Re: list of assignments for bcal decision

["George Lolos" <George.Lolos@uregina.ca>]

Hi Elton:

I did not have time yet to look at your posting, I will do later today. 
I assume you didn't have time to read the draft I sent you yesterday. 
We can address those on Monday.

The threshold of 20 MeV, needs to be investigated particularly so in
terms of the approximate 2 radiation lengths of cables from the
chambers.  In  my report, I explicitly mention the 20 MeV threshold in
terms of the energy deposition in the SciFi's (~2.4 MeV) and the
resulting numbers of P.E.'s in the SiPM's.

I agree that SensL will not take part in our discussions and I don't
think they would do this even if we asked them to.  I also think that
the opportunity for us as a group to invite them to attend a specific
session, the emphasis is on the invitation and specific session, is
invaluable for the rest of the working group to hear first hand where
they are in terms of the R&D and further progress, costs and everything
we feel it's important for us to know. We therefore have to decide among
us on Monday when is the optimal time for such session and communicate
this to SensL.  I would think that the second session on Monday morning
may be a good time, we would have the first session to get the questions
together and look at the road map.  Elke's suggestion for the afternoon
on Monday is also a good alternative, if their travel plans allow it.

George

>>> Elton Smith <elton@jlab.org> 04/13/07 8:10 AM >>>

HI George,

I have posted an update to the note on specifications and evaluation of
readout options (GlueX-doc-795). Before you get too excited: this is
just
a draft and I am trying to prepare a framework for evaluating various
options. The numbers I have included need to checked and we need to
discuss whether my logic is appropriate. These issues also need to be
considered along with the information you are putting together.

One particular issue that I became aware of is that many of the
requirements are driven by conditions at the nominal threshold of 20
MeV.
We can discuss the implications of this requirement on Monday at our
phone
conference.

We also need to think about an goals and agenda for the workshop Apr
23-24. It appears that we will have visitors from SensL, but I do not
think they should participate in all our discussions, although their
input
would be very valuable. Elke has suggested to meet with them on Monday
afternoon after we have had some time for internal discussions in the
morning. We also need to schedule video conference sessions where others
can participate remotely (e.g. Christina and Richard + others).

Cheers, Elton.


>                                          Christine
> > HI George,
> >
> > See below:
> >
> >
> > On Wed, 11 Apr 2007, George Lolos wrote:
> >
> >> Hi Elton:
> >>
> >> A couple of comments with regards to your e-mail below:
> >>
> >> 1. The review (teleconference I presume) next Monday is a good idea
and
> >> we will participate from Regina.
> >
> > We are planning for 1:00 pm on Monday.
> >
> > To connect by telephone:
> >
> > 1.) dial:
> >  800-377-8846 : US
> >  888-276-7715 : Canada
> >  302-709-8424 : International
> >
> > 2.) enter participant code: 39527048#  (remember the "#")
> >
> >>
> >> 2. I thought that the meeting on the 23rd is not to make any
decision
> >> regarding the BCAL read-out, but instead we will discuss in great
> >> technical details the various options (SiPM's, Planacons and mesh
> >> PMT's).  Yet you refer to a decision that gets my blood flowing.
> >> Anything changed or it was a Freudian slip? :-)
> >>
> > What we present at the Lehman review this June and how this is
presented
> > must definitely be decided. We are already turning in budget
estimates
> > based on assumptions of the readout, and we need to be able to back
them
> > up with quantitative arguments.
> >
> > In addition need to satisfy one of our internal milestones for FY07
which
> > is a "decision on the readout for the barrel calorimeter." This was
> > presented at the last Lehman review and is also shown as slide #6 in
the
> > manpower and budget presentation that Elke showed the collaboration
less
> > than two weeks ago (see
/group/halld/INFO-FOR-COLLAB/Budget_manpower.ppt)
> >
> > Also, the deadline for the following Recommendation #27 IPR (2005)
Sec 2.5
> > is June 2007:
> >
> > "Develop a plan for readout of GlueX barrel calorimeter based upon
> > conventional photomultiplier tubes.  The plan should include fiber
> > routing, end iron configuration, shielding, and cost estimate."
> >
> > So, yes, decisions need to be made. Are they final? No, but the
longer we
> > wait the harder they are to change, and we must make our best effort
to
> > make the best and most informed decisions possible.
> >
> >> 3. I have received notification from SensL that a couple of their
people
> >> will be able to visit JLab next week and perhaps be able to take
part in
> >> some of the discussions on the April 23-24.  I would strongly
encourage
> >> this possibility to hear from the source directly the update and be
able
> >> to ask all the specific questions we need.  This partly addresses
your
> >> suggestion of persons outside the project.  What other names do you
have
> >> in mind and what is their role or expertise?  Meetings that have
too
> >> many persons involved get cumbersome and not as productive as
smaller
> >> groups of persons directly in the know.  On the other hand, we
don't
> >> want to exclude anyone with specific knowledge on field resistant
> >> sensors and electronics expertise.  Please, don't invite Domingo
and
> >> others just for an audience and ideas on the fly.
> >>
> > We have not heard anything about anyone from SensL visiting JLab,
and we
> > want to make sure that their time he is productive. So they should
let us
> > their schedule ASAP. Depending on who is coming and their expertise
> > (technical? sales?), it may or not be appropriate for them to
participate
> > in our discussions.
> >
> > One of the single most important numbers we need from them (an
informal
> > budgetary estimate is fine, but needs to written down) is the cost
per
> > channel of SiPMs in production (including all auxiliary
> > mounting/electronics/etc that would be necessary for a particular
> > configuration).
> >
> >> 4. Before Zisis and George commit themselves to yet another
document,
> >> please have a look at 739, 708 and 664 (all by Zisis) and see if
the
> >> info is not already there.  I am also working on a detailed report
> >> showing BCAL response to photons, spectra and read-out segmentation
and
> >> how it matches the SiPM parameters.  Manpower at the UofR is so
tight
> >> now, any duplication of effort on material already readily
available
> >> will only make things worse on other fronts.
> >>
> > I hear you. I will try to collect together the necessary info.
> >
> >> The topics you listed look fine to me.
> >>
> >> So sprach Georg
> >>
> >> George
> >>
> >>
> >>
> >> >>> Elton Smith <elton@jlab.org> 04/11/07 6:04 AM >>>
> >>
> >> Hi Bcal enthusiasts,
> >>
> >> I would like to reserve an hour on Monday afternoon (I suggest 1:00
pm)
> >> to
> >> review issues that need addressing before the Bcal decision meeting
the
> >> following week. Below is a list of issues that need updates. I have
put
> >> some names down on the likely candidates for reporting on these.
> >>
> >> It might also be useful to go over the format/schedule for the Bcal
> >> review
> >> (times, format, etc). Do we want to ask a couple of persons which
are
> >> not
> >> direcly in the project to give us some feedback?
> >>
> >> I would also ask George/Zisis to prepare a 1-2 page table of Bcal
design
> >> parameters in a format similar to what was done for the drift
chambers
> >> before the DC review (See for example GlueX-doc-740). We will need
this
> >> for all subsystems in preparation for CD-2, so this is a good time
to
> >> create it for the Bcal. (This information is in various documents
and it
> >> will be useful to summarize it into a couple of pages).
> >>
> >> Topics (please send me items that are missing)
> >>
> >> 0.  How to summarize how physics needs drive the design specs
> >>         - energy resolution
> >>         - energy threshold
> >>
> >> 1.  SiPM
> >> 	- linearity/dynamic range
> >> 	  - need for amplification
> >> 	- need for cooling?
> >>           - measurements of dark rate (Carl)
> >>           - spectrum of dark noise (Carl)
> >> 	- lifetime (DESY experience) (George)
> >>         - outline of single electronics channel
(LV/disc/signal/etc)
> >>           (George/Zisis)
> >> 	- budgetary estimate from SensL
> >>
> >> 2.  Planacon
> >> 	- amplifier/shaper (Carl/Vladimir?)
> >> 	- light guide design / optics of light collection of WC into
> >>           fibers (George?)
> >> 	- placement
> >>           - B-field map of fringe field (David)
> >> 	- lifetime
> >>         - measurements of dark rate (Carl)
> >>
> >> 3.  Wire Mesh
> >>         - use in combination with SiPMs?
> >>
> >> --
> >>
> >>
> >
> >
>
>
>