Last week, Michael, Karen, and I increased the ramp rates on the HV for
the WC and LADS from 100 V/s to 200 V/s. This had the affect of
shortening the deadtime when filling the ring. Consequently the
current at which we should dump the beam is higher than normal. I
suspect that for 140 mA injection that we should be dumping at 95 mA
for optimal luminosity.
To calculate the optimal current use the equation:
I_dump = I_inject * exp( -t_live / tau )
there I_dump and I_inject are obvious, tau is the average beam
lifetime and t_live is the live DAQ time for each fill as calculated
by:
t_live = SQRT( 2 * t_dead * tau )
where t_dead is the deadtime during a fill from the time when the DAQ
stops until it starts again. Currently I think t_dead is around 1.5
minutes, tau is around 20 minutes thus t_live should be 7.75 minutes
and i_dump is 68% of i_inject.
Cheers,
Douglas
26-415 M.I.T.
Tel: +1 (617) 258-7199
77 Massachusetts Avenue Fax: +1 (617)
258-5440
Cambridge, MA 02139, USA E-mail:
hasell@mit.edu
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:31 EST