RE: Kicker news (good)

[Mulhauser Francoise <francoise.mulhauser@psi.ch>]

Dear Brendan and Peter,

Whah.... This is great and very good news.

Yesterday night, during our telephone discussion, I was at the same time
very confident that the collimator HAS to be the faulty guy, and could not
believe that it would be so easy.

Your decisions are the most efficient and you should continue to pump.
Please wait until the pressure is down to 5x10-5mbar to start the separator
and kicker. As already mentionned, you can open manually the valve between
the separator and kicker when pressure is low 10-4 (ask M.Koller to tell you
where to look for it. It is in a rack, one floor below the magnet
powersupply.)

ps. Brendan, I did not get your email. I got only the reply from Mike.
Something is strange in your mailing list.

Best regards
Francoise 

-----Original Message-----
From: Michael Barnes
To: kiburg@npl.uiuc.edu
Cc: Gary Wait; Peter Winter; Michael Barnes; Mulhauser Francoise;
kammel@npl.uiuc.edu; hertzog@uiuc.edu; michael.barnes@triumf.ca; Robert M
Carey; Anatoly Gafarov; rmcnabb@uiuc.edu; claude.petitjean@psi.ch
Sent: 02/12/05 11:31
Subject: Re: Kicker news (good)

Dear Brendan and Peter,

Congratulations: I am very pleased that the breakdown is caused by
something as simple as the collimator falling out of place and that it
is
not a "wear out" mechanism of the Fischer socket.
Look forward to hearing that everything is confirmed to be working
later.

Re card 13: please check the backplane to ensure that the connections to
the fast grading capacitors are not shorting against the terminals on
the
back of the blue connector (this can easily occur during voltage grading
and would cause the red LED not to be lit). Otherwise, as we concluded
yesterday, it is probably the fibre optic cable.

Best regards,
Mike

> 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
>
>