Re: accel monitoring

[Keith Welch <welch@CEBAF.GOV>]

At 08:15 AM 10/3/96 -0500, you wrote:
>But CEBAF is a CW accelerator (ignoring the micro
>structure in the beam due to the RF).  Using a proportional
>based detector at a pulsed accelerator is generally not
>possible.


We can, and often do (during tuneup and diagnostics) run in a pulsed mode,
typically at 60Hz.  Pulse width can be varied, typically 1 - 250 uSec.

I think one reason we're ok with the proportionals is that this is area
monitoring outside a very thick shield, and it appears that the pulse
structure is flattened or "spread out" such that it is not too evident
outside the shield.
But I don't know if we'd be able to use them if we had a 1usec pulse at 1 Hz.

The system I described for inside the tunnel does not work well during
pulsed mode because it is not beam sync'd.  This is something being added,
as I understand it.  I would assume that in principle one could apply this
idea to area monitoring as well, but that's way out of my balywick.
Keith Welch
Thomas Jefferson National Accelerator Facility
Newport News VA
welch@cebaf.gov