[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Cal Working Group Meeting Notes July 7




See Wiki

=Minutes=
Participants: JLab: Fernando, Tim, Elke, Elton, Beni, Sasha; UofR: Zisis,
Andrei; IU: Matt.

 Preparations for Lehman Review
# [[Alternative readout]] (See also DRAFT
[http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=1077
GlueX-doc-1077])
#* Elton reviewed the draft document and results of light collection for
various light guide configurations.
#* Brief summary off efficiencies: Square SiPM eff~91%, Trapezoid SiPM
eff~81%, Inner FM inclined eff~64%, Outer FM inclined eff~70%, Inner FM
straight upstream eff~62%.
#* Matt noted that Elton should look at their light collection studies for
realistic parameters
[http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=1077
GlueX-doc-1045].
# Dependence of resolution on granularity
[http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=659
GlueX-doc-659]
#* All studies were for normal incidence.
#* Elton asked if anyone understood the (large) dependence of delta_z on
the number of layers. Matt indicated that fits to the multiple layers and
position determination may not have been used in these studies. In any
case, the optimal algorithms to obtain delta_z is not yet developed.
#* Elke has done a cost comparison between the FM and SiPM options, and is
about $360K more expensive, taking into account fewer electronic channels
but increased cost per light detector.
# BCAL Geometry specifications, see Figure 3 of
[http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=922
GlueX-doc-922]
#* Note that proposed solution for covering end of the Bcsl in
GlueX-doc-922 is different than in GlueX-doc-1077, and tradeoffs between
ease of fabrication and light collection need to be completed. These
should be added to the Action Item tracker.
#* Zisis: The increased granularity for the fine mesh (FM) option is
reviewed, saturation of tubes should also be considered.
# BCAL Number of optical photons, see pages 4-7 of
[http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=808
GlueX-doc-808]
# Pi0 and eta mass resolution [[Media:Pi0eta mass resol.png | Physics and
Calorimeter Performance Metrics Fig. 10]]
# Reconstruction work is pending -- see 3D-rendering of geometries in the
links below.
#* See [[Media:bcal_4x6.pdf| BCAL 4x6 readout]], [[Media:bcal_3x3.pdf|
BCAL 3x3 readout]], [[Media:det_cabling.pdf| BCAL, CDC, FDC cables]],
[[Media:bcal_cdc_gap.pdf| Gap between BCAL and CDC]]
#* New geometries are implemeted in new xml files which will be checked
into svn but with designated names.
#* Elke emphasized that some of the changes willl update the geometry to
our "nominal" design, such as rerouting cables upstream. Other changes,
such as various configurations for the FM pmts are alternative
configurations for study only at this point. These types of changes should
be kept separately so the updates to the nominal design become part of the
base design, while the others are kept as study options.
#* Matt: asked if any checks have been made to see if the hits are
correctly propagated through the code. (Beni: no, but will check). Also
with new granularities, the reconstruction will be incorrect and new
algorithms implemented to match the changed geometry.
#* Beni will make the new geometry files  available to IU for
reconstruction studies. Blake will start these studies this week with the
help of Mihajlo and Matt.
#* Sasha asked if addtional help is needed. For now, the plan is for IU to
complete the photon reconstruction studies.

 Updates
# Calibration system
#* Zisis update for Christina: Studies are waiting for difusers. The goals
and requirements for a common calibration system for all pmt based systems
is not been defined. We decided that we need to dedicate a working group
meeting to this topic. In preparations we need to put write down the main
goals and common features (e.g. relative gain changes, stability tests,
how to include TOF, start counter?, etc.)
# FCAL
#* Setup for studying light collection in Pb glass is being updated. New
fast pulsed blue LED (sub-ns rise time) is implemented. First tests with
PRIMEX type coupling shows that measurements with cookies are comparable
to those with greased joints (used for previous tests).
#* Building a 3x3 array of blocks and dark box so that more than one block
can be tested at a time. Readout will be with Flash ADC to continue to
develop timing algorithms.
# BCAL
#* A20AH 3x3m2 arrays. Calibration of system at low rate (1KHz) underway.
Other measurements will also be performed at +2V and +4V above breakdown.
(Previous measurements were at +3V).
# Preparations for fiber testing
#* Elton reminded that the fiber procurement is out and we expect
responses by Aug 1. The specification for absolute light output still
needs to be checked with fibers in hand. We also need operational setups
for testing and qualifying "standard" fibers when they are delivered from
the chosen manufacturer.
#* Zisis indicated that the response in terms of number of photoelectrons
to a 90Sr source will be tried toward the end of July.
#* Beni: The setup at JLab is underway. The DAQ is operational, but
waiting on other parts. Expect receipt by beginning of Aug.
# SiPM
#* Preparation of document summarizing UofR and JLab measurements in
preparation for presentation at the next SiPM phone conference (July 15).
#* Fernando is reviewing the circuit for the TIA boards for feedback next
Tuesday as well.


Elton Smith
Jefferson Lab MS 12H5
12000 Jefferson Ave
Suite # 16
Newport News, VA 23606
elton@jlab.org
(757) 269-7625
(757) 269-6331 fax