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Re: Cathode vibration- how to dampen?



Hi,

We worried a lot about vibration at the SSC, for the central tracking chambers for GEM 
detector.

My recollections are 15 years old, but I recall that typical loadings were at 30 Hz, 60Hz, 
etc, with an exponentially decreasing amplitude with frequency.  These are mainly due to 
reciprocating machinery (source was ground test research at LANL).  At the SSC we very 
carefully tuned the resonant frequencies of our chambers to be in the middle of these, 
i.e. at 45 Hz, 90 Hz, etc.

Back at Yale we hired an engineer who was expert in modal analysis.  He and I set up a 
vibration test stand (accelerometer, scope with FFT, etc).  Fortunately our chambers were 
substantial, so we could make measurements with the accelerometer placed directly on them. 
  No such luck with FDC cathodes, though...


				Sincerely,
					Elliott


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  Those raised in a morally relative or neutral environment will hold
		    no truths to be self-evident.
				

Elliott Wolin
Staff Physicist, Jefferson Lab
12000 Jefferson Ave
Suite 8 MS 12A1
Newport News, VA 23606
757-269-7365

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