Difference between revisions of "JEF meeting Aug 31, 2015"

From GlueXWiki
Jump to: navigation, search
(Minutes)
(Minutes)
 
(2 intermediate revisions by the same user not shown)
Line 26: Line 26:
 
=Minutes=
 
=Minutes=
 
Attendees: J. Feng, L. Gan., B. Karki, D. Mack, A. Somov, S. Taylor, J. Stevens
 
Attendees: J. Feng, L. Gan., B. Karki, D. Mack, A. Somov, S. Taylor, J. Stevens
*Dave gave a report about his toy monte-carlo studies of proton/kaon/pion separation using time-of-flight
+
*Dave gave a report about his toy monte-carlo studies of proton/kaon/pion separation using time-of-flight with the GlueX detector
 
** Using a nominal 100 ps timing resolution and 3% momentum resolution for forward-tracks, expect e-/π separation below ~1 GeV/c, π/K separation below ~3 GeV/c, K/proton separation below ~6 GeV/c
 
** Using a nominal 100 ps timing resolution and 3% momentum resolution for forward-tracks, expect e-/π separation below ~1 GeV/c, π/K separation below ~3 GeV/c, K/proton separation below ~6 GeV/c
 
** Looked at mass distributions computed using p and beta -- maybe not ideal for using in a confidence-level analysis because of non-Gaussian tails
 
** Looked at mass distributions computed using p and beta -- maybe not ideal for using in a confidence-level analysis because of non-Gaussian tails
Line 34: Line 34:
 
** Expand survey to include 2π0, 3π0, etc.?  
 
** Expand survey to include 2π0, 3π0, etc.?  
 
** Focus on channels that might lead to the first papers from the commissioning data?
 
** Focus on channels that might lead to the first papers from the commissioning data?
*** Exclusive π0 production, looking at Σ beam symmetry?
+
*** Exclusive π0 production, looking at Σ beam asymmetry?
 
*** η production cross section?
 
*** η production cross section?
 
** Consensus was to continue the 2γ work started by Bishnu and Justin, focussing on asymmetries/angular distributions while we work out the details of normalization.
 
** Consensus was to continue the 2γ work started by Bishnu and Justin, focussing on asymmetries/angular distributions while we work out the details of normalization.
 
*Sascha reported that pieces are starting to come together for magnetic shielding studies (Hall probe, a Helmholtz coil is available, perhaps a permanent magnet?).  Jing and Sascha will start working on setting up for measurements next week.
 
*Sascha reported that pieces are starting to come together for magnetic shielding studies (Hall probe, a Helmholtz coil is available, perhaps a permanent magnet?).  Jing and Sascha will start working on setting up for measurements next week.
 
In particular we need to determine how many layers of mu-metal will be needed and whether we need a soft-iron outer layer as well.
 
In particular we need to determine how many layers of mu-metal will be needed and whether we need a soft-iron outer layer as well.
 +
*Sascha lead a discussion regarding PMTs for the insert crystals
 +
** Peak anode current needs to be considered carefully -- non-linearity? Need to do some work on divider design.
 +
** Hamamatsu have another PMT (other than the round-face model we have been considering) with a square face (2.3x2.3 cm^2) that can handle higher peak current
 +
** Hammatsu have cheaper (but with worse performance) round-face PMTs than the ones we've been considering.

Latest revision as of 16:24, 3 September 2015

Meeting time and location= 13:30 EST (JLab time) CC F326-327

=Connection instructions=

We are using BlueJeans Video/Audio conferencing. Our meeting ID number is 370588741. Click "Expand" for more details.

  • Make sure you have created a BlueJeans account via your JLab CUE account using this link:
  • If connecting via Web Browser: click this link (no passcode is needed):
  • If connecting via Phone: Dial one of the following numbers and then enter the meeting ID above and hit "#" or "##"
  • If connecting via Polycom unit:
    • Dial 199.48.152.152 or bjn.vc
    • Enter meeting ID above

Agenda

Minutes

Attendees: J. Feng, L. Gan., B. Karki, D. Mack, A. Somov, S. Taylor, J. Stevens

  • Dave gave a report about his toy monte-carlo studies of proton/kaon/pion separation using time-of-flight with the GlueX detector
    • Using a nominal 100 ps timing resolution and 3% momentum resolution for forward-tracks, expect e-/π separation below ~1 GeV/c, π/K separation below ~3 GeV/c, K/proton separation below ~6 GeV/c
    • Looked at mass distributions computed using p and beta -- maybe not ideal for using in a confidence-level analysis because of non-Gaussian tails
    • Some understanding of ghost bands seen in PID plots from real data = wrong beam bucket
      • Biggest impact is for kaon id
  • We discussed what the next step in the survey of neutral final states started by Bishnu and Justin (looking at final states with 2 photons)
    • Expand survey to include 2π0, 3π0, etc.?
    • Focus on channels that might lead to the first papers from the commissioning data?
      • Exclusive π0 production, looking at Σ beam asymmetry?
      • η production cross section?
    • Consensus was to continue the 2γ work started by Bishnu and Justin, focussing on asymmetries/angular distributions while we work out the details of normalization.
  • Sascha reported that pieces are starting to come together for magnetic shielding studies (Hall probe, a Helmholtz coil is available, perhaps a permanent magnet?). Jing and Sascha will start working on setting up for measurements next week.

In particular we need to determine how many layers of mu-metal will be needed and whether we need a soft-iron outer layer as well.

  • Sascha lead a discussion regarding PMTs for the insert crystals
    • Peak anode current needs to be considered carefully -- non-linearity? Need to do some work on divider design.
    • Hamamatsu have another PMT (other than the round-face model we have been considering) with a square face (2.3x2.3 cm^2) that can handle higher peak current
    • Hammatsu have cheaper (but with worse performance) round-face PMTs than the ones we've been considering.