Readings not Equalized
the Monitoring Stations are broadcasting raw
radiation counts from their
Geiger counters, with out adjustment for different count rates existing between
various Geiger counter designs. For instance, models built around a
" (see Map Legend) style of Geiger-Mueller tube typically
have about a 3 times count rate over Standard tubed models, in that their readings in
should be expected to average about 3 times higher, anyway.
How the Radiation Map Works:
An ever expanding number of Radiation Monitoring Stations across the country
In use are various models of Geiger Counters, they upload their Radiation
Count data in real time to their computer using a Data Cable, and
then to the Internet and to this web site, all is accomplished through
GeigerGraph for Networks software. This is an automated system - there is no manual posting of data required.
How to Read the Map:
Referring to the Map Legend at the bottom left corner of the map,
locate Monitoring Stations around the country that are contributing
radiation data to this map as you read this, and watch the numbers on those
monitoring stations update as frequently as every minute (your
browser will automatically refresh). The numbers represent radiation
Counts per Minute, abbreviated CPM, and under normal conditions,
quantify the level of background radiation, i.e. environmental radiation
from outer space as well as from the earth's crust and
air. Depending on your location, your elevation or altitude, and your model of Geiger counter, this background radiation level
might average anywhere from 5 to 60 CPM, and while background
radiation levels are random, it would be unusual for those levels to exceed
100 CPM. Thus, the "Alert Level" for the National
Radiation Map is 100 CPM, so if you see any Monitoring Stations with CPM
value above 100, further indicated by an Alert symbol over those
stations, it probably means that some radioactive source above and beyond
background radiation is responsible.
Notice the Time and Date Stamp at the bottom center of the Map.
That is Arizona Time, from where we service the Network, and your indication of how recently the Radiation Levels have been updated
to the Map.