Pahrump, Nevada is located within the potential fallout zone
of west coast nuclear plants. The effect of a nuclear accident
would depend on the extant wind
patterns and the distance from the plant. The San Onofre plant is located near an earthquake fault and, as
the events in Japan demonstrate, independent monitoring of radiation is needed.
A nuclear disaster is not academic, remote, impossible, and they don't always happen
somewhere else.
Click to learn the horrific story of the children of Chernobyl,
because this could happen here.
Now get a classic V-715 radiation instrument retrofitted with modern electronics !
The V-715 is a cold war era detector used to measure the high, R per hour,
radiation levels that might be encountered after a nuclear attack. Its ionization
chamber is orders of magnitude less sensitive than a Geiger Muller tube however
and it did not serve the usual purpose of a Geiger counter - until now !
Range of retrofit instrument is .010 to 99 millirem per hour
Calibration is based on the rating of the SBM-20 Geiger Tube at 29 counts per second
per mr per hour.
Retrofit units with internet serial output are now available for $349. A programmed
netburner server to complete your internet Geiger counter is an additional $225.
Hosting on this site is then free.
Click picture below for more information on this project. Retrofitted are internet enabled !
Internet mode works with a Netburner server and presentation
will be like the data on the right side of this page. We will offer preprogrammed
Netburner modules and web hosting on this site for your internet Geiger counter project.
Picture below shows test of retrofit circuit board using
a 1940's era radioactive, uranium oxide, plate. Reading is mostly
beta and registers 1.572 mR per hour.
This site records and displays hourly
radiation data for one week or 168 consecutive hours; I generally
reset it on Sunday at midnight to
synchronize the clock. In addition to the current count and previous
hour result, the display
to the right will show the most
recent 8 hours of data after more than 8 hours have passed since reset.
After 4 hours the average of all data for the week as well as the standard
deviation is displayed. Click the link above to view data for the entire
current week. Note that work on software, power failures, and other issues
may occasionally cause a loss of accumulated data.
The Geiger counter originally used the same 6993 Geiger-Muller tube as the CDV-700
Geiger counter that
was distributed for Civil Defense use during the cold war era. On 4/28/2011
I upgraded to a larger and more sensitive Russian SBM-20 mounted on a
new circuit board. The microprocessor is a Freescale 9S12C that sends data to
a Freescale MOD 5270 for web presentation.
The dimensions of the tube and the probability of an ionizing event within its volume constitute
the only calibration. Sensitivity of the SBM-20 is 29 counts per second at 1 mr per
hour and all data is based on that fact. Since background radiation
is very low the unit accumulates counts for one hour. It displays the
running counts after the elapsed minutes in the current hour, and calculates
the CPM (Counts per Minute) and the radiation based on that data.
During the first hour after reset the previous hour data and Millirem daily record will read zero. The
CPM and daily dose rate data will not update during the first two minutes of a
data collection interval.
A typical reading is 0.011 millirem per hour, this corresponds to an annual dose of
96.4 millirem. For reference, the global average natural exposure is 240 millirem
so we here in Pahrump enjoy relatively low radiation.
Upon completion of a one hour sample the result is
stored in the "Counts previous hour" value and the radiation exposure in millirem
is updated. For those who prefer Sieverts as a radiation unit note that
1 millirem = 10 microsieverts
For information on advertising, general inquiries, and support for starting
your own on line Geiger Counter - please write !
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