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Several months ago (mid-year 2003), I purchased the RM-60 and hooked it up to an old laptop in the basement as a sort of early warning detector in the event of a radiological disaster. I quickly forgot about it in my daily routine.
A while later my father in law suffered a heart attack which got me thinking, maybe I should be tested myself. So the day arrived and all went well. Until I returned home, that is. Pumped full with 35 millicuries of Technetium I pulled in my drive and set off the alarm which is set at 50 micro roetgens/hr.
Obliviously I went into the basement and gasped when I saw the display indicating 58 micro-roentgens/hr ( I have it set so that each column displays one hours average ) the alarm was wailing. The average in my basement is about 21. I've never seen it more than about 30. Puzzled I picked up the RM-60 unit and watched the display jump to more than 8500 micro-roentgens. I felt the adrenaline flow, and I wondered out loud: are we under attack?
Then it occurred to me, the marker you moron. As I held it to my chest the laptop showed an incredible 31549 micro-roentgens. Holy crap, I'm radioactive! I'm very impressed how reliably your product works. It sat down there quietly doing its job until I tooled up the driveway glowing like a lightstick and alarmed before I even got in the door. It has piqued my interest in nuclear science all over again. As I sit here eleven hours later it is sitting on my end table with the LX200 clicking away at 5389 micro-roentgens ( the LX200 is set with 10sec TBU ).
Thanks for an excellent product.
Bryan,
The RM-80 arrived here in good shape and I've made very good use of it.
I have a question for you. Have you ever calibrated one of these for neutrons using a silver foil to catch the neutrons and re-emit a prompt gamma. I would surely like to have some idea of the efficiency of the RM-80 under such circumstances. One recent experiment using the RM-80 and 0.25mm silver foil resulted in a many thousand fold enhancement of counts. I suspect this equates to a huge neutron flux as I cannot imagine the counter efficiency of the GM+Ag is even 1%.
Russ George
Palo Alto
From Randall
Hello
I have been using an RM-60 and your suggested fan arrangement to monitor
radon for many years. It has been instrumental in my efforts to reduce radon
levels in my home. I have found that the radon levels are very much
dependent on the difference between the indoor and outdoor temperature. For
example, I have found a good correlation between radon and outdoor
temperature with the following simple formula:
radon (pc/l) = A x (Indoor Temp - Outdoor Temp) - B
where B is in my case 3 pc/l and the coefficient A has decreased from about
0.6 without remediation to about 0.16 currently with remediation. Using max
and min temperature data from the PA climatologist's web site allows me to
make plots on Excel of measured and expected radon based on temperature as
functions of time.
My calibrations with carbon and alpha track detectors (at least 3 different
calibration runs) have led me to the following conversion from MicroR/hr to pc/l:
radon (pc/l) = (MicroR/hr - 12)x 0.8
The 12 is essentially the average assumed background radiation that I
measured by using the monitor outdoors with no fan. I know the background
radiation varies with time (I have seen numbers between 10 and 13). I assume
it is fairly uniform over large regions of the earth's surface, however.
Does someone measure this and make it available to the public? I would like
to try refining my system by accounting for this variation.
Randall,
Your E-Mail is very interesting. Perhaps somebody will read it on our website and let us know about such a database at which point I'll E-Mail you.
From: Paul.Sawyer@tellabs.com
Subject: My RM-70
Hi,
I recently cleaned the window of my RM-70 - and in doing so
have removed what appeared to be an ink like coating on it ...
Have I broken/de-calibrated it ? What was the function of
the coating, and should I replace it with something -
Thanks,
Paul Sawyer
psawyer@tellabs.com
From: boardmanb@aw-el.com [SMTP:boardmanb@aw-el.com]
To: Sawyer, Paul /bb,its
Subject: Re: My RM-70
Paul,
The coating is graphite powder. It is there to filter out ultraviolet
rays. Once a user did the same thing to his RM-80. He sent it back to
us for re-coating but when I had it here, before re-coating, I held it
in direct sun light with no detection of ultraviolet at all so I would
say your RM-70 is fine without the coating.
(Note for RM users: To clean dust from window use "canned air" from Radio Shack or-the-like normally used to blow dust off lens).
Hey, BTW -
Don't know if you'd be interested in this for your "experiences" page, but the reason I was cleaning it was because I had gotten some dust on it -
The dust came from my water softener - I was using a potassium based salt in it that is supposed to be better for you than the sodium based stuff - I had set my RM-70 near the softener tank and all of a sudden it was reading about 6x background - I came to find out that potassium-40 is radioactive - with a huge half life too. There must be a significant concentration of it in the salt I bought. I informed the Illinois Dept. of Nuclear Safety - they didn't seem to be too concerned, although I did let them know also that a lot of this stuff comes out as dust when you pour the bag into the tank - probably not good to breath.... You can still buy this stuff in the stores - I've got half a mind to take the RM-70 to the store sometime to see what the reading is like around the pallets that they stack it on. I long ago switched back to sodium based softener salt !
Paul Sawyer
A few years back, when I was still living in St. Pierre et Miquelon, I bought a RM 70 with the graphing software. Since 1997 I've been working and living in Newfoundland, employed as an avionics instructor in the local college aircraft maintenance engineering program.
I hadn't used the RM 70 very much recently, but today I decided to take it to work just to see how radioactive the dials were on some of the old aircraft instruments. To my surprise the radiation levels were much higher than I expected, even half a metre or more away from some of the instruments, even though they were inside a closed plastic container, and in one case they were in a closed metal locker. I had only used the earphone adapter for a quick sweep of various locations in the college where these instruments were located.
Ron
I've been using an RM-60 for quite a few years (since the early 90s) in my vacuum lab for monitoring x-ray emissions from various pieces of apparatus and it's been a good investment for safety. It has so far outlasted the ancient laptop that I'd had dedicated to it (no hard drive and I don't think it was even 286 level). It's now running on a salvaged 486.
Steve
I purchased one of your units several years ago and have enjoyed using it. The first time I tried it I was on my way from Melbourne to London and startled my fellow passengers when the alarm on my laptop went off when it intergrated the first data point!
Some data I have measured appears on my home page:
http://www.ph.unimelb.edu.au/~dnj/dnj/buffrad.htm
Assoc. Prof. David N. Jamieson Director:
Microanalytical Research Centre
School of Physics
University of Melbourne
More from Prof. Jamieson:
Many thanks for your fast response. The new software worked fine on my new laptop (after I reclaimed COM1 from the IR port!).
I have attached a radiation profile I took a few years ago of a flight
from Sydney to Melbourne. Notice I turn off the apparatus during takeoff
and landing. But I have never been able to find a satisfactory
explanation for the two intense spikes seen upon boarding and deplaning.
The inverse square law rules out radioactive cargo. I have never seen
them again on other flights. Prof. Jamieson's graph:
Bryan,
Thanks for the info and the update on the MAKDECAY software. I have zipped and attached the file of background radiation data collected from my office. As I mentioned, there is a spike during the holidays when the building was closed. The last scheduled workday of the year was 24-Dec-1997. The building was closed and the ventilation system turned off late that evening. The average measured background increased to a peak on 31-Dec-1997. The ventilation system was started again on 1-Jan-1998 (a holiday) in preparation for a return to work on 2-Jan-1998.
Something else I noted of interest was a daily trend in rising and falling background background radiation levels. First, I used SECTION to extract the data from noon on 27-Oct-1997 to noon on 2-Nov-1998. Then, using AW-Graph, I displayed the data with a compression factor of 360 (equal 6 hours). Zooming in, it was easy to see a daily peak background radiation level occurring generally between 4 and 6 am and a daily minimum about 12 hours later (about 5 to 7 pm). I related this generally to daily usage patterns of the building. This is an observation and a guess. Neither have been tested beyond zooming in on several different parts of the curve and seeing of the pattern holds up.
In the zipped file, I have included a README file that describes my setup. (README follows plot).
19-Jan-1999
This file describes a background radiation data set gathered in the office of Brandon C. Nuttall, Kentucky Geological Survey with an Aware Electronics RM-60 Pro Micro Roentgen Radiation Monitor. The monitor was attached to a laptop PC running Microsoft Windows 3.1 and Microsoft Disk Operating System (MS-DOS) version 5.0. The program AW-MRAD was installed as a TSR using the AW-AUTOT.COM utility at system boot.
The building is a three-story concrete and steel structure with a brick exterior built in 1988. Windows do not open. Ventilation is by forced air. The office is located on the third floor with windows facing approximately northwest.
The monitor was placed inside a plastic ziploc-type bag as a dust protector. Short term experiments (approximately 1 day each) had shown there appeared to be no significant difference between background readings acquired by the unit in or outside of the plastic bag. Monitor and laptop were placed on a table near the middle of the office with the detector window facing the door.
The header from the data file included:
Brandon C. Nuttall, bnuttall@kgs.mm.uky.edu, background in office
Start: Mon Oct 27 09:47:15 1997
End: Mon Nov 02 14:16:15 1998
Total time: Days:371 Hrs:4 Mins:29
Min: 0 microR/hr First-Last: Thu Mar 19 15:40:15 1998--Sun Jul 19 05:51:15 1998
Max: 31 microR/hr First-Last: Sat Nov 01 06:19:15 1997--Sat Nov 01 06:19:15 1997
File's Time Base Unit (TBU): 60 secs. TBUs per point: 1
Average microR/hr: 11.39
Data submitted by:
Brandon C. Nuttall
Kentucky Geological Survey
228 MMRB
University of Kentucky
Lexington, KY 40506-0107
bnuttall@kgs.mm.uky.edu
Hi:
I bought one of your RM-60's a couple of months ago to use on my vacation.
I hooked it to a homemade microcontroller based "computer" and recorded the
radiation levels during the trip as I drove through Texas and New Mexico.
I also stored data from a GPS receiver and thus could see the effects of
altitude etc. At my final destination, I used it to map the radiation
around ground-zero at the Trinity Site where the World's first atomic bomb
was exploded. The unit worked flawlessly and I thought you might like to
see the results. If so, you can go to...
http://www.randomuseless.info/vacation/vacation.html
Phil C. Stuart
stuart@randomuseless.info"
On Saturday I took the new RM-80 to Dinosaur Ridge and tested it on the
radioactive dinosaur bones. The unit responded very well and is very suitable
for my demonstrations. The sound system shows a significant increase in
counts above background. I am therefore pleased.
Sincerely,
Klaus,
The dead time of RM-70 is approx. 80 microseconds. Also see www.aw-el.com/fetch.htm
for "Raw count-rate during decay of 15 mCi of 99mTc. Each point is the average of 10 1-minute acquisitions, without subtraction of background. Marked points represent idealized count-rate values based on extrapolation of the 24 hour measurements. Measured count rate is 5% less than that predicted at the highest count-rates". Given the same count rate, the data should apply to RM-70 as well, although since RM-70 tube is bigger, perhaps its deadtime is a little larger.
Should I place your E-mail on our web site at:
www.aw-el.com/email.htm
with E-mail address?
Dear Bryan,
...
I know that the flux coating of the welding rods is slightly radioactive, so
expected an immediate increase, and this happened. What I was looking
for was a short term decay after the initial rise, indicating that
short-lived radionuclides might have been formed while welding.
This may have happened, but the effect was too small to be seen clearly,
if it happened at all. Saying "what the hell", I left the experiment running
anyway.
A day or two later I checked it and saw to my surprise that the radioactivity
was actually rising! (See attached file WELD01.GIF). The time constant
appears to be 3 - 4 days. Could this be due to due to flux diffusing slowly
out of the weld, or what?
I intend to repeat this experiment, and would be glad if you could suggest
to other users of your instruments that they might try it.
With best wishes, George (Sassoon) geosas@aol.com
I am repeating the experiment of measuring the radioactivity of
a fresh weld in mild steel, and this time I stirred in some salt and
sugar so as to add Na, Cl, C, H and O to the general mess!
I got a slight but real, (I think!) decay over the first few hours, then
it flattened off and is now starting to rise again 24 hours later.
The initial reading this time was higher: 30 uR/hr., background
about 15.
I put a second RM-80 detector underneath the steel strip, the other
side of the weld, alpha window upwards, to see if any radiation came
through the thickness of the steel (about 1/4" - 3/8") but this just seems
to be registering background.
More From George...
This is Greg Shanos from sunny hot & humid Florida. I recently purchased
your RM80 geiger counter. I absolutely love it. I am an amateur astronomer
by passion. I also collect meteorites. The meteorite dealers are currently
selling TRINITITE. This is the fused sand from the first atomic bomb
explosion at the Trinity site in New Mexico. They say it's radioactivity has
all but decayed. Not so. I measured the radioactivity at 314.62 uR/hr (500
data points) The background was 8.13 uR/hr at 500 data points. Is this
dangerous? I have been keeping it under a lead photographers travel bag for
the last few years. I addition, its in the garage.
Can you send me some information regarding roentgen levels that would be
dangerous to your health. I would also appreciate the conversion factors for
Roentgen to curies etc. GShanos@aol.com
Greg, A rule of thumb: One Curie of Radium (1 gram) in equilibrium with
its decay products, at one meter generates one Roentgen per hr. Perhaps,
from time to time, Mme. Curie worked with this much material (possibly
spread out over say a crystallization pan).
I would say, don't breath dust from the TRINITITE and perhaps wash your
hands after handling it.
A stipulation one sees in various regulations, for example in regards to
people working with radioisotopes: no more than an average of 500
microR/hr. for an eight hour work day. For X-ray emission from TVs: no
more than 500 microR/hr. at a distance of 5 cm. from the screen or case.
I thought you might want to know about my success with running your
radiation software AW-SRAD, etc. on an old Toshiba T100X pen computer.
These machines, the size of a textbook or ring binder, were popular
around 1993-94. And they were expensive. Today a few remaining units
are being sold over the Internet for under $200. They have 4 meg of
battery protected RAM, a tiny 40 meg hard drive, two PCMCIA-II card
slots, a serial and a printer port.
They have no floppy drives. An external drive, still available, costs
over $200! Fortunately the computers are loaded with Windows 3.1 for
Pen computing and DOS 6.0. DOS has a utility for linking computers
through either a printer or serial port. So I was able to download your
software to the pen computer, set up PIF files in Windows and run them.
You might say, so what is the big deal? Well, pen computers do not have
keyboards. The Toshiba does have a PS-2 keyboard port. But for
portable use dragging around an accessory keyboard is not attractive.
Fortunately the Windows pen system (actually a large digitizer the size
of the LCD screen) will paste keystrokes into any windowed DOS program.
The T100X has a monochrome VGA screen easily readable in bright daylight
without the backlight on. So for under $200 I now have a data logger
and portable power source for my RM-70 among other things. And it can
run a web browser or email client too, albeit slowly.
Dear Bryan,
This is an interesting experiment you could suggest to your
environmentally-concerned users of AW-EL equipment:
Recently we had a hurricane here in W. Scotland and a lot of
seaweed was washed up. I collected some stems of the
type known as 'tangle' locally, Latin name Laminaria I think,
which has long stems with a bunch of green-brown fronds at
the end, a bit like a palm-tree. I trimmed the fronds off and
left the stems outside in the rain to wash the worst of the salt
off for a few hours. They are several feet long, with a bunch of
knotted roots where they attach themselves to the rocks.
I propped one of the stems up in the kitchen alongside the
Aga cooker, with a RM-80 detector unit on the floor by the root end,
on its side, with socket uppermost and alpha window close to the
root. The LCD-60 unit was connected to the RM-80 and showed
1059 counts after 23 minutes (46.04 counts/min.)
Timing was by the quartz-controlled kitchen clock which has a
second hand.
At this point the seaweed was removed without touching anything
else. After a further 23 min. the count was 2002, average counts/min.
= (2002-1059)/23 = 41.0 background, so the seaweed had added 5.04
counts/min. I then replaced the seaweed root, not necessarily in the
same position.
After a further 10 min. the count was 2485, giving a mean count rate
for background+seaweed of (2485-2002)/10 = 48.3 counts/min.
So there is no doubt that the seaweed contains something radioactive.
Natural or man-made? It is known that nuclear explosions produce
radioactive iodine isotopes, and that seaweed accumulates iodine.
The next question is: is there any point in taking counts along the stem
of the seaweed? Does it grow in such a way that a certain distance
along the stem corresponds to a certain point in time? Maybe a marine
biologist can help (Joanna S. in Perth - know anyone?)
Here in W. Scotland we are lucky in that the Gulf Stream brings us water
from the Caribbean, but on the West Coast of the U.S. you have a current
that brings water from E. Siberia, and who knows what the Russians have
been up to there. So maybe your clients in Alaska/Washington/Oregon/
California might like to try this experiment. (Also B.C. of course).
All the best,
I am a science teacher in the UK and I've found your site very useful for
ideas for experiments.
John
Radium A,B,C, etc. terminology is used as an easy method of
referring to Radium-Radon daughters, and their position in
the decay chain of Radium.
The Radium family includes Radium, Radon (Radium emanation),
Radium A (Po 218), Radium B (Pb 214), Radium C (Bi 214),
Radium C' (Po 214), Radium C'' (Tl 210), Radium D (Pb 210,
Radiolead), Radium E (Bi 210), Radium F (Po 210), Radium G
(Pb 206, Lead).
outside on the spoil heaps we got readings from 500-1500 cpm
in particular minerals showing a green tinge were the most active
on our return home i leached these green samples conc nitric acid
and concluded that copper was the green compound [ the radioactive
part remaining with the mineral on the filter paper]
when selling your product i think it would be an advantage to provide
a radioactive substance for investigation
both the us and uk and others forbid the proliferation of radioactive
materials--------------unless they are naturally occurring
would you be interested in purchasing such mineralogical specimens
which are natural and therefore mailable ??
Hi,
Just wanted to let you know I added a page to my web site showing some
results from just running the RM-60 counter for four months in my
apartment. I was able to measure radon from the gas used in my room
heater (well, I think anyway).
I have just returned from a visit to Derbyshire, UK, whith an RM80.
There are a number of tourist caves there, in mainly limestone country,
and some other caves which are open access. I was surprised to find
quite considerable activity in one of the latter, especially where water
runs in cracks down the cave side. Near the tourist cave entrance is a
teashop, and I noticed a small ventilation unit built into the hillside
next to it. This presumably was part of the ventilation system for the
tourist caves. When holding the RM80 next to the fans, a large increase
in count rate was noted, maybe 20 or more times background, but as I did
not have my laptop with me, measurement was not possible.
I certainly wouldn't want to spend too much time in the caves, as miners
have done for a couple of hundred years at this site!
Dear Sirs:
Was curious and pleased to find you on the internet to see if the
software had been updated in the past few years. Could you furnish an
update if it has?
Overall, I wanted you to know that I consider your product
outstanding and among the best device I've ever obtained in 25 years of
working with computers. It has always been reliable, easy-to-use, and
does what it was intended for in an excellent manner. I wish you much
continued success.
Richard L. Hoffmann, Ph.D..
Gamma photons are very powerful, some so powerful they contain
enough energy to resolve into electrons.
Think about that. It's amazing to wonder the process which brings
about cosmic rays! Is this with which star ships are powered?
Return to index page?
Klaus H.
Klaus Halbach
Sr. Physicist, Emer.
Lawrence Berkeley National Lab.
Personal aspects aside, very interesting experiment. Of course it goes
without saying, may vast recuperative force be with you!
Thank you for the dead time information. Because of unexpected health
problems I have not been able to absorb all the other information you sent,
but will read + respond to it when things get less hectic. Yes, it is ok to
put the description of my use on the net, with name + e-address. If it
leads to too many responses that I should answer to, I can always answer
with a generic letter. Another obvious use of the RM-70 may be monitoring
radiation therapy with radioactive implants.
Best regards,
Klaus.
To: Bryan Boardman, Aware Electronics, Wilmington, DE
From: George (Sassoon) geosas@aol.com
I took an old farm gate hinge, a strip of rusty mild steel (presumably)
about 2.5" wide x 1/4" thick, and built up a big fat weld on it about 2" dia.
I then plunged it into water, and as soon as cool enough placed it with the
weld upwards and one of your RM-80 detectors on top with the alpha window
over the weld. I had left it going half an hour in this position to
establish background.
NOTES ON EXPERIMENTS ON RADIOACTIVITY IN WELDS
Dear Bryan:
Bryan
Ira A. Wilner
** WILNER ASSOCIATES **
Broadcast Engineering Services
Email: bdcst@vermontel.com
URL: http://www.vermontel.com/~bdcst
Hello Brian,
Subject: Radioactivity in seaweed
From: George (Sassoon) geosas@aol.com
Hello Aware Electronics,
...
I would like to ask why the daughter products of the radon are called
radium b, c and c' when there is no obvious connection with radium.
Thanks
From: Peter Mobberley Peter_Mobberley@compuserve.com
Subject: grampound
To: Aware Electronics aware@aw-el.com
hi bryan
thank you for your reply
i decided to go for your idea of an additional card to provide
COM3 and COM4 the rm-60 is thus accommodated
our trip to grampound road cornwall was very successful and
intuative--------------background here in the uk is 11 to 14 cpm
say 12.5
on arrival at grampound cpm in our cherokee was 120
just 10 times background !!!!!
73"pete
Subject: geiger counter monitoring experiment
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
http://shell3.ba.best.com/~beale/measure/index.html
-john
beale@best.com
From: hrbj
X-Mailer: Mozilla 4.0 [en] (Win95; I)
To: aware@aw-el.com
Subject: Radon in Caves
X-Mailer: Mozilla 3.01 (Win16; I)
MIME-Version: 1.0
To: aware@aw-el.com
Subject: AW-SRAD Version 2.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
I have had one of your RM-60 monitors for several years now. I
have used it on several occasions, my son used it for a couple of
science fair projects, and I had a heart test the other day which
involved being injected with radioactive thallium and I dug it out again
to measure how much residual radiation I was emitting- (a lot it turns
out, after 24 hrs 5600 MiP/hr). At 3 feet away from the monitor, I was
emitting around 400 MiP/hr.
I already personally own quite a lot of Aware Electronics Corp. radiation monitoring equipment and think it is absolutely first-rate -- and so do my students.
Emeritus Professor of Chemistry
Illinois Central College
One College Drive
East Peoria, IL 61635
At 04:59 PM 11/7/96 -0500, you wrote:
>Dear Sir or Madame:
> A friend of mine who is in high school needs a definition for what
>is a gamma counter. I believe she means an instrument that is able to count
>gamma radiation from gamma emitters. Can you please e-mail a simple
>definition of what this machine is, and what it is capable of doing?
>
>Thank You,
>
A gamma counter can be thought of as a photon detector-resolver.
A gamma counter causes the quantum photon wave to resolve in such
a way that it can be detected. The act of detection causes the
quantum photon to resolve.
This is Dave Padalino from the University of Buffalo. I just
ordered an RM-60 unit from you a week ago, and it is working great. There
have always been some concerns about the radon levels in basements around
the area of Liverpool where I permanently reside, and I have wondered what
the exact level of radiation was in my basement just in case. It put my
mind at ease when I found out that it was an average of 12.3 micro
Roentgens per minute when I tested it. A few years back someone I knew
had unusually high levels of Radon in their basement, so it's a help to be
able to visualize the levels of radiation with your graphing program
AW-srad. Thanks again for a fine product.
Email 
