[ RadSafe ] Beat phenomena and health physics

[Edward Tupin]

One of the factors that minimizes/eliminates the "beats" in health physics spectroscopy is the dead time phenomenon in the detectors. 
that is, once a photon has interacted with the detector crystal, the crystal is "dead" and doesn't react with another photon until it has recovered. Thus it would be rare for beats to show up in gamma spectra. Sum peaks do occur - when two photons hit the detector at the same time, the energy is additive and produces a peak that shows at the sum of the two energies in the component peaks. Ed Tupin
Cell: 202-631-3307
      From: "radsafe-request at health.phys.iit.edu" <radsafe-request at health.phys.iit.edu>
 To: radsafe at health.phys.iit.edu 
 Sent: Tuesday, February 24, 2015 1:00 PM
 Subject: RadSafe Digest, Vol 1781, Issue 1
   

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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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