Re: Y-90

["Daniel Mackney" <photond@EARTHLINK.NET>]

My understanding is that Y90 is "Essentially" a pure beta emitter. The

photons that result are less than 0.0015% of the intensities at . The old

Radiological Health Handbook , Jan. 1970, showed this also as a

contridiction. Table II Detailed Nuclear Properties shows no gamma for Y90,

while the illustrated decay schemes show a photon and lists the following:

γ-1 1.734 (e-  0.0016%, e- /γ >30 e±/e- 3) mag spect conv, scint spect

(YuaT56a, YuaT57a) ..(γ-1 1.75 (e- 0.5%, e/γ very large) mag spect conv

(JohnO55) ... γ-1 (†γγ/†e-<0.0006) mag spect conv (RydH63b)

I agree with the fact that you do not measure Sr 90 decay by any gamma

method and in drinking water analysis at the prescribed levels of minimum

detection the time necessary to count the sample for possible Sr89

interference is also moot. Therefore everything rides on your ability to

perform good beta counting and  Sr and Y extractions.



Dan Mackney

Radiochemistry Manager

Waste Stream Technology



----- Original Message -----

From: <Jack_Earley@RL.GOV>

To: <radsafe@list.vanderbilt.edu>

Sent: Tuesday, February 12, 2002 3:19 PM

Subject: Y-90





> I was "somewhat" surprised today to hear a nuc safety rep say that since

> Sr-90 is pure beta, it doesn't need to be considered in a shielding

> calculation. When I mentioned that it's in equilibrium w/ Y-90, which

emits

> some significant gammas, I was even more surprised to hear him say Y-90

> doesn't emit gammas. Rather than address it further in the meeting, I

pulled

> up Grove's (Kocher) decay program, which showed only two betas for Y-90;

no

> gamma. But it then lists Y-90m w/ seven gammas ranging from about 2 keV to

> 0.7 MeV. My day for surprises, I guess--I've always associated Y-90 gammas

> w/ 2+ MeV. Sure enough, my 15th edition of the chart shows 202 keV and 2.2

> and 2.3 MeV gammas. So, since I'm apparently not the brightest bulb in the

> lamp, can someone tell me why there's such a difference?

>

> Jack Earley

> Radiological Engineer

> ************************************************************************

> You are currently subscribed to the Radsafe mailing list. To unsubscribe,

> send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

> radsafe" (no quote marks) in the body of the e-mail, with no subject line.

You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/

>



************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line. You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/