medcom "Inspector" Geiger counter failed. An SBM-20 runs at 15cpm in a 10uR/hr gamma field (from Cs-137), while an LND-1317 runs at 35cpm.
* 13th: A stray cat delivered 5 kittens under our deck, which has been taking up a lot of time --getting them in, taming, arranging for spay/neuter and adoption --so: my readings are down to little more than once per day for a while.
* Please note that with the smaller tube and shorter (cumulative) counting period, I've more than doubled the "noise"/jaggedness of my graphing. The "standard deviation" is +/-0.9cpm (or let's say: +/-1cpm --at an average of 15cpm) --and it shows.

October - 2013

A map of our two field stations, our fixed outdoor Geiger counter and our portable Geiger counter

*5th: Was able to install a Russian SBM-20 G-M tube in my failed Medcom "Inspector" Geiger counter. I've got about 43% of the Inspector's original gamma sensitivity, plus I've lost the ability to detect alpha and soft beta radiation --but I can once again do automatically timed counts plus participate on-line with Radiation Network.
*9th: We selected two remote locations for 30 minute monitoring counts: 4.7 miles in from the mouth of Coos Bay (EBR = Empire Boat Ramp) and two miles south of the mouth (SB = Sunset Bay). We'll check these high tide spots throughout the year.
*27th: Resumed doing periodic air filter monitoring, but drawing about 4.4 cubic meters of air over 15 minutes --instead of the old 10 cubic meter standard. The buildups in the filters were weak, with 50% more CPMs (at about  2x background) in the draw taken 2 inches off the ground, than in the filter drawn at 12 feet above ground level. Of necessity, only a 10 minute initial reading, then another 40 minutes later, were taken. Consequently, the possible errors were large, but the decays were: to 69% (2 inch high draw) and to 43% (12 foot high draw) over 40 minutes.
*28th: Tested the two air filters of the 27th, finding their gamma and hard beta radiation to be indistinguishable from the background level.

November - 2013

*EBR, SB and Home: see note on the October graph.
*28th: Ran an air filter draw, finding the initial CPMs reading clearly at 4.5x background in the test jig. The decay rate (to 73% at 20 minutes) had a radon daughter profile. The filter read at background, 24 hours later.

December - 2013

5th: * Began monitoring with the new outdoor station.
11th: * Began 60 minute counts at home (30 minutes at remote Empire Boat Ramp and Sunset Beach stations).
16th: * Began 24/7 air sampling at low velocity (1.36 cubic meter/day, instead of sporadic draws of 4.4 cubic meters in 15 minutes).
19th: * With the approach of winter storms and continuous air sampling, the intake was lowered to 9.6 feet above the ground.
20th: * Have both a beach sand sample and 3 air filters (1st low velocity and 2 old filters) on their way for gamma spectrometry.
24th: * The new outside monitoring station seems stable. Will begin running it continuously on-line with Radiation Network.
26th: * Stopped 24/7 air sampling. Filter was soaked from condensation.
* EBR and SB: see note on the October graph.

I keep an eye on the daily, minute-by-minute (Radiation Network) "GeigerGraph", which looks like this:

* That isolated spike at 5:39am is a standout, but it wouldn't have shown up on my graphs.
* I have a problem with GeigerGraph's "3D" display, 1 minute counts, unco-ordinated dingbat time base intervals, red against memory hungry gradient electric blue, and the smushed up lack of resolution. GeigerGraph versions 5.x, now in beta release, will do a lot better.

January - 2014a

January - 2014b

11th: * I'm not satisfied with any of the graphing modes I've tried (and see below).
22nd: * Did two 65 minute (19.1 cubic meter) filtered air draws today, getting unusually high initial radon/daughter readings (9x and 12x background) which decayed to 51% and 50% in 40 minutes (gamma and hard beta only). They'll be examined with gamma spectrometry.
26th: * Air filter update. The 9x filter checked out as having no residuals. (Thanks, Tom.) We're still waiting for a report on the 12x filter. (2/22: I never did get a final analysis on the 12x, but the preliminary graph implied that the lab (not Tom's) didn't have enough substance on the filter to get readings sufficiently above background.  I thank both labs for having a go at my air filters and I'll be quadrupling my air draws.)
29th: * I'll be going from 1 inch to 2 inch diameter air filters here. I get about the same volume rate (limited pumping and plumbing capacity) but the flow rate per square inch will be 25% as much (better?) and the filter size is a better match to a 2" scintillator crystal.
30th: * There was no evidence of the M6 solar flare today at 08:17 PST (16:17 UTC/GMT) in my minute-by-minute counts. However, there was an isolated, 1 minute, greater than 4 sigma of 33cpm at 07:35 today.
I'll continue watching for and noting any unusual short term spikes at my station. Unless grouped, isolated spikes of less than 4 standard deviations/"sigmas" will be ignored, since 3 sigma counts occur several times per day --by statistical probability alone. At a station average of 16cpm, a 4 sigma spike would come in at 32cpm (by my calculation).

February - 2014

* Days during which my minute-by-minute CPMs reached 33cpm or higher: 2/1 (33), 2/12 (33), 2/13 (33), 2/14 (34), 2/16 (33).
22nd: * We had two dry sunny days in a row, so I checked the beach stations and did a 40 cubic meter air draw, getting what's apparently radon/daughters (40 minute half-life) with an initial reading of 5x background.
23rd: * After 39 hours, the air filter read at a normal background level.  I'm sending this filter to Tom's lab for gamma spectrometry.

March - 2014

2nd: * Began adding 12 hour daytime though evening averages as unconnected small black dots. (Might not catch every day's count.)
13th: * An isolated single minute count of 33 at 21:42 hours.
20th: * An isolated single minute count of 33 at 11:19 hours.
22nd: * Gave up on 24 hour averages (as being not much different than 12 hours) and went to all 12 hour --and all connected on the graph.
28th: * Whoops: shut down the computer before I saved my CPM data --but it was running 15-something, per usual. (My dog's fault! :-)

April - 2014

13th: * There was an isolated one minute count of 32 at 20:34 hours PDT. Presumably, this was a random high (re: "Poisson distribution").
14th: * A rather high reading at the Empire Boat Ramp today, but not at Sunset Beach. EBR was higher in February as well.
* "100%" was (arbitrarily) normalized to the last week in January --which appears to have been a few percentage points higher than the annual normal average. I'll stick with it never-the-less.
15th: * There was an isolated one minute count of 33 at 14:17 hours PDT.
16th: * There was an isolated one minute count of 34 at 19:49 hours PDT.
20th: * Whoops: forgot to turn the data logging program on today --sorry.

May - 2014

9th: * There was an isolated 32cpm one minute spike at 23:45 hours PDT.
12th: * Got another high reading at the Empire Boat Ramp today --though not a record, and Sunset Bay was fairly high as well. Both readings were above clearly delineated (by detritus and seaweed) high tide/wave wash lines.
* Again: I originally expected Sunset Bay to be higher, since it opens upon the ocean --particularly as we anticipate the Fukushima plume's arrival. It might be that the Empire Boat Ramp station (4.7 miles up into the outflow of the Coos River) is located on dredgings which happen to be more radioactive. Another possibility is forest run-off, abandoned and current mining operations further up the river.
* I'm torn as to whether I should always station on the same maximum tide line spot, or follow the most recent/apparent high water line as it advances and recedes. If I keep so moving the station, I might cross a vein of thorium rich sand and get a false impression about encountering evidence of the Fukushima plume. What's your opinion?
* I also did an air draw today. It was supposed to be 2 hours (40 cubic meters), but I drifted off to sleep and it ended up being a 140 minute draw (47 cubic meters). The initial N95 filter activity was fairly low (4.4x background) and it decayed at a classical radon daughter rate (to 48% in 40 minutes, counting gamma and beta only). After 49 hours, the filter checked at background, so there were no residuals that I can detect.
16th: * There was an isolated 33cpm one minute spike at 15:06 hours PDT.
18th: * No birds at the feeders this morning --very unusual, but has happened once before. We normally have 15 to 20 pigeons and dozens of chirping small birds (sparrows, blackbirds, cow birds, crows). They must have come later, but not enough of them to scour the bottom of the elevated small bird feeder.
19th: * Up to 15 pigeons trickled in, but initially, no small birds again.
22nd: * There was an isolated 32cpm one minute spike at 09:01 hours PDT. (Will begin noting spikes at 33cpm after this entry.)
24th: * Sorry! I flat forgot to turn the data logging on today.
* Back to normal on pigeons, small birds still somewhat diminished.

June - 2014

05th: * No pigeons, sufficient small birds at the feeder.
06th: * 6 pigeons, sufficient small birds at the feeder.
07th: * 12 pigeons, normal number of small birds.
10th: * Pigeon and small bird count back to normal. (Turns out a family of ferrel cats moved in.)
* Did an air draw today: 40 cubic meters. The initial N95 filter activity was quite low (1.7x background). After 24 hours the filter checked at background, so there were no residuals that I could detect.

July - 2014

10th: * There was an isolated 34cpm one minute spike at 12:02 hours PDT.
12th: * Did our monthly 40 cubic meter air draw --through a small N95 filter. The initial CPM was exceptionally low: 56% above background, which then decayed exceptionally fast --to 15% in 40 minutes --perhaps because my deviation errors ganged up on me this time. (I'll try to get this air draw data onto the above graph, which will be periodically posted to: http://radviews.com.)
27th: * Isolated 34cpm spike at 10:37 hours PDT.

Graphing modes compared

* Using the Open Office spreadsheet (dot org version, which really works well for my purposes here), I was able to make "moving average" graphs --somewhat graphically tortured versions of which you see above and below a segment of the kind of graph (5, spaced out, hour-long, averaged segments out of 24 hours) that I've been posting. These moving averages run through the whole 4 days, incrementing a minute at a time. (After the first minute, the first logged CPM is erased, the 241st CPM is added to the list, the total is added up, then divided by 240 --and so on for 5760 operations.)

* I trust averages and moving averages to better represent data than relying on some sort of spline "best curve fit", "exponential" or "binomial regression" graphing program routine.

The several graphs I've generated all look different --and I don't like any of them ----so I might as well stay with what I've been doing (5 manual operations), despite its tendency to miss events and produce statistical artifacts (dips and peaks).

Again: I'll keep an eye on the daily minute-by-minute graphs, so as not to miss anything egregious.

Here's an illustration of the radon decay chain:
Normally, I filter out the alpha, so those lead-214 and bismuth-214 components meld to give a typical half-life of about 40 minutes (which varies a bit, depending on how long you wait to time it). When I recently read the alpha as well, however, the 40 minute decay went down to 29% of the initial CPM (using a Medcom "Inspector" Geiger counter).
Air Sampling:

* A vacuum cleaner pulls about 8.8 cubic meters in 30 minutes through a 3M brand N95 filter patch.
(Note that 3/8" bypass hole, such that the vacuum motor gets enough air to not over-heat.)
The filter measures 1-3/4" diameter ( 1-1/32" exposed to air flow). At left is the filter unit: a standard 1 inch PVC union fitting. Next is the assembled filter --about to get its weather head. Finally we see the filter/intake as it was originally located high above the porch rain gutter, but now 26 inches (and 115 inches above ground level (measured from the bottom of the weather head) so as to survive our winter storms. (It's thanks to James Hollen for that plastic pipe union idea.) These filters are cut from face masks, so to keep them from humping up in the test well/chamber (imaged just below), I cut them down after the air draw to the exposed diameter.

My test bed's well spaces samples and filters about 1/4 inch from the Geiger counter's screened
window. The stepped aperture 1/8" above the well is for landing that aluminum plate. I can then
subtract beta and alpha from the gross count. (But there's no longer any alpha detection. Despite my
tender loving care, this Inspector's G-M tube failed at 14 months, so I retrofitted it with an SBM-20.)

Checking Food

* It's my guess that food seriously contaminated with a gamma emitting nuclide (say: Cs-137) would test reasonably well with a Geiger counter, but not sufficiently well to prevent the ingestion of just a few scattered particles). Per my own experience with liquids and moist foods, I expect that measuring beta emitting contamination requires either desiccating the food item, mixing reasonably transparent food with a scintillating substance in a blender, or doing something like spectrometry on the incidental gamma radiation involved (which takes honorable equipment).

* To be quite clear: beta radiation is nearly all blocked by the moisture content and bulk of foods. When desiccated and/or thinly sliced, the available beta count goes considerably, but even serious traces of polluting radio nuclides are likely to be swamped by the natural potassium-40 content of many foods.

* Even though Geiger counters are very inefficient at detecting gamma rays (maybe 3% of what passes through), gamma emitters seem (to me) to be the only practical isotopes for an amateur with a Geiger counter to check for. That requires timed counts (at least 10 minutes) of the sample and a background reading (to be subtracted), and an a 1/8 to 1/4 (3mm to 6mm) thick aluminum plate to knock down any beta. (Alpha readings require an unbagged, mica window Geiger counter, very close (1/4") proximity and a paper shield to see if the count goes down significantly.)

* Be very careful not to contaminate your Geiger counter. Bagging it in a ZipLoc is a good idea.

* William Milberry is obviously sincere and gets across the idea the difficulty of capturing sparse radiation in his video, but he should be talking gamma from cesium-137 (actually: from the barium-137 daughter), since we don't see much of the Cs-137 beta decay with a GC --unless the contaminated sample is desiccated and spread thin.


Also: I see that the Green Party (USA) has been opposed to nuclear power plants for years --never having bought into the greenwashing of nuclear energy.

The Solar Flare Threat

3/06/2014 update: *link* (to a 3/4/2014 Wall Street Journal article by Rebecca Smith --which might display in full the first time you access it --but which might subsequently fade out. Apparently, this is the WSJ's new way to game us into subscribing), with more recent information on the availability of replacement EHV transformers. We do have a domestic manufacturer who can build the big ones (400 tons --similar to the largest stones in ancient megalith monuments), but it takes months to complete and deliver one. A recent delivery from an overseas source took about 2 years. (Hat tip to Majia.)

3/15/2013:  Either the 2012-2013 solar maximum will be unexpectedly tepid, or it will come as a delayed "double peak". Watch the video at NASA Science News. Prevailing opinion favors a repeat of the double peaks we've seen in the last 2 solar cycles. (That video also reference a double peak during solar cycle #14 [early 1900s], but I didn't see one in the record that I looked at.)

If we do get a double peak, the second one might have us weathering a series of "X-Class" flares and coronal mass ejections ("CMEs"). Whether one of them smacks the Earth and shuts down some of our power grids is a game of roulette.

It's vital that our political leaders understand and address the following points. (Good luck on getting through to them, but one presidential candidate pledged to phase out nuclear power: Dr. Jill Stein.)

* Nuclear power plants, despite that they might end up literally bursting with thermal energy, are designed such that they're unable to power their own cooling pumps --in the event that there's a local failure of the power grid. On-site diesel-electric backup power then takes over to run the pumps, controls and instrumentation.

* I know that's hard to believe, so rather than simply discounting my concerns here, please confirm it for yourself. Google on "station blackout". Newer designs use steam power to run turbine driven water pumps, but they still require electricity to open valves and turn those pumps on.

* Because the spent fuel pools (SFPs) were only meant to hold 1/4th or 1/8th of what was eventually crammed into them, there was no provision to supply them with emergency backup power.

* To be very clear about this: there has been no provision to connect the diesel backup generators to the SFP's cooling pumps --!! The plan was to simply let the water in the pool coast up --to the boiling point, if needs be (which might take as little as 24 hours), and to then replace boiled off water by means of manually deployed fire hoses.

* The SFPs are crammed with old fuel rod assemblies because there's no place to store nuclear wastes, and because the operator/owners of nuclear power plants are too cheap to use "dry cask storage".

* There are several deadly important things to understand about "spent" fuel pools and rod assemblies:

    ~ Their radioactivity is far more deadly than fresh nuclear fuel rods.

    ~ There's serious question as to whether their 40 year-old liners can stand the strain of boiling water.

    ~ If the zirconium cladding on the fuel rods gets hotter than 1800 degrees Fahrenheit, it oxidizes with steam and water, releasing explosive hydrogen. Above 2000F, the oxidation process turns into a furiously burning fire which destroys the rod, releasing its radioactive contents.

* As to keeping a reactor's containment cool after a shut-down, months of mechanically forced water cooling are required --but the U.S. Nuclear Regulatory Commission has only required that nuclear power plants be independently capable of supplying diesel-electric backup power for 72 hours, plus 4 hours worth of battery backup power --to cover any delay in getting their diesel engines to turn over.

    ~ The Fukushima Daiichi power station reactors had 8 hours of battery backup power. They used every bit of it.

    ~ The NRC might have recently started upgrading that requirement t 8 hours of battery and more on-site diesel fuel. The recent near nuclear disaster at New Jersey's Salem nuclear power plant established that they had a store of 7 days worth of diesel fuel on hand.

    ~ While SFPs might require mechanical/forced cooling for a year, I don't know how long mechanical cooling is required to remove residual heat from a normally shut down, intact reactor in order to maintain "cold shutdown". The damaged reactors in Fukushima have required months of cooling.

    ~ Backup power will continue to be available at a nuclear power plant if more diesel fuel can be delivered to the power plant, if the diesel generators remain operable, and operator personnel can be persuaded to remain at their posts. (The regular Fukushima crew initially fled, but was successfully ordered to return. The head of TEPCo has stated that, in the event of a fuel fire, he'd have no way of ordering his crews to face certain death in order to mitigate the situation.)

* A report by the Oak Ridge National Laboratory stated that over the 40-year licensing term of a nuclear power plant, solar flare activity adds up to a 33 percent chance of it experiencing a long term power loss: a risk significantly greater than that of earthquakes and tsunamis --!

* Federal government studies have suggested that extreme solar flares could result in regional blackouts lasting months or even years, since critical power grid components like EHV (extremely high voltage) transformers are made in places like India and we have scant spares here in the United States. There are more than 300 aging, vulnerable EHV transformers in substations across this nation and the existing over-seas manufacturers of these transformers currently have a 3-year backlog of standing orders.

* A severe solar storm might destroy hundreds of transformers world-wide, leaving vast populations without water, sewers, hospitals, TV/radio broadcasts, fire and basic safety services. Military escorts would have to bring in fuel tankers through the ensuing chaos from our strategic reserves, since the pumps which normally transfer gasoline and diesel fuel wouldn't be operating, nor would refineries be making more.

* I understand that nothing material has been done to provide for the recovery of our power grid.

* As of 1/22/2012, the prediction was for a long, quiet series of solar cycles, following the 2013 maximum. Since our nation has already passed up years of opportunity to prepare for a solar flare disaster, and since it would take about 3 years to prepare if we started now, there are only two meaningful things to be done.

1) Shut down all nuclear power plants (before a solar flare strikes).

2) An executive order which would establish a national emergency force and plan to provide for a year's worth of backup power. Under National Guard protection and execution, helicopter deliveries of stockpiled fuel, replacement diesel generators, and replacement operating and management personnel would be made available to all of our nuclear power plants, once it becomes apparent that blackouts are imminent.

Realistically, this is unlikely to happen before the dangerous 2012-2013 period has passed --unless key government and military officials can be made to think about, and publicly discuss --how dangerous it is to continue operating our nuclear power plants. Let's hope and pray that our luck holds through 2013.

Sources: John Kappenman of Storm Analysis Consultants and Metatech Corporation, as commissioned under Executive Order #13407, NASA Planetary Sciences Director James L. Green (See the February issue of Sky & Telescope), National Research Council Chair Daniel N. Baker (Space Physicist),

> http://www.21stcenturysciencetech.com/Articles_2011/Spring-2011/Power_Grid_Threat.pdf

> http://www.ibtimes.com/articles/194166/20110808/solar-storms-severe-solar-storms-earth-paralyse-carrington-event.htm

About this web page:

* I started it by default of anyone else doing this work for my part of Oregon (which I found hard to believe) --and I still appear to be the only entity, public or private, doing and posting regular monitoring along the Oregon coast. (2014 update: there's a new Radiation Network private station in Florence.) This page use to have links to other radiation monitoring networks, domestic and foreign, which I'm now restoring.

* I no longer make much of an effort to popularize my own monitoring numbers --which (to date, and thankfully) have been pretty steady and mild. I worry about giving people false assurances. Should my numbers go up, I'd worry about spreading false alarms. However, it would be wrong to stop keeping and posting this record.

* Greg's Lab:
> http://www.gregslab.com/tools/radwatch/
Greg's Lab is everything that the EPA's RadNet and other private monitoring networks should be --but often aren't: map based "at a glance" clarity, with the basis of the displayed radiation levels clearly explained. His pages are simple, concise, all aspects freely and publicly accessible. Greg reports the total averaged CPMs (all of RadNet's KeV gamma energy bands added together) for each of the California stations he tracks.

* EnviroReporter:
> http://www.enviroreporter.com/
At Michael Collins' EnviroReporter web site you can easily get at all of the EPA-RadNet station graphs --in their original 9 channel format.

* Radiation Network:
> http://www.radiationnetwork.com/
> http://www.radiationnetwork.com/Message.htm

* At "Message", Mineralab/Radiation Network owner Tim investigates and posts what I consider to be honest and rational reports about unusual readings across his network. (Yes: he has identified what appear to be actual radiation alerts.) Unfortunately, very few alerts are attended to. I understand that a comprehensive "Alert Log" is being developed for a future version of RN.

* Perhaps the strongest feature of RN is its "All Station Average" graph:

--which I'd prefer to see as a single black line (hour averages, say) against a white ground.

* Radiation Network's stations report in "CPM": counts per minute, which makes a lot more sense than uSv/hr or uR/hr when the source is not known. Unfortunately, different Geiger counters have different sensitivities, which RN's map icons and legend attempts to take note of, by distinguishing between high and low sensitivity instruments.

* For presentation on their public (Web page) map, the determination of individual station trends and "Alert" status is being averaged over intervals longer than a minute.

* Radiation Network's current "Alert Level" of 100 CPM seems a good compromise choice, but it will probably be individually adjusted later to accommodate the disparities among their monitoring stations.

* None of the stations are characterized as to what's being counted or how and where those instruments are positioned --but (again), high and low sensitivity stations are identified and their responses are being equalized as to trend status.

* RadNet:
> http://www.epa.gov/radnet/radnet-data/index.html
Not to be confused with "Radiation Network", RadNet is the EPA's no-bid private contractor for keeping tabs on radiation blowing across the United States. It's performance and readiness over the years has been and remains disappointing. RadNet's data is now posted to the public as one-line (all gamma counts totaled) graphs, much as we see them at Greg's site. To get at the original 9 energy channel format, scroll down at EnviroReporter's web site. To see historical RadNet data and current data in context, subscribe to an NETC membership.

> http://netc.com/
It's not clear to me how the "RadCon" levels are determined on the public map, so i tend not to pay them much mind. However, if you've got $20 per year for a paid subscription, network owner Harlan has done an exemplary job of graphing years worth of RadNet's and NETC's own private stations --your choice of averaging and time spans. NETC reaches into Japan as well. Here's an example of the NETC's graphs:

3 Years of (day averaged) beta data for San Bernardino, California (click to enlarge)

* Black Cat Systems:
> http://www.blackcatsystems.com/RadMap/map.html
The main advantages of this private network are equalized monitoring stations which use Black Cat's excellent software and Geiger-Mueller tube sensing units. Black Cat posts no characterizations for its stations --no matter how high they might read, other than the fixed message: "--things are currently normal".

* RadViews:
> http://radviews.com/map/
RadViews is a promising new, potentially global, radiation monitoring network.

* Radioactive@Home:
> http://radioactiveathome.org/map/
Radioactive@Home is an interesting kit and (crowd sourced) BOINC software based, global monitoring network that's based in Poland. I suggest this operation is more about amateur experimentation and radiation as a hobby.

* Radmon.org:
> http://www.radmon.org/
Radmon.org is another global, kit based network with appeal to hobbyists and amateur radiation experimenters.

My Choice of Radiation Units
(revised: 1-17-2014)

* The earliest versions of this page reported Geiger counter ("GC") radiation measurements in terms of indicated "uR/hr" (microREMs per hour, which equals uSv/hr times 100). The use of GC "REM" units (Roentgen equivalent man") is usually invalid, since it's supposed to be about a hypothetical person's received bodily dose from a single, defined, external, isotopic source. My Geiger counters' REM calibrations were only roughly correct for a cesium-137 source, and for other types of radiation --like external alpha radiation, which doesn't even penetrate the skin, it becomes meaningless. In short: a Geiger counter counts alpha, beta, weak and strong gamma as equal *clicks*.

* The alternative of using "CPM" (counts/clicks per minute) is much more honest. Unfortunately, people are using many different GCs which report varying CPMs for the same kind and intensity of radiation. However: they've mostly been factory calibrated to yield similar uR/hr or uSv/hr values for cesium-137 --such that we can at least hope to be in the same ballpark with respect to "background" and other readings --which, like cesium-137 radiation, are largely gamma in nature.

* After buying a Medcom GC with alpha sensitivity, I began logging all of my as "counts", averaged to CPM over longer periods of time (usually: 10 to 100 minutes).

* The average outside and inside office ambient (or "background") readings here usually vary from about 8 to 12 "uR/hr", which was about 36cpm with the Medcom GC, is now logged in the SBM-20 Geiger-Mueller tube equivalent of 15.1cpm, and transmitted to Radiation Network in the M4011 G-M tube equivalent of 16.2cpm. While I changed from doing inside (the house) readings to outside readings, the CPMs have been nearly the same --perhaps with more variation now.

The best policy is to use Geiger counters in the same way at the same monitoring stations: consistency.

Geiger Counter Failure

* The G-M tube (LND-7317) in my Medcom "Inspector" Geiger counter failed. The unit still had high voltage which measured at an indicated 480 volts, using a 40 meg-ohm loading probe. (The unloaded voltage might well be the 500v that the 7317 is rated for.) I can only assume that the brief starting voltage (too brief to see w/o an O-scope?) is in the range of the specified 400v to 425v.

* The Inspector's electronics counted up when I brushed the isolated test probe across the G-M tube anode connection^.

^**^ Caution: Don't have the G-M tube in the circuit when you do this test! As little as 20pF (20 uuF) of external capacitance to circuit ground (like what's between the test leads from your meter), if placed directly across a G-M tube, can destroy it, so if the G-M tube is in the circuit, stand off your test probe with at least a 4.7 meg-ohm resistor at the tip. (I like to use the input resistance of the volt meter for the stand-off resistor --so I can simply double what's displayed. By knowing the combined DC probe impedance of your meter, and knowing the effective source impedance of the circuit you're probing, you can multiply the display voltage by whatever factor is required --should you need to know the unloaded voltage in a high impedance circuit.)

* Unimpressed by the life span of my pancake G-M tube (AND its original 90 day warranty via Medcom --recently (2014) extended to a full year), I replaced it with a Russian SBM-20, which can be had for about $35 ($20 if ordered direct from the old Soviet countries). These are tough, durable puppies with about 43% the gamma sensitivity of an LND-7317, no low energy beta sensitivity, and (of course) no alpha sensitivity at all.

* The operating voltage and the initial voltage had to be reduced to about 400 and 300 respectively. Consequently, I added a high resistance voltage divider consisting of five 10 megohm ("10M") resistors between the original G-M tube anode connection and circuit ground, then tapped off about 380 volts after the first 10M. That first 10M (R1) is bridged with a 15pf (15 uuf) disk capacitor (C1), so that the Inspector's electronics can feel the brief pulses. (This photo will enlarge.)

The following four 10M resistors (R2 through R5) are bridged with two 15pf capacitors (C2 and C5) in series, such that only 2/3rds of the initial supply voltage is felt by the SBM-20 tube.

* This modification resulted in a steady 2ma drain on the 9v battery (18 milliwatts) --for about 23 days of battery life, where I use to get about 3 months per battery. However, I no longer use this GC continuously. Even though the divider string only accounts for only 4.2 milliwatts, one might consider doubling all of the resistors.

It's my guess that this will degrade the high rate performance of the tube, but by using a pulse data cable connection to my PC, the high end already starts rolling off above 5000cpm anyway, and badly above 15,000cpm (compared to Inspector's internal rating as being good to 350,000cpm --with the original G-M tube, of course).

* With an SBM-20, the uR/hr display would of course be way off, but I've only ever used timed CPM totals (since the Inspector's sampling period is only 30 seconds or less for anything else).

* I operated my Medcom Inspector pretty much continuously for the 14 months I got to use it. In an average 36cpm background field of radiation, that works out to 22 million total counts (2.2 x 10^7), whereas the expected G-M tube life is quoted at from 10^9 to 5 x 10^10 total counts --so it failed about 100 years short of the mark.

* References:

> http://www.lndinc.com/products/17/

> http://www.gstube.com/data/2398/

A comment submitted to "EnviroReporter" on 8/7/2014:

Some points:

* I don't operate RadViews, I only post to it --in anticipation of retiring my own web pages later this month.

* While I've learned more about radiation monitoring these past 40 months than I ever cared to know, I'm not by any stretch of the imagination a qualified expert. (It's quite a struggle. Why aren't their more professionals helping us?)

* "100cpm" only has meaning in the context of what's being counted, with what kind of sensor and what the history has been for a given monitoring station.

* EPA-RadNet stations use very sensitive devices to measure the beta radiation from concentrations of dust/air pollution in their filters, whereas amateurs who have a sensitive enough counter to set their alarm at "100" might simply park an affordable Geiger counter on a window sill --and we're then mostly counting gamma.

* I've long wondered at the comings and goings of beta counts, which seem to be 99% about radon daughters (at least for those of us using beta sensitive Geiger counters, air filtering and/or "wipes"). These counts can vary widely and they should concern us, with something like 20,000 radon induced lung cancer deaths per year--!

That being said, it takes a dedicated radon detector in an interior residential space to come up with a meaningful number. I can't relate any particular radon daughter CPM level (which decays by half after about 40 minutes) --even the CPMs from my own air filter runs, to some state or level of concern.

Craig Daniels