Revision as of 12:45, 22 February 2011

Location, Time

Friday, February 18, 2011
2:00 pm EST
JLab: CEBAF Center, Room F326/7

Agenda

1. Announcements
2. Minutes from the last meeting
3. Report from trip to U. of South Carolina: Paul
4. Prototype Status
5. Contract Status
6. TOF Schedule
7. Meeting time OK?

Communication

Videoconference

1. ESNet: 8542553
2. EVO: EVO site
   • direct meeting link
   • Phone Bridge ID: 6 9368

Telephone

1. dial:
   • US and Canada: (866)740-1260 (toll free)
   • International: (303)248-0285 (toll call) or look up toll-free number at http://www.readytalk.com/intl
2. enter access code followed by the # sign: 3421244#

Slides

Talks can be deposited in the directory /group/halld/www/halldweb1/html/talks/2011-1Q on the JLab CUE. This directory is accessible from the web at https://halldweb1.jlab.org/talks/2011-1Q/ .

Minutes

Present:

• FSU: Paul Eugenio
• JLab: Mark Ito (chair), Yi Qiang, Elton Smith, Sascha Somov, Simon Taylor, Tim Whitlatch, Beni Zihlmann

Minutes from the last meeting

We reviewed the minutes from the meeting on January 21.

The Hamamatsu PMT arrived at JLab from FSU. Beni has been looking at it and has reported his findings in a series of email messages to the PID list. He concludes that the tube performs as advertised and its contribution to timing resolution is small compared to other factors, as well as compared to our spec for the TOF.

Report from trip to the University of South Carolina

Paul and Sasha Ostrovidov travelled to Columbia to visit Ralf Gothe and discuss his work on the forward time-of-flight for CLAS12.

• good trip, with sasha • goals ∘ on design choices, compare and contrast ∘ resolution not at goal ∘ ESR beneficial or not • went over their procedures • time-walk corrections ∘ sasha trying to fit all parameters at once ∘ sc using iterative approach, not letting all parameters float ∘ without time walk corrections, factor of two worse ∘ Elton 1/sqrt(ph) not the right functional dependence ∘ laser might have different spectral response • TDC's ∘ resolution from electronics get something like 55 ps, the least significant bit ∘ Ralf gets the same thing, lsb value, except 25 ps from his CAEN device ∘ Why not go to CAEN TDC. ∘ will get from Mark Kibilko ∘ readout protocol should be OK • PMT choices ∘ SC using 8 stage, not the 10 stage ∘ 10 stage tube perhaps not available • ESR ∘ improved light collection results from FSU ∘ SC had poorer performance with ESR ∘ material they were calling ESR, looks like white Tedlar, not specular ∘ Ralf had mylar that he could not use and gave it to Paul • tour of lab ∘ alignment devices ∘ glueing tools, jigs • Contract ∘ assembly and testing document

Geometry

• making the counters wider may lose light • mounting pmt directly on scint like SC attractive • has not finalized proposal yet • need to talk about it next time • outside diameter with mu metal 6 cm • sc using 6 cm x 6cm counters • current design with steel tube more than adequate

schedule • tim shows one • pmt kind of thing JLab would buy • scint as well • others bought by FSU • contract has to be awarded PO goes out, 7 months from now

mu metal shield will be tested

rates for innermost paddles near the beam hole: how do we address that

get drawing from tim on