6/12/98

Hi, again-



I remember reading somewhere that we should not wrap contianers of uranyl

acetate in aluminum foil. Why is that? Is there a danger of

bremstrunghumuhumunukunukuapuaa radiation? (Sorry, it's Friday afternoon

and I clearly don't know what I'm talking about.)



Aloha,

Tina



http://www.pbrc.hawaii.edu/bemf/microangela

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

* Tina (Weatherby) Carvalho * tina@pbrc.hawaii.edu *

* Biological Electron Microscope Facility * (808) 956-6251 *

* University of Hawaii at Manoa * http://www.pbrc.hawaii.edu/bemf*

The real reason for not using aluminum foil is that the acetate ion will

decompose the aluminum (if liquid dribbles down the side of the container

--- gasp --- and onto the foil). This generates a crumbly mess that is

contaminated with Ur to boot. If one carefully pipettes the UrAc, the

contact is avoided. We have used aluminum to cover our UrAc for several

decades and only once did the Al decompose (in out student laboratory).

John J. Bozzola, Ph.D., Director

Center for Electron Microscopy

Neckers Building, Room 146 - B Wing

Southern Illinois University

Carbondale, IL 62901

U.S.A.

Phone: 618-453-3730

Fax: 618-453-2665

Email: bozzola@siu.edu

Web: http://www.siu.edu/departments/shops/cem.html

Tina,



UrAc is thought to be sensitive to light - especially UV type of light

found in fluorescent light and sunlight. Causes breakdown of the stain and

possible precipitation. Very little radioactivity is present - but some is

there, so be careful.

Dr. John Bozzola, Director

Center for Electron Microscopy

Southern Illinois University

Carbondale, IL 62901

Phone: 618-453-3730

Fax: 618-453-2665

bozzola@siu.edu

I am not sure why one wouldn't wrap UAc containers in Al foil, but

it has nothing to do with radiation. The only kind of radiation which will

penetrate the bottle to interact with the foil would be gammas from some

of the daughters of the U. If one had a very thin-walled container and a

very energetic beta, one might have to worry about brehmsstrahlung radiation

(It's Tuesday morning & I'm still awake), but since its production goes

as a power of Z, Al is one of the better metals for avoiding this problem.

Be is the best mechanically sound metal for avoiding brehmsstrahlung, but

has other problems. Plastic is another good material for avoiding it.

Yours,

Bill Tivol

tivol@wadsworth.org

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