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Re: TOF/FCAL Supporting Documents (fwd)
Hall D PID Mail List:
HI all,
I realized we should probably post these comments to halld-pid in case
there is other input.
Cheers, Elton.
Elton Smith
Jefferson Lab MS 12H5
12000 Jefferson Ave
Suite # 16
Newport News, VA 23606
elton@jlab.org
(757) 269-7625
---------- Forwarded message ----------
Date: Mon, 16 Apr 2007 04:34:01 -0400 (EDT)
From: Elton Smith <elton@jlab.org>
To: Elke-Caroline Aschenauer <elke@jlab.org>
Cc: Matthew Shepherd <mashephe@indiana.edu>, Tim Whitlatch <whitey@jlab.org>,
Chuck Hutton <huttonc@jlab.org>, Elton Smith <elton@jlab.org>,
Alex Dzierba <dzierba@indiana.edu>
Subject: Re: TOF/FCAL Supporting Documents
Hi Elke and Matt,
We use mu-metal shields in CLAS to shield 30 G with no trouble. I can dig
up the clas notes on the subject. Going beyond that, you need multiple
layers and/or soft iron/mu-metal combinations.
Cheers, Elton.
Elton Smith
Jefferson Lab MS 12H5
12000 Jefferson Ave
Suite # 16
Newport News, VA 23606
elton@jlab.org
(757) 269-7625
On Fri, 13 Apr 2007, Elke-Caroline Aschenauer wrote:
> On Fri, 13 Apr 2007, Matthew Shepherd wrote:
>
> Hi hi,
>
> okay very quick becaue I'm on the run to the airport. I will look to the
> nim paper to see some of it.
> But I'm very sure that with normal mu metal you can shield max some gauss.
> of course you can put really several layers around it than from layer to
> layer it gets less saturated, but in generell and we have done this more
> than ones for our tubes in hermes you use a soft steal shielding with a
> mu-metal layer inside.
>
> There is some more modern metal to shield tubes, which I have to find the
> name again, which is advertised for medium fields.
>
> Cheers and have a nice weekend
> elke
>
>
> > Date: Fri, 13 Apr 2007 17:16:45 -0400
> > From: Matthew Shepherd <mashephe@indiana.edu>
> > To: Elke-Caroline Aschenauer <elke@jlab.org>
> > Cc: Elton Smith <elton@jlab.org>, Tim Whitlatch <whitey@jlab.org>,
> > Chuck Hutton <huttonc@jlab.org>, Alex Dzierba <dzierba@indiana.edu>
> > Subject: Re: TOF/FCAL Supporting Documents
> >
> >
> > Hi Elke,
> >
> > You can find a NIM article on shielding studies done at IU several
> > years ago for the TOF and FCAL. (NIM A 533, 467) I didn't realize
> > that mu metal saturated at *that* low of a field. As far as I know
> > preliminary field studies show of order 100 gauss down around the
> > lead glass. If what you say is correct soft iron will be a
> > necessity. You can also find info in this paper about field strength
> > inside the tube as a function of distance from the tube. We would
> > plan this into the design -- it is also exactly what motivates the
> > use of light guides in the FCAL.
> >
> > -Matt
> >
> >
> > On Apr 13, 2007, at 8:22 AM, Elke-Caroline Aschenauer wrote:
> >
> > > On Fri, 13 Apr 2007, Matthew Shepherd wrote:
> > >
> > > Do we know what the field is because if it is bigger than 2-4 gauss
> > > mu-metal will not do the trick. Please if shields are desiged
> > > account for the fact that to have them really nicely working you
> > > need to
> > > have the shieled extentding by the tube diameter from the tube
> > > surface.
> > >
> > > bye elke
> > >
> > >
> > >> Date: Fri, 13 Apr 2007 08:18:23 -0400
> > >> From: Matthew Shepherd <mashephe@indiana.edu>
> > >> To: Elton Smith <elton@jlab.org>
> > >> Cc: Elke Aschenauer <elke@jlab.org>, Tim Whitlatch <whitey@jlab.org>,
> > >> Chuck Hutton <huttonc@jlab.org>, Alex Dzierba
> > >> <dzierba@indiana.edu>
> > >> Subject: Re: TOF/FCAL Supporting Documents
> > >>
> > >>
> > >> Hi Elton,
> > >>
> > >> I don't know off the top of my head whether or not mu-metal will be
> > >> enough for the ToF. Maybe Alex can comment more since he is more
> > >> familiar with the ToF design. As far as I know magnetic field tests
> > >> were done here at IU using mu metal and soft iron together -- none
> > >> were done with mu metal alone. I would assume this means there was
> > >> an expectation to use soft iron.
> > >>
> > >> To help with interference between tubes, the tubes could be placed at
> > >> an angle alternating back and forth every other bar. The soft iron
> > >> and mu metal would not have to go down to the scintillator -- it
> > >> would just need to protect the PMT area.
> > >>
> > >> Again, I understand your need and urgency for an actual mechanical
> > >> drawing to vet this design and explore potential interferences. For
> > >> the last 6 months we have had no one at IU capable of doing any
> > >> drawing or mechanical design. We are currently advertising and hope
> > >> to hire someone soon.
> > >>
> > >> -Matt
> > >>
> > >>
> > >> On Apr 13, 2007, at 7:33 AM, Elton Smith wrote:
> > >>
> > >>>
> > >>> HI Matt,
> > >>>
> > >>> Thanks for the documentation. We are trying to get top-level
> > >>> drawings for
> > >>> all the subsystems and in particular we want to have a more
> > >>> realistic
> > >>> sketch of the light guide/pmt assembly for the tof. Are the any
> > >>> space
> > >>> conflicts with stacking the pmt with mu-metal shields? We were
> > >>> concerned
> > >>> because we thought that soft iron shields might be necessary.
> > >>>
> > >>> Thanks, Elton.
> > >>>
> > >>> Elton Smith
> > >>> Jefferson Lab MS 12H5
> > >>> 12000 Jefferson Ave
> > >>> Suite # 16
> > >>> Newport News, VA 23606
> > >>> elton@jlab.org
> > >>> (757) 269-7625
> > >>>
> > >>> On Fri, 13 Apr 2007, Matthew Shepherd wrote:
> > >>>
> > >>>>
> > >>>> Hi Elke and Elton,
> > >>>>
> > >>>> Attached please find some supporting documents for TOF and FCAL
> > >>>> budget items.
> > >>>>
> > >>>> FCAL:
> > >>>>
> > >>>> - quote for fabrication of the PCB's for the CW bases
> > >>>> - quote for assembly of *electrical* portion of CW base
> > >>>> - quote for sheets of Sylgard for optical coupling of light
> > >>>> guides to
> > >>>> PMT
> > >>>>
> > >>>> On the last item: this quote is mainly proof of principle that
> > >>>> we can
> > >>>> get costs down to ~$1 per cookie. (In small quantities we paid $20
> > >>>> each so there was great concern as to whether or not using a
> > >>>> commercially manufactured cookie was even possible.) It gets
> > >>>> lumped
> > >>>> in with light guide costs in the budget. Sergey has estimated $20K
> > >>>> total to produce aluminized light pipes.
> > >>>>
> > >>>> TOF:
> > >>>>
> > >>>> - quote for XP2020 tubes, bases and mu metal shields
> > >>>> - quote for scintillator
> > >>>> - quote for cables
> > >>>>
> > >>>> -Matt
> > >>>>
> > >>>>
> > >>>>
> > >>>
> > >>
> > >>
> > >
> > > ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
> > > ) `\ -
> > > / '. | +
> > > | `, 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 -
> > > +=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-
> > > +=-+=-+
> > >
> >
> >
>
> ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
> ) `\ -
> / '. | +
> | `, 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 -
> +=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+
>
>