Re: FCal

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

On Sun, 27 Jan 2008, Mark M. Ito wrote:

Dear Mark,

yes, that is absolutely true, unfortnately buying lead tungsten is out of
our financial possibilities.

cheers elke


> Date: Sun, 27 Jan 2008 12:58:48 -0500
> From: Mark M. Ito <marki@jlab.org>
> To: whitey@jlab.org
> Cc: Elke-Caroline Aschenauer <elke@jlab.org>, halld-me@jlab.org
> Subject: Re: FCal
>
> Better to comment late than never. ;-)
>
> Using the lead tungstate gives a big improvement in photon energy
> resolution for PrimEx, from 5.4% in the lead glass to 2.5% in the lead
> tungstate at 1 GeV.
>
> whitey@jlab.org wrote:
> > Hi Elke,
> >
> >  The 3 main reasons for the support structure are to force the blocks
> > tight together so there is no gap between (tolerance can build up over 60
> > blocks across)and to hold the blocks in place against the force of the
> > cell wall against them (that keeps pressure on the cookie). Also, a
> > structure is needed to hold the TOF. We can probably still stagger and
> > keep the round shape.
> >
> > I will speak with Dave Kashey about this matter.
> >
> > Cheers,
> > Tim
> >
> >
> >> Dear Tim et al.,
> >>
> >> something to think about. On Saturday Curtis and I talked to the primex
> >> people and Ashot mentioned that the primes calorimeter is staggered with
> >> out supporting the lead-tungsten and lead glass blocks.
> >>
> >> The have quite some blocks and what i understood the calo weighs 8 tonnes.
> >> Mt question is why do we need a support structure for the FCal. Dave Kashy
> >> was involved in the design of the primex calorimeter, maybe we can talk to
> >> him ones on this issue.
> >>
> >> One reason why I'm asking is that there is the idea to reuse the Primex
> >> blocks for the inner part of the FCal. one thing is they are only 20x20
> >> mm^2 but the other issue is there might be an upgrade for the FCal to
> >> replace some of lead glass blocks with time with lead tungsten ones. so we
> >> would need a new cellular wall and so on and so on. Of course the
> >> staggering does not work for a round calorimeter, but do we need really a
> >> round one. Okay we have to think this over a bit.
> >>
> >> 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.:  001-757-269-6331                              -
> >>             +=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+
> >>
> >>
> >
> >
> >
>
>

 ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
  )    `\                                                  -
 /    '. |                                                  +
 |       `,              Elke-Caroline Aschenauer            =
  \,_  `-/                                                    -
  ,&&&&&V         Jefferson Lab                                +
 ,&&&&&&&&:       HALL-D 12C / F381       121-A Atlantic Avenue =
,&&&&&&&&&&;      Suite 8                 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.:  001-757-269-6331                              -
            +=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+