[ RadSafe ] Beat phenomena and health physics

[Bill Prestwich]

I think you are referring to energy summing, which does occur, particularly
from cascading gamma-rays such as the 1.17 and 1.33 MeV gammas in 60Co.
These are emitted almost simultaneously and if both interact in the detector
or body leave the sum of the energy. This is different from the standard
idea of beats between oscillations which alter the amplitudes in a
continuous manner depending on the phase difference. In that case the
resultant amplitude can vary from the sum to the difference depending on the
phase difference.

Bill

-----Original Message-----
From: radsafe-bounces at agni.phys.iit.edu
[mailto:radsafe-bounces at agni.phys.iit.edu] On Behalf Of JPreisig at aol.com
Sent: Tuesday, February 24, 2015 12:12 PM
To: radsafe at agni.phys.iit.edu
Subject: Re: [ RadSafe ] Beat phenomena and health physics

Radsafe/Bill,
 
     In Health Physics, the effects may not be  significant.  In certain
sensitive physics experiments, the effects may be  significant.
 
     Joe Preisig
 
 
 
 
In a message dated 2/24/2015 9:24:48 A.M. Eastern Standard Time,
prestwic at mcmaster.ca writes:

Hi  Joe,

I think, since photons are emitted randomly, that the interference  effects
that occur with electrically produced sinusoids are not  significant.

Bill

-----Original Message-----
From:  radsafe-bounces at agni.phys.iit.edu
[mailto:radsafe-bounces at agni.phys.iit.edu]  On Behalf Of JPreisig at aol.com
Sent: Sunday, February 22, 2015 10:57  PM
To: radsafe at agni.phys.iit.edu
Subject: [ RadSafe ] Beat phenomena and  health physics

Dear Radsafe,

The phenomena  of beats (see your undergraduate  text in
physics/mechanics) involves  what happens when 2 or more fundamental
frequencies of a system are close  in frequency (or Energy)  to one another.
Two such sinusoidal  signals (or more) produce sum and difference
frequencies, which can be  important in problems.

I've been discussing beats  concerning the  fundamental wobble frequencies.
I also said  something perhaps about beats  and the Sodium doublet.

Another situation where beats might be important  is in  health physics
and perhaps even physics.  We Health Physicists   measure gamma and other
spectra using a MultiChannel Analyzer and  similar  equipment.  There may be
times when our gamma spectra  have peaks that are  close to one another and
may produce beat (sum  and difference frequency)  peaks.  Do we observe such
peaks in  our spectra???  Will these beat  phenomena affect our  physics
results???  Quite possibly.  These extra  peaks may  affect spectral
stripping and other results.

Remember,   E = h x nu, where nu is the  frequency in atomic  and/or 
nuclear physics.

Perhaps physicists  doing sensitive experiments  account for such beat
phenomena.  I  don't remember hearing about beat  phenomena in my Health
Physics  courses.  I first heard about beat phenomena  in a physics course
or
two.  Then I heard about it again in geophysics   research.

Beat phenomena might affect our every day  Health  Physics work???  Oh my.

I seem  to remember Cesium-137 having closely  spaced decay (energy) gamma
peaks.???

Regards,    Joe  Preisig





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