Beni's PMT replacement email

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To: paul eugenio <eugenio@fsu.edu>, alexander ostrovidov <ostrov@jlab.org>,
        Mark Ito <marki@jlab.org>, zihlmann@jlab.org,
        Fernando Barbosa <barbosa@jlab.org>
From: Beni Zihlmann <zihlmann@jlab.org>
Subject: PMTs for TOF 
Date: Mon, 27 Jun 2016 09:27:29 -0400

Hi All,

we have to buy new PMTs to replace the ones we may have damaged too
much after this fall run.  This would include a maximum total of 32
tubes to cover the inner most paddles including the first long wide
paddles on either side of the beam line.

We need to find out what we actually want to buy. only the tubes or
the full assembly. Since we need to run the tubes at much lower HV
(gain) to reduce the current we may need to modify the voltage divider
on the base, or we go to use 8-stage tubes rather than the 10-stage
tubes we currently use.

We also have to discuss how we want to operate the TOF this fall, with
as low a HV as possible to reduce the currents in the PMT and change
the dynamic range of the ADCs.

I include Fernando in this email as he may have some good advice for
us.

We need to discuss this issue tomorrow in the TOF meeting.

Best Regards,
Beni