May 20-22 2004 Status of FCAL Issues to be addressed at the detector review

May 20-22 2004 QuickTimeª and aTIFF (Uncompressed) decompressorare needed to see this picture.

Status of FCAL

Issues to be addressed at the detector review


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


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


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.


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


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.


An end view of 3 blocks


The self shielding effect



The UV curing oven. 900 watt, 50% duty cycle, 2hr max on time


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.


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.


Schedule & Budget

• Schedule bottleneck: Electronics manufacturing, problem is solvable requires additional manpower

• Budget bottleneck: CDn, authorization of construction start.


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

Documents

May 20-22 2004 Status of FCAL Issues to be addressed at the detector review