Re: tagger magnet spec (fwd)

[Elke-Caroline Aschenauer <elke@jlab.org>]

Dear all,

some remarks from Jay to the specs for the tagger I send him.

cheers elke




 ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
  )    `\                                                  -
 /    '. |                                                  +
 |       `,              Elke-Caroline Aschenauer            =
  \,_  `-/                                                    -
  ,&&&&&V         Jefferson Lab                                +
 ,&&&&&&&&:       HALL-D 12C / F381       121-A Atlantic Avenue =
,&&&&&&&&&&;      Mailstop: 12H5          Hampton, VA 23664      -
|  |&&&&&&&;\     12000 Jefferson Ave                             +
|  |       :_) _  Newport News, VA 23606  Tel.:  001-757-224-1216  =
|  |       ;--' | Mail:  elke@jlab.org    Mobil: 001-757-256-5224   -
'--'   `-.--.   |                                                    +
   \_    |  |---' Tel.:  001-757-269-5352                             =
     `-._\__/     Fax.:  001-757-269-6248                              -
            +=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+

---------- Forwarded message ----------
Date: Wed, 28 Nov 2007 18:35:25 -0500
From: Jay Benesch <benesch@jlab.org>
To: Elke-Caroline Aschenauer <elke@jlab.org>
Cc: Arne Freyberger <freyberg@jlab.org>
Subject: Re: tagger magnet spec

Elke,

The first thing that jumped out at me on first reading was at the top
of page 5: O-ring compression of 20-30%.  I had way too much trouble
with 20% compression on a system as a grad student.  I'd require
25-30% compression.

In the paragraph on vacuum box materials you might write "austenitic
stainless steel".  Aluminum to stainless welding is non-trivial.
e-beam welding may be the only choice.  This would be a big e-beam
welder.  I would specify the temperature range of operation so the
bidder can do the calculations on differential expansion.  Better yet,
to allow the bidder as much parameter space as possible specify the
temperature of the cooling water at the inlet.  The bidder will then
have to compute the temperature rise of the steel to determine whether
an aluminum chamber is feasible.  With 20 mm from pole edge to coils,
it should be possible to add enough thermal impedance to allow an
aluminum vessel.

If you can live with 10 ppm power supply stability you'll save some
money.  I think that is Danphysik's standard.  Check.

On page 6, you don't give the unit for the nominal beam height.  It
has to be meters but you need to write it.

I couldn't click on the link to Yang's drawing using gpdf.  I'll check
tomorrow on a PC with Acrobat.

Jay