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RE: Kicker grading measurement

Without seeing your routing of the ground wire, to the central (Fischer)
ground, and the routing of the probes coaxial wire to the scope I cannot
comment further on whether this might be the problem. In addition the
placement of the oscilloscope, relative to the open cabinet door, will
effect the noise.

As I mentioned in my earlier email, your x1000 probe is sensitive to
capacitive pickup which will be modified by the angle you hold the probe
at. I don't believe the measurement shown in up_01.png. For example the
peak, which you put the horizontal cursors on, occurs DURING the falling
edge of the voltage: if there was a timing problem with the cards the
peak would occur at the START of the falling edge.

I suggest you measure up_01 several times and store the results: if
there is a measurement noise problem, e.g. which is dependent upon the
angle of the probe, you will obtain several very different measurements.

I would be VERY surprised if the vacuum pump has any effect at all.

Cheers,
Mike


-----Original Message-----
From: Peter Winter [mailto:peter.winter@psi.ch] 
Sent: Tuesday, May 02, 2006 12:52 PM
To: Mike Barnes
Cc: Mulhauser Francoise; kiburg@npl.uiuc.edu; kammel@npl.uiuc.edu
Subject: Re: Kicker grading measurement

Mike Barnes wrote:

>The ground wire should be as short as reasonable possible and it should

>be positioned so as to minimize its inductance and also pickup from the

>HV pasts of the circuit.
>
We used the same grounding cable like last year so the length is the
same.

>What is the HV voltage and frequency for your measurement?
>  
>
We were at 3.4 kV with a 1mus TTL signal at 1kHz.

> Was this piece used during the latest measurements?.
>  
>
Last time and this time we only had a 3cm long alligator clip at the end
of the HV probe.

>Where did you ground the HV probe for your measurements?
>  
>
The ground is attached to the metal plate inside the kicker just at the
whole where the fischer plug goes through. It's the same spot like last
year.

Peter