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Radiation Dose from X-Ray Machine

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Alessandro95

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I am currently doing radiation testing on an IC and would like to infer from the target current from the x-rays and tube voltage (30kV) so a total of 3W of X-ray power on the chip, the amount of radiation in rad. Is there a way to perform this calculation as I am quite stuck?

Thanks in advance.
 

dick_freebird

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You would need to know a few things, relating to
radiation transport / shielding and absorbtion at the
X-ray energy in question. The literature for rad hard
microelectronics tends to center on 1MeV gammas
(which are very penetrating) while the 10keV X-rays
produced by Aracor machines can't even get past the
package lid / overmold.

The amount of power "on the chip" is not at all the
same as what's hitting the top face. Some diverges
and misses altogether; some doesn't make it that far,
some goes right on through, some drops energy and
does "TID stuff".

The most efficient approach might be dosimetry. But
this again is subject to the material discrepancies
between dosimeter and "victim". If you have a similarly
packaged and constructed photodiode, whose volume
is known and whose volumetric efficiency as a
photocurrent source is also known or surmisable,
the raw photocurrent reading could give you rad(Si)/sec
received dose rate from the tube, and time shot, the
total dose.

Irradiator manufacturers such as Hopewell Designs
(big X-ray irradiators), Aracor (who have ditched the
semiconductor test business in favor of homeland
security gravy train), maybe the specific mfr of your
setup, might be able to offer at least penetration /
absorbtion vs keV curves.
 

BradtheRad

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Photographic film responds to Xrays. It was the accidental method by which Wilhelm Conrad Roentgen discovered them.

History of Radiography:

https://www.nde-ed.org/EducationResources/CommunityCollege/Radiography/Introduction/history.htm

Edit: Sorry, I had it wrong...
Roentgen discovered Xrays while working with fluorescent crystals and a cathode-ray tube. The photographic plates and rock in a drawer appear in the story about French scientist Henri Becquerel discovering natural radioactivity.
 

dick_freebird

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There are film badge dosimeters but these are for levels
far below what usually affects semiconductors - more
for go/no-go, human safety applications. And they are
very far in details of construction, from the article under
test.
 

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