Difference between revisions of "GlueX TOF Meeting, February 18, 2011"

From GlueXWiki
Jump to: navigation, search
(notes as minutes)
m (Text replacement - "http://argus.phys.uregina.ca/cgi-bin/private" to "https://halldweb.jlab.org/doc-private")
 
(7 intermediate revisions by the same user not shown)
Line 12: Line 12:
 
# Prototype Status
 
# Prototype Status
 
# Contract Status
 
# Contract Status
−
# [http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=1705 TOF Schedule]
+
# [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=1705 TOF Schedule]
 
# Meeting time OK?
 
# Meeting time OK?
  
Line 33: Line 33:
 
==Slides==
 
==Slides==
  
−
Talks can be deposited in the directory <code>/group/halld/www/halldweb1/html/talks/2011-1Q</code> on the JLab CUE. This directory is accessible from the web at https://halldweb1.jlab.org/talks/2011-1Q/ .
+
Talks can be deposited in the directory <code>/group/halld/www/halldweb/html/talks/2011-1Q</code> on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2011-1Q/ .
  
 
=Minutes=
 
=Minutes=
  
−
TOF Meeting, 2/18
+
Present:
 +
* '''FSU''': Paul Eugenio
 +
* '''JLab''': Mark Ito (chair), Yi Qiang, Elton Smith, Sascha Somov, Simon Taylor, Tim Whitlatch, Beni Zihlmann
  
−
JLab: Mark, Tim, Sascha, Simon, Tim, Beni, Elton, Yi
+
==Minutes from the last meeting==
−
FSU:
+
  
−
Test says PMT is as advertised, better than intrinsic.  
+
We reviewed the [[GlueX TOF Meeting, January 21, 2011#Minutes|minutes from the meeting on January 21]].
  
−
Trip to SC to see Ralf
+
The '''Hamamatsu PMT arrived at JLab from FSU'''. Beni has been looking at it and has reported his findings in a [https://mailman.jlab.org/pipermail/halld-pid/2011-February/thread.html 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.
  
−
• good trip, with sasha
+
==Report from trip to the University of South Carolina==
−
• 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
+
Paul and Sasha Ostrovidov travelled to Columbia to visit Ralf Gothe and discuss his work on the forward time-of-flight for CLAS12. Some notes on their trip:
  
−
• making the counters wider may lose light
+
* Goals
−
• mounting pmt directly on scint like SC attractive
+
** compare and contrast design choices between USC and FSU
−
• has not finalized proposal yet
+
** identify factors limiting factors in resolution in the FSU set-up
−
• need to talk about it next time
+
** look at contradictory experiences with ESR wrapping at the two institutions
−
• outside diameter with mu metal 6 cm
+
* Ralf reviewed his construction and QA procedures with Paul and Sasha
−
• sc using 6 cm x 6cm counters
+
* time-walk corrections
−
• current design with steel tube more than adequate
+
** Sasha trying to fit all parameters at once
 +
** USC using an iterative approach, not letting all parameters float
 +
** without time walk corrections, USC resolution a factor of two worse
 +
** Elton: 1/sqrt(p.h.) may not be the right functional dependence
 +
* TDC's
 +
** resolution from electronics at FSU gives get something like the 55 ps value of the least significant bit
 +
** Ralf gets the same thing (lsb value) except in his case it is 25 ps from his CAEN device
 +
** Why not go to CAEN TDC?
 +
*** Paul will get from a loaner from Mark Kibilko
 +
*** readout protocol should be OK for GlueX pipelined DAQ
 +
* PMT choices
 +
** USC using 8-stage, not the 10-stage, Hamamatsu PMT
 +
** 10-stage tube perhaps not available when they made the decision
 +
* ESR
 +
** improved light collection: results from FSU
 +
** SC had poorer performance with ESR
 +
** material USC was ESR: looks like white Tedlar, not specular
 +
** Ralf had some mylar that he could not use for his counters, gave it to Paul
 +
* Tour of USC lab
 +
** saw alignment devices
 +
** saw glueing tools, jigs
 +
* Contract
 +
** Paul got a copy of the assembly and testing document from Ralf that was part of USC's 12-GeV contract with JLab.
  
 +
==Geometry==
  
−
schedule
+
Elton reminded us of the issue of the geometry of the TOF counters that has been discussed previously. Some notes from the discussion:
−
• 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
+
  
 +
* making the counters wider may lose light
 +
* mounting PMT directly on the scintillator like USC is doing is attractive
 +
* Paul has not finalized a proposal yet
 +
* need to talk about it at the next meeting
 +
* outside diameter with mu-metal 6 cm
 +
* USC using 6 cm x 6 cm counters
 +
* current GlueX design with steel tube more than adequate for magnetic shielding
  
−
mu metal shield will be tested
+
==Schedule==
  
−
rates for innermost paddles near the beam hole: how do we address that
+
Tim walked us through the [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=1705 schedule in the current project plan]. Again some notes:
  
 +
* PMT's are the kind of thing JLab would buy, scintillator as well
 +
* other items would likely be bought by FSU
 +
* contract has to be awarded before PO goes out, say 7 months from now
  
 +
The overall message is that decision making on the TOF will have start now to make this schedule.
  
 +
==Other items==
  
−
 
+
* Tim will test the mu-metal shield that came on the Hamamatsu tube that Beni has been looking at.
−
get drawing from tim on
+
* Elton reminded us that rates for inner-most paddles near the beam hole are problematic. We need to decide how to address that.

Latest revision as of 17:14, 24 February 2017

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

Telephone

  1. dial:
  2. enter access code followed by the # sign: 3421244#

Slides

Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2011-1Q on the JLab CUE. This directory is accessible from the web at https://halldweb.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. Some notes on their trip:

  • Goals
    • compare and contrast design choices between USC and FSU
    • identify factors limiting factors in resolution in the FSU set-up
    • look at contradictory experiences with ESR wrapping at the two institutions
  • Ralf reviewed his construction and QA procedures with Paul and Sasha
  • time-walk corrections
    • Sasha trying to fit all parameters at once
    • USC using an iterative approach, not letting all parameters float
    • without time walk corrections, USC resolution a factor of two worse
    • Elton: 1/sqrt(p.h.) may not be the right functional dependence
  • TDC's
    • resolution from electronics at FSU gives get something like the 55 ps value of the least significant bit
    • Ralf gets the same thing (lsb value) except in his case it is 25 ps from his CAEN device
    • Why not go to CAEN TDC?
      • Paul will get from a loaner from Mark Kibilko
      • readout protocol should be OK for GlueX pipelined DAQ
  • PMT choices
    • USC using 8-stage, not the 10-stage, Hamamatsu PMT
    • 10-stage tube perhaps not available when they made the decision
  • ESR
    • improved light collection: results from FSU
    • SC had poorer performance with ESR
    • material USC was ESR: looks like white Tedlar, not specular
    • Ralf had some mylar that he could not use for his counters, gave it to Paul
  • Tour of USC lab
    • saw alignment devices
    • saw glueing tools, jigs
  • Contract
    • Paul got a copy of the assembly and testing document from Ralf that was part of USC's 12-GeV contract with JLab.

Geometry

Elton reminded us of the issue of the geometry of the TOF counters that has been discussed previously. Some notes from the discussion:

  • making the counters wider may lose light
  • mounting PMT directly on the scintillator like USC is doing is attractive
  • Paul has not finalized a proposal yet
  • need to talk about it at the next meeting
  • outside diameter with mu-metal 6 cm
  • USC using 6 cm x 6 cm counters
  • current GlueX design with steel tube more than adequate for magnetic shielding

Schedule

Tim walked us through the schedule in the current project plan. Again some notes:

  • PMT's are the kind of thing JLab would buy, scintillator as well
  • other items would likely be bought by FSU
  • contract has to be awarded before PO goes out, say 7 months from now

The overall message is that decision making on the TOF will have start now to make this schedule.

Other items

  • Tim will test the mu-metal shield that came on the Hamamatsu tube that Beni has been looking at.
  • Elton reminded us that rates for inner-most paddles near the beam hole are problematic. We need to decide how to address that.
Retrieved from "https://halldweb1.jlab.org/wiki/index.php?title=GlueX_TOF_Meeting,_February_18,_2011&oldid=80959"