Don, nice summary. Please add the word "activity" to the Ci-specimen explanation, add neutron Q factor and
then post the article to

http://tech.groups.yahoo.com/group/HomeRadLab/

THANKS

Geo

--- DonJordan@ramservicesinc.com wrote:

From: "Don Jordan" <DonJordan@ramservicesinc.com>
To: <GeigerCounterEnthusiasts@yahoogroups.com>
Subject: Re: [GeigerCounterEnthusiasts] Newbie needs pointing in the right direction.
Date: Mon, 18 Feb 2008 11:58:48 -0600

Becquerels [Bq] and Curies [Ci] measure how much radioactive stuff you have while Rems and rads (as well as Sieverts) measure how much radiation damage is being done to living tissue. The rad measures how much ionization energy the radiation deposits in your body while the rem is intended to measure how damaging that energy may be:  rems = rads*Q

The Quality factor Q is 1 for beta, gamma, and X-rays.  The Q factor for neutrons varies from 2 to 11 for neutron radiation depending on the neutron energy.  Alpha radiation cannot penetrate into living tissue from outside the body, so its Q factor of 20 only applies to internally deposited alpha emitters.

Note that we do not measure amounts of radioactive material by weight (e.g., grams) because that doesn't tell you much directly.  Instead we use the ACTIVITY of the sample measured in Bq or Ci because this tells you directly how much radiation is coming from a given specimen and you can then directly calculate the radiation dose you would receive.

The "average" radiation exposure from background sources in the USA is about 350 millirem per year or about 1 millirem per day. Hope this helps.

----- Original Message -----
From: carpentershop
To: GeigerCounterEnthusiasts@yahoogroups.com
Sent: 15 February, 2008 10:48 PM
Subject: [GeigerCounterEnthusiasts] Newbie needs pointing in the right direction.

Hi guys,

I found this group from an Ebay seller a while back and finially
joined up a few days ago. Interesting group...

I am in the countertop business, granite, quartz, solid surface and
laminate, as well as kithens. The current controversy over granite
is what has motivated me to learn about Geiger counters and hopefully
be able to understand measuring radiation better.

I do have a few question that I would like the groups opinion on.

1. Has anyone done any testing on granite materials?

Some of the granites in studies show as much as 32 Bq per square
meter per day. I noticed that you guys talk in Rems and Rads, the
conversion gets my head spinning at times, no head for math at all.

2. Can anyone recomend a good Geiger counter for testing granite
materials that we offer the public?

I am not sure I buy the scare mongers, but some of the studies are
calling for the testing of granite and if they are concerned, I
figure I had better get ahead of the issue.

I've been reading the new posts, hadn't found the time to go back to
the old ones, but there seems to be a lot of talent here along with a
passion for the feild.

Thanks,
Al

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