Please Note: In the interest of variety, as of Aug. 31st 1998 11:00 pm we switched from a RM-60 + Fan-Filter to a RM-80 + Fan-Filter for the real time graphs on this web site (Fan-Filter Photos). We also moved the sensor to the basement area as opposed to the living room area. See last graph as well as Yes button for the latest RM-80 data.

Below is a graph generated with Aware's RM-60 feeding a leftover XT laptop.

It shows fluctuating Radon levels in southeastern PA covering several years. Radon levels measure between 0.5 and 2 pico curies per liter air. (Note: EPA's action levels equate 1 picocurie Radon / liter air with 0.005 Working Level (WL)).

Notice the large drops during certain storms, for example the "Blizzard of the Century" near the beginning of the plot. Also notice large spikes when northwest winds pass over Radon out gassing areas i.e Reading Prong. (NOTE: Text Info. about FAN-FILTER at bottom of this page).

Radon Fleas in Living Room

Now the RM-80 + Fan-Filter data. Note the huge increase in Radon decay product Sept. 17th 1999 when remnants of hurricane Floyd dumped 10 inches of water in this area in one day. The basement where RM-80 + Fan-Filter is located is on a hill and no water entered area. We think all the rain in such a short period of time pushed stored Radon out of the ground hence the huge spike. November 2002 we noticed that for the last year or so scaling from the basement's cinder block wall was accumulating on the RM-80 + Fan-Filter so we installed a new filter and moved the system a few feet to underneath the electrical breaker box on the wall.

Radon Fleas in Lower Room

Radon Fleas in Lower Room

(Scroll beyond Yes button for more text).

View graph with just last few days to inspect daily pattern?


NEW ADD-ON AVAILABLE FOR INCREASED SENSITIVITY to RADON DECAY PRODUCTS, NUCLEAR FLEAS (Fan-Filter Photos)

Aware Electronics has available compact, high quality, fan-filter add-on assemblies for increased sensitivity to presence of Radon gas, and/or airborne radioactive dust (NUCLEAR FLEAS). These make an excellent addition to your RM unit, especially with the Aw-graph program. With the add on fan-filter, sensitivity to Radon is so great that you can easily graph ambient Radon levels, less than 1 pico curie Radon per liter air, as demonstrated in the Aw-graph plot above, which was generated with an RM-60 and Fan-Filter. It is fascinating to observe changing Radon levels, even if you don't have a Radon problem.

Excellent for use in a teaching Science lab as well.

Track hour by hour, day by day, month by month variations, due to weather, etc. Radon daughters RADIUM B and C+C' (half-life: 27 mins. & 20 mins.) collect on the washable filter. When you turn off the fan, the software plots a beautiful decay curve, as the RADIUM B & C+C' decay into Pb-210, with a halflife of 22.26 years. Determine Thoron percentage by analyzing the decay curve (see description of MAKDECAY below) or other rare but highly dangerous airborne radioactive particles. Assembly straps over RM unit's Alpha - Beta window.

Alpha-Beta-Gamma emission is detected and graphed. Set alarm. With the RM-60, an increase of appox. 7 CPM/picocurie Radon/liter air is observed. (RM-70: 70 CPM, RM-80: 168 CPM) The radioactive material collecting on the filter is the same that can collect in the lungs. This is why radioactive dust, from whatever source, represents such a serious health threat.

The standard fan-filter unit includes 2" x 2", 12 VDC, 100 ma fan with solid state circuitry (for brushless electronic commutation), stainless steel ball bearings, locked rotor & polarity protection. A regulated 120 VAC to 12 VDC power supply is included. The power supply is regulated to eliminate variation in fan speed due to ac line voltage fluctuation.

The compact assembly is held in place over the RM-60, 70 or 80 Alpha-Beta window with supplied VELCRO strap. Air enters around the window, by way of openings into lower spacer-diffuser, travels up through filter, then through fan then out top of unit. Collected radioactive daughters radiate from filter down to RM window. Since the Radium B & C daughters are continually decaying into Pb-210, which is 427,000 times less radioactive than Radium B & C, the plot is directly related, in a linear fashion, to Radon levels. As indicated above, when the fan is turned off, after perhaps 2 hours the radioactivity of the filter will decay to a level indistinguishable from background. With continuous operation, each filter should last many months before washing or replacement. Five easy to change replacement filters are included.

The package includes: Fan - Spacers - Diffusers, 5 filters plus filter mounting, Velcro strap, regulated power supply. Write "FAN-FILTER" "USA" or "OVERSEAS" or "WITHOUT POWER SUPPLY" on order form.

Fan-Filter Add On plus MAKDECAY program price list:
With USA power power supply (120VAC to 12VDC regulated):-----$79.00
With Overseas power supply (105-250VAC to 12 VDC regulated):-104.00
(Overseas includes adapters for: Europe, England, Hong Kong, Africa, Israel, Asia, Middle East, Australia, S. America, Caribbean, USA)
Without power supply (tinned power leads):--------------------64.00

Included with each Fan-Filter order is the program MAKDECAY.EXE (normally $39) which generates pseudo decay curves with controllable amounts of RaB, RaC+C', Pb-212 for superimposing on a real decay curve, using AW-GRAPH or a spreadsheet. (A MAKDECAY plot can be found elsewhere in this literature pack). This aids in verifying Radon decay products and Radon versus Thoron.

The MAKDECAY program is superb especially with AW-GRAPH, even without the FAN-FILTER. Collect RADON daughters - Nuclear Fleas from outdoor air by sucking air through a coffee filter with a vacuum cleaner for 2 minutes, plot the decay curve with AW-GRAPH then analyze with the aid of MAKDECAY. To order MAKDECAY ($39) without the FAN-FILTER write "MAKDECAY" on order form.


As regards using the RM-80 without the Fan-Filter for measuring Radon indirectly:


Underground Radon

"In the tightened boreholes, radon in air concentrations were measured indirectly with Aware RM-80 Geiger-Mueller counters. Comparison with Alphaguard and Sarad radon monitors in the radon room at the Centre Universitaire and simultaneous measurements with a flow-through Radim radon monitor (Radim) in a borehole showed a very good correlation between radon concentrations and the gamma dosage from the Geiger counters. The sensibility and resolution of Radim radon monitors and Aware Geiger counters are similar. An advantage of the use of passive Geiger counters is ease of installation and the lack of active pumping with the resulting pressure perturbations in the borehole. Any influence of exterior factors such as temperature or atmospheric pressure can be neglected":

Influence of variable stress on underground radon concentrations.
Also found here:
Influence of variable stress on underground radon concentrations.

In addition see:
Real-time indoor radon exposure in the city of Zacatecas, Mexico.
Also found here:
Real-time indoor radon exposure in the city of Zacatecas, Mexico.


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