TSSP: List Archives

From: "Malcolm Watts"
Date: Mon, 18 Jun 2001 09:04:30 +1200
Subject: [TSSP] Some Considerations

Hello Paul, all,
                 I pondered your note on where we are at and what 
needs to be done and have considered two points.

#1 - Top Volt msmt.  The real ugly sister.  There seems to be two 
possible routes, both of which can be verified as to their 
disturbance of the resonator. It is clear that any msmt must be 
"central" to the resonator axis to avoid distorting the electric 
fields around it. 

(a) A probe running up through the centre. This might consist of a 
*very* high resistance with a division resistor at the base to ground 
(bottom end of the coil). It would probably have to be shielded with 
a thick layer of insulation around the shield and compensated for 
inherent shunt capacitance.

(b) A similar probe running vertically from the top of the coil with 
instrumentation above it or an electrically isolated feed from its 
top.

Both of these may be checked for disturbance by F and Q msmts before 
and after. I don't see why doing such checks at low levels would be a 
problem as long as there is no corona n the probe at normal running 
voltages. 

#2 - Top voltage vs breakout.  We are all well aware that in normal 
repetitive running of a TC there is little correspondence between top 
voltage and streamer length. Therefore, any such relationship would 
have to be done in single shot mode to a grounded point in my 
opinion. FWIW, this is how I usually gauge the performance of a 
resonator and/or system before proper firing. This *must* be done 
while monitoring e-fields on the scope as more than a single transfer 
implies additional power lost in the primary so the effectiveness can 
be gauged by discounting discharges which result in multiple beats. 
This should prove reliable as an indicator of normal running voltage 
since we know that the low duty cycle of a repetitive TC does not 
allow "bangs" to build on one another.

I welcome comment and discussion on all of these points. We simply 
have to find a way of performing these measurements.

Regards,
malcolm



Maintainer Paul Nicholson, paul@abelian.demon.co.uk.