[Halld-cpp] CPP meeting minutes

Thu Jul 14 14:11:15 EDT 2016

Hi Dave,

Thanks for posting the minutes. It is an effort to do this but it is 
nice to have a record of the discussions.

Cheers, Elton.

On 7/14/16 12:16 PM, David Lawrence wrote:
> Hi All,
>
>   Some minutes from this morning’s CPP meeting have been posted at the 
> following link and copied below.
>
> https://halldweb.jlab.org/wiki/index.php/%CE%A0_polarizability_Meeting_July_14,_2016
>
> Regards,
> -David
>
>
>   Minutes[edit
>   <https://halldweb.jlab.org/wiki/index.php?title=%CE%A0_polarizability_Meeting_July_14,_2016&action=edit&section=5>]
>
> Attendees: Rory M., Bobby J., Andrew S., Matt D., David L., Elton S., 
> Tim W.
>
>
>     FCAL Platform[edit
>     <https://halldweb.jlab.org/wiki/index.php?title=%CE%A0_polarizability_Meeting_July_14,_2016&action=edit&section=6>]
>
>   * PrimEx η requires a calorimeter on the FCAL platform as well for
>     continuous calibration via Compton scattering events
>       o They have a readiness review coming up next Wednesday where a
>         preferred and contingency solution are expected to be presented
>       o Both solutions require use of the same space the FMWPC is
>         expected to occupy
>   * FCAL platform will need modifications:
>      1. Move electronics racks further apart
>      2. Enhanced structural support for FMWPC and large iron absorbers
>   * Desirable to place FMWPC as close to FCAL as possible while still
>     allowing access to FCAL dark room
>   * Current FMWPC design has 8 chambers that are:
>       o 64"x64" x 2"
>       o Made of Al hexcell w/ flat faces
>       o Roughly 200 lbs each (Tim noted JLab guidelines limit human
>         lifting to 50lbs)
>       o Iron absorbers 20cm thick
>           + Iron absorbers may be round to minimize material and match
>             FCAL geometry
>           + Shape driven more by engineering concerns than physics
>   * We will need to move 1 full crate of fADC125 electronics to
>     platform for FMWPC
>       o Need two 72 channel modules per MWPC chamber (16 modules total)
>       o (Plan is to borrow from CDC)
>
>
>       Schedule[edit
>       <https://halldweb.jlab.org/wiki/index.php?title=%CE%A0_polarizability_Meeting_July_14,_2016&action=edit&section=7>]
>
>   * Approved experiments are now required to go through a readiness
>     review in advance of getting scheduled to run
>   * Elton suggested and there was consensus that we should aim for
>     having a Readiness Review for CPP approximately 1 year for now
>   * Tim will try and estimate how long it will take to do a complete
>     design of the FCAL modifications
>       o Final design parameters are not currently available so final
>         engineering can't be done until we provide those
>       o Elton suggested we start drafting a design spec. before
>         meeting again with Tim in a couple of months
>   * Need to keep TOF, FCAL folks in loop since rack movements require
>     rerouting some cables which will require their involvement
>
>
>     fADC125 Test setup at UMass[edit
>     <https://halldweb.jlab.org/wiki/index.php?title=%CE%A0_polarizability_Meeting_July_14,_2016&action=edit&section=8>]
>
>   * Andrew reported that test stand now appears to be ignoring
>     lookback setting
>   * No known changes to configuration or software
>   * Suggested that they try different set of channels which connect to
>     different 1st stage FPGA
>       o Requires changes to Read-out-list (ROL) as well as moving plug
>         on front panel
>   * Andrew will work on this and consult with David as needed
>   * If this doesn't work then module will need to be sent back to JLab
>     for testing/repair
>
>
>     MWPC transport Cart[edit
>     <https://halldweb.jlab.org/wiki/index.php?title=%CE%A0_polarizability_Meeting_July_14,_2016&action=edit&section=9>]
>
>   * Matt presented latest version of transport cart design
>   * Modified slightly from last time:
>       o Reinforced for greater strength/rigidity
>       o Shorted brace bars to relax tolerance
>   * Will measure clearance from floor for electronics etc. and then
>     create parts list in order to proceed with procurement
>
>
>     Electronics[edit
>     <https://halldweb.jlab.org/wiki/index.php?title=%CE%A0_polarizability_Meeting_July_14,_2016&action=edit&section=10>]
>
>   * Bobby presented current status of HV boards
>   * Boards were manufactured slightly wider than than nominal width
>     (9.6in). Since boards are laid out close-packed, this extra width
>     added up over width of plate.
>   * Sides were sanded to slightly less than nominal width allowing
>     them all to be properly positioned
>   * Bias boards are now expoxy'd to plate
>   * Capacitors that stand HV off from signal lines were soldered.
>       o Small prototype used surface mount while full sized prototype
>         used through-hole
>       o Design feature was missed by everyone that HV wire runs right
>         over through holes on other side of board. This could short
>         capacitor and physically displace wire if solder bumps were
>         left there.
>           + These have been ground down on full scale prototype, but
>             will be fixed for next iteration of board.
>   * Bobby will come to JLab on Mon. July 18 for 6 weeks. Tim has some
>     cubicle space in TED with a computer he can use.
>
>
>     FMWPC Construction[edit
>     <https://halldweb.jlab.org/wiki/index.php?title=%CE%A0_polarizability_Meeting_July_14,_2016&action=edit&section=11>]
>
>   * Rory gave an update on FMWPC construction
>   * G10 is now attached to Al plate using thin layer of epoxy
>       o Some care taken to calculate and measure correct amount of
>         epoxy to get 4-5 mil expoxy layer
>       o G10 plate boundaries seem well aligned. Difficult to detect
>         boundary via sense of touch
>   * O-ring machinging is complete
>   * Purchased 6 ft ACME rod for aligning wires when attaching to chamber
>       o acme rods have square thread grooves rather than "V" shaped
>         grooves
>       o these are used in things like 3D printers for accurate positioning
>       o Measured with high precision ruler to be within about 10 mil
>         over 6 ft.
>   * Ordered class 3 "V"-groove rod from McMaster-Carr and will measure
>     once it arrives.
>   * Presentation/discussion of TOF triggering was deferred until later
>     due to Andrew having to leave and us running low on time
>
>
>     π^+ π^-  simulation[edit
>     <https://halldweb.jlab.org/wiki/index.php?title=%CE%A0_polarizability_Meeting_July_14,_2016&action=edit&section=12>]
>
>   * Deferred presentation of Elton's results due to lack of time
>
>
>     CPPsim[edit
>     <https://halldweb.jlab.org/wiki/index.php?title=%CE%A0_polarizability_Meeting_July_14,_2016&action=edit&section=13>]
>
>   * David gave an abbreviated presentation of the status of simulating
>     μ/π separation
>   * Tools exist in a form that this type of study can now proceed.
>   * David will talk with Bobby next week about continuing this during
>     his visit to JLab.
>
>
>
>
> _______________________________________________
> Halld-cpp mailing list
> Halld-cpp at jlab.org
> https://mailman.jlab.org/mailman/listinfo/halld-cpp