may 20-22 2004 status of fcal issues to be addressed at the detector review
TRANSCRIPT
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Status of FCAL
Issues to be addressed at the detector review
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Major Issues
• Suitability of the technology• Alternative technologies• Magnetic shielding issues• Is the existing glass radiation damaged?• Do the existing phototubes still work?• Integration• Schedule and budget
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Suitability of the technology
• Existence proof: E852, a spectroscopy experiment at approximately the same energy, PWA is possible with data taken by that experiment. Many examples of spectra exist and have been previously shown
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Alternative technologies
• Other technologies will work, among them CsI (like KTeV), perhaps NaI (like CB)
• Involves starting from scratch, minimum cost exceeds $15M.
• Production schedule is an issue, manufacturers are currently booked up.
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Magnetic shielding issues
• Precise determination of the fringe field remains to be made, estimates go as high as 200 gauss at the plane of the photocathodes
• Simulations of the field with the cellular wall in place indicate shielding is possible with soft iron/mu-metal
• Possibility of reducing the fringe field with flux return iron exists and will work
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Is the existing glass radiation damaged?
• Yes, some of it. The ~600 blocks used for Jlab experiment RadPhi are visibly damaged but in such a way as to have a minimal effect on resolution. Preliminary measurements have been made and are proceeding. Curing is also possible.
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An end view of 3 blocks
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The self shielding effect
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The UV curing oven. 900 watt, 50% duty cycle, 2hr max on time
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Do the existing phototubes still work?
• Very preliminary measurements indicate that they do still work.
• Experience with this particular type of tube indicated a lifetime of at least 25 years.
• If needed, replacements can be manufactured.
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Integration issues
• Detector is “last in”, is on rails.• Self contained design, simple
connection to outside world. (Power, data readout, perhaps cooling water and fire suppression)
• Frame must support the ToF hodoscope and the Cerenkov detector. Both low mass devices, mechanically straightforward.
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Schedule & Budget
• Schedule bottleneck: Electronics manufacturing, problem is solvable requires additional manpower
• Budget bottleneck: CDn, authorization of construction start.
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Activity NameSecond Q Third Q Fourth Q First Q Second Q Third Q Fourth Q First Q Second Q Third Q Fourth Q First Q Second Q Third Q Fourth Q First Q Second Q Third Q Fourth Q First Q Second Q Third Q Fourth Q First Q Second Q Third Q
2004 2005 2006 2007 2008 2009 2010
Second Q Third Q Fourth Q First Q Second Q Third Q Fourth Q First Q Second Q Third Q Fourth Q First Q Second Q Third Q Fourth Q First Q Second Q Third Q Fourth Q First Q Second Q Third Q Fourth Q First Q Second Q Third Q
LGD
PMT evaluation 7/1/04 7/1
Block evaluation 4/1/04 1/1
New frame 1/1/05 7/1
Cellular wall 7/1/05 1/1
Monitoring system 1/1/05 1/1
TOF
Evaluate scintillator 1/1/06 1/1
Evaluate PMT's 1/1/06 1/1
Frame 1/1/07 1/1
Monitoring system 1/1/07 1/1
Cockcroft-Walton
BasesConstruct 100 prototype
bases
4/1/04 10/1
Long-term tests 7/1/04 4/1
Production 1/1/06 1/1
FADCSConstruct prototype 4/1/04 7/1
Testing 7/1/04 1/1
Production 1/1/06 1/1