Re: [tlug] Measuring radioactivity at TEPCO Fukushima plant

["Stephen J. Turnbull" <stephenjturnbull@example.com>]

On Fri, Mar 18, 2011 at 1:31 PM, BALUTA Chris <baluta@example.com> wrote:

>    Each page has its own format, and most of the sites I have
> looked at employ yet another exposure unit: micro Grays.

1 gray = 1 sievert, basically.  However, sieverts account for
biological effects and type of radiation, while the grays is a purely
physical measure (joules/kilogram IIRC).

I'm not sure what the modern story is on the biological adjustments,
as the current SI definition of sievert apparently doesn't include
that correction anymore.  The type of radiation adjustment is still
there: gamma and beta get no adjustment, for alpha 20 sieverts =  1
gray, and for neutrons it varies with the energy of the neutrons
(single peaked).

Since we're looking at gamma (and maybe beta) radiation here, 1 gray =
1 sievert is more than good enough for government work.