There are 3 types of mixings: air gap, polygonal cookie, and plastic window. One should avoid edges of photocathod. Little acrillic window reasonably thick between end of fibers and PMT photocathod should do the job. There is an issue of vacuum seal. Don suggested ultrasonic sealing technology.
Tests on systematics of 10x12 cm prototype measurements (in progress). The idea is to measure same piece 10 times and see the repeatablility of the results. We have also be more systematic in organizing results.
Don presented samples from Elgen Technology (Texas) EJ-204, EJ-204A. Cost is about $400 per plate. It is cheaper than Bicron, but not much cheaper. The samples are cast PVT. There will be sample measurement.
There is an effort to make molded scintillator sample in Bocron (Don). We have one sample BC-412 from them which is old, and we want to measure it.
Full test of KTeV vacuum system are going to be performed soon.
How to develop aging criteria for scintillator. Anna is looking into that. There is a piece of BC-404 which was sitting for 3 years in a box. There are KTeV samples as well. PHENIX sample can be tested as well.
Measurement of low energy inefficiency, that should be done in Protvino on radioactive source.
Estimate rad dose for CKM forward Veto system and check radiation damage that would be done to KTeV CsI detector.
We need to put more effort into design of BIVS. We need to talk to Troitsk.
What kind of readout. There will be TDC, ADC in CAMAC. There is also PCI card that we need to readout. There is also QIE card (It may be PCI or CAMAC - Bob will try to settle the choice). Check how this setup look in other prototypes. How the drivers are written.
We need to understand rates in JLab and what are requirements for DAQ. We should try to use Linux system and test if it can do 100Hz. We need someone in charge of this project.
QIE gain issue. It is too sensitive so we need to run the PMT at lower voltage which can mean someld inefficiency. Or may be there is another solution.
Low energy inefficiency study on plutonium sorce is a priority. Also producing scintillator samples. We need to understand from Soldatov when he cna produce molded piece. It better be done in the summer.
Scheduling. There are several runs scheduled. It is not clear when our test is going to be. Perhaps in October.
Erik presented another approach to staggering of alternating pieces (pieces should overlap to avoid cracks). Instead of few mm shifts, he proposed 1/2 of tile shifts. It minimizes fiber routing. It can improve phi resolution. It may make energy calibration more complicated. But there are going to be more phototypes firing. So you average rate will be higher and dead time is an issue. Regardles from the choice of layout we are not going to use it in prototype. Studies are needed.