Re: Kicker news (good)

[Robert Carey <carey@buphy.bu.edu>]

Dear guys,
     Nice sleuthing. It was very interesting to follow all the
inquiries and deduction, even if I lost the office pool as to
the ultimate source of the problem. (I had fingered the WFDs).

                                     Cross fingers,
 				    Rob


On Fri, 2 Dec 2005, Brendan Kiburg wrote:

> Dear Colleagues,
>  This morning we discussed with the hallendienst our plans.  They
> explained that due to time constraint, we should not first look in the
> top/down access ports, but rather we should move or wait until Monday.  We
> decided to move and they disconnected the kicker.
>
>  As the upstream bellow was removed, the SU identified that the
> collimator was no longer in position.  He said that it was at already at
> an angle relative to vertical (~45 degrees), and that it fell
> further when they removed the bellows.
>
>  Based on what the SU told us, we fully believe the collimator
> was in electrical contact with the upstream deflector plate and the
> beampipe at the time of opening.  We remeasured the resistance between the
> fischer connector in HV1 and ground and obtained >20 MOhm , so the short
> appeared to be gone.  At air, we reconnected the power and ground and
> turned on HV2 as a control in the fixed frequency mode.  We
> then ramped up the voltage on HV1 and found no breakdown and we were able
> to achieve +9 kV on HV2 and -9 kV on HV1. We note that
> there was no Red LED on card 13, but we concluded yesterday this is a
> problem with the optical fiber and not a problem related to the
> breakdown.  This was our reasoning for stopping at 9 kV for the time
> being.
>
>  As a result of our findings, we believe there is clear evidence the
> collimator was responsible for the breakdown.  We have removed the
> collimator, as there was damage to the nylon ends inserted in the set
> screws.  We made the working decision to return to vacuum without
> inserting the collimator, but we have left open the option of reinserting
> it as early as next wednesday if we see significant evidence that we need
> it for beam quality.
>
>  We are currently pumping the beamline, which will take on the order of 8
> hours.  We can then verify that everything still works, and continue with
> our measurement program.  If there are any further problems, we will
> communicate them to all of you.  We will send another email later tonight
> when we have verified the repair was succesful.  Thanks for all the
> efforts and communication; we appreciate it.
>
> With guarded optimism,
>
> Brendan and Peter
>