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Hall D Suggestions

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					 Detector for GlueX

Physics   Beamline    GlueX     Software    Computing
                                                         PRL
           Hall D    Detector    Trigger   Environment

          JLab PAC 23
          Jan 20, 2003
What is needed?

   9-GeV polarized photon beam
       Coherent bremsstrahlung beam
   Hermetic detector for multi-particle charged
    and neutral final statesCharged
       Solenoid-based detector
   Select events of interest with high sensitivity
       High DAQ rate capability with software trigger
   Analysis environment for successful PWA
Construction Site
Status of Civil Design

   Credible optics design
   Layout that provides room for detectors and
    access to equipment
   Beam containment proposal
   Concept for civil design
   GEANT Calculations show that the shielding
    satisfies radiation protection guidelines
Hall D site layout
       Coherent bremsstrahlung beam
         Delivers the necessary polarization, energy
         and flux concentrated in the region of interest




                                    Linear Polarization
Flux




                                                          P = 40%




         Photon beam energy (GeV)                                   Photon beam energy (GeV)
 Hybrid decays
GlueX will be sensitive to a wide variety of decay modes - the
measurements of which will be compared against theory predictions.

Gluonic excitations transfer angular momentum in their decays to
the internal angular momentum of quark pairs not to the relative angular
momentum of daughter meson pairs - this needs testing.

   For example, for hybrids:     X    b1        favored

   Measure many decay modes!     X             not-favored


   To certify PWA - consistency checks will be made among
   different final states for the same decay mode, for example:

                            0   3
                           
                                                               Should give
                 b1                                         same results
                            0      2   
                           
                          
GlueX detector
Solenoid ships from Los Alamos
Unloading at IUCF
Exploded view of the GlueX detector


                                                           CERENKOV   TOF   Pb-GLASS DET




                                                                                           12.00
           TARGET   VTX
                           CDC
                                                     FDC




The components are extracted by “4 ft” from each other for maintenance.
Particle kinematics
              p → X p → K+K─+─ p



                                       Most forward
       All particles                     particle
GlueX Detector
Central tracking
Straw tube chamber




                     Vertex Counter
Forward drift chambers
Charged particle resolution
Calorimetry
                                                  Pb Glass
                       Barrel
                                      Built by IU for BNL Exp 852




                                                0 




Pb/SciFi detector based on KLOE
s/E = 4.4 %/ √E, threshold = 20 MeV
st = 250 ps                                       Mass 
Particle identification
Time-of-flight, Cerenkov counter, and constraints for exclusive events
                                             p → K*K*p, E = 9 GeV
Hall D Prototype (IHEP Run 2001)
                                         Time Resolution (2cm by 6 cm Bar) vs. Position
                                                                           90


                                                                           80


                                                                           70
Time Resolution (ps)




                                                                           60


                                                                           50


                                                                           40


                                                                           30
                          Poor PM was on this end.
                                                                                    Predicted resolution for one bar, beam thru 2 cm.
                                                                           20
                                                                                    Predicted resolution for one bar, beam thru 6 cm.
                                                                                    Predicted resolution for two bars, beam thru 6 cm.
                                                                           10       Measured resl'n, 6 cm, two bars, no weighting.
                                         42 ps avg. resolution                      Measured resl'n, 6 cm, two bars with weighting.
                                                                            0
                       -100        -80         -60        -40    -20            0           20            40            60               80   100

                                                                       Position (cm)

                                                                                                                                 R. Heinz / IU
PID with Cerenkov and forward TOF
TOF s =100 ps resolution   p → K+K+p, E = 9 GeV




             n= 1.0014                      n= 1.0024
                              Mas s(X) = 2.0 GeV
                  0.2                                          5 GeV                     0.2




  Acceptance is high and uniform
                   0

                   p -> p  
                   -1   -0.8 -0.6 -0.4 -0.2   -0
                                         Cos( GJ)
                                                   0.2   0.4   0.6    0.8   1
                                                                                        
                                                                                             0
                                                                                                 -3            -2        -1        0
                                                                                                                                   GJ
                                                                                                                                           1    2   3



                                                                     p  Xn       n
                   1                                                                1
                   1                                                                         1


                  0.8                                                            0.8
                  0.8                                                                    0.8

                        Gottfried-Jackson frame:
                  0.6                                                            0.6

Acceptance in
                  0.6                                                                    0.6
                              the = 1.4 frame of X
                          In Mas s(X)rest GeV
                            Mas s(X) = 1.4 GeV
                                                                                                                    Mass [X] = 1.4 GeV
                  0.4     the decay angles are
                            Mas s(X) = 1.7 GeV                                   0.4
                                                                                                                    Mass [X] = 1.7 GeV
                  0.4        Mas s(X) = 1.7 GeV                                          0.4
Decay Angles              theta, phi GeV
                            Mas s(X) = 2.0 GeV
                             Mas s(X) = 2.0
                                                         5 GeV
                                                           8 GeV                                                    Mass [X] = 2.0 GeV
                  0.2                                                            0.2
                  0.2                                                                    0.2

                   0                                                                0
                   -1 -0.8 -0.6 -0.4 -0.2 -0 0.2 0.4 0.6 0.8
                   0                                         1                          -3 0          -2            -1      0          1    2   3
                    -1 -0.8 -0.6 -0.4 Cos( )0.2 0.4 0.6 0.8
                                       -0.2 -0                              1                    -3            -2         
                                                                                                                         -1        0       1    2   3
                                            GJ
                                         Cos( GJ)                                                0        0
                                                                                                                              GJ
                                                                                                                                   GJ
 assuming 9 GeV                                                         p  Xn    n
 photon beam
                   1                                                                1
                   1                                                                         1

                  0.8                                                            0.8
                  0.8                                                                    0.8

                  0.6                                                            0.6
                  0.6        Mas s(X) = 1.4 GeV                                          0.6
                              Mas s(X) = 1.4 GeV
                  0.4        Mas s(X) = 1.7 GeV                                  0.4
                  0.4         Mas s(X) = 1.7 GeV                                         0.4
                             Mas s(X) = 2.0 GeV
                  0.2
                              Mas s(X) = 2.0 GeV
                                                         8 GeV                   0.2
                  0.2                                      12 GeV                        0.2

                   0                                                                0
                   -1 -0.8 -0.6 -0.4 -0.2 -0 0.2 0.4 0.6 0.8
                   0                                          1                         -3 0          -2            -1      0          1    2   3
                    -1 -0.8 -0.6 -0.4 Cos( GJ)0.2 0.4 0.6 0.8
                                       -0.2 -0                              1                    -3            -2         
                                                                                                                         -1 GJ     0       1    2   3
                                         Cos( GJ)                                                                                 GJ
 Trigger and DAQ
                                                Physics
Start @ 107 /s                                 Signal
Open and unbiased trigger   Level 1
Design for 108 /s
    15 KHz events to tape


Level 1 trigger system
With pipeline electronics
                                      Level 3
Software-based
Level 3 System
  Trigger and DAQ
                              Hadronic rate in detector

                                                     Physics
                                                     Signal
                            Level 1

Start @ 107 /s
Open and unbiased trigger
Design for 108 /s
    15 KHz events to tape


Level 1 trigger system                     Level 3
With pipeline electronics


Software-based
Level 3 System
Trigger Rates




Output of Level 3
software trigger
  Luminosity limits




GlueX raw rates will be
well below currently
running CLAS electron
beam experiments
DAQ architecture
                 90 VME
              front-end crates



                                       Gigabit switch
                                          200 KHz

             8 event builders


          200 Level 3 Filter Nodes   8 100-Mbit switches




            4 event recorders
                                     Network connection
               4 tape silos             to silo 15 KHz
Fully pipeline system of electronics
Deadtimeless
Expandable                                  Flash ADCs: 13000 channels
No delay cables                             TDCs      : 8000 channels




(Non-pipeline: Limits photon flux < 107/s, incurs deadtime, requires delay cables)
  Data Volume per experiment per year
  (Raw data - in units of 109 bytes)
                                                        E691
1000000
                                                        E665
                                                        E769

 100000                                                 E791

                                                        CDF/D0
                                                        KTeV
  10000                                                 E871
                                                        BABAR
                                                        CMS/ATLAS
   1000
                                                        E831
                                                        ALEPH
                                                        JLAB
    100
                                                        STAR/PHENIX

     1980              1990           2000   2010       NA48
                                                        ZEUS




          But: collaboration sizes!          Ian Bird
Data Handling and Reduction
                               CLAS                 GlueX
Event size                      5 KB                 5 KB
Data volume                 100 TB/year          1000 TB/year
cpu speed                     0.4 GHz              6.4 GHz
cpu time per event            100 ms                15 ms
cpu count                        150                 225
Reduction speed                7 MB/s              75 MB/s
Throughput limit             cpu speed            cpu speed
Reduction time                0.5 year             0.4 year
          Data rate up by 10, computer costs down by > 5

       GlueX Computing Effort ~ 2 x CLAS
  Computing Model                                        Tier “2” Centers


                                                                     Calibration
                Tier “1” Center (Jlab)                  20 MB/s

Physics Data
                1 PB/year                 0.2 PB/yr                   Physics
                                                                      Analysis
     DAQ                   Event
 Level 3 Farm           Reconstruction      70 MB/s
                                                                      Physics
                 100 MB/s                                             Analysis


                                                           20 MB/s
   Tier “2” Simulation      Monte Carlo        0.2 PB
       Center
      Detector designed for PWA
 Double blind studies of 3 final states
          r        
 
         X              
 p                 
             n               Linear Polarization
              a2         2
                                             =1

                                         =1
GJ




                                             =1

                                         =1

                                              =1

             m3 [GeV/c2]
 Leakage
An imperfect understanding of the
detector can lead to “leakage” of
strength from a strong partial wave
into a weak one.

STRONG: a1(1260) (JPC=1++)

Break the GlueX Detector (in MC).

Look for Signal strength in Exotic 1-+



Under extreme distortions, ~1% leakage!
Ongoing R&D effort

   Solenoid – shipped to IUCF for refurbishment
   Tracking – testing straw chamber; fabricating endplate prototype
    (CMU)
   Vertex - study of fiber characteristics (ODU/FIU)
   Barrel calorimeter – beam tests at TRIUMPF; fabricated first test
    element of the Pb/SciFi matrix (Regina)
   Cerenkov counter – magnetic shield studies (RPI)
   Time-of-flight wall – results of beam tests at IHEP show s<5 ps (IU)
   Computing – developing architecture design for Hall D computing
   Electronics – prototypes of pipeline TDC and FLASH ADC (Jlab/IU)
   Trigger – Studies of algorithm optimization for Level 1(CNU)
   Photon tagger – benchmarks of crystal radiators using X-rays
    (Glasgow/UConn)
   Civil – beam height optimized; electron beam optics shortens length of
    construction; new radiation calculations completed (Jlab)
                                                                                     7

 Benchmarks of Diamond Crystals

                       High Quality                              Poor Quality




      Stone 1482A Slice 2                                   Stone 1407 Slice 1
(10mmx10mm X-ray rocking curve)                         (4mm x 4 mm X-ray rocking curve)

R.T. Jones, Newport News, Mar 21, 2002
                                         Richard Jones / Uconn
Straw Tube chamber work
Graduate Students: Zeb Krahn
and Mike Smith
 Built a b-gun using a 10 mCi
 106Ru Source


                       Getting coincidences with
                       both cosmics and b’s
                       cosmics




ArCO2 90-10
ArEthane 50-50
                       b gun       Carnegie Mellon University
Building a Prototype Endplate

  Build endplates as 8 sections
  with tounge and groove.

 Checking achievable accuracy
Barrel calorimeter prototyping

                      Hybrid pmts can operate
 Pb/SciFi prototype   in fields up to 2 Tesla




                                University of Regina
FLASH ADC
Prototype




            250 MHz, 8-bit FADC




                 Paul Smith / IU
Pipeline TDC


                                                      s = 59 ps




                                              TDC counts


      First prototype results: high resolution mode

                             Jlab DAQ and Fast Electronics Groups
Cassel review of Hall D concluded
“The experimental program proposed in the Hall D Project
is well-suited for definitive searches for exotic states that
are required according to our current understanding of
QCD”

“An R&D program is required to ensure that
  the magnet is usable,                          Working with input
                                                  from many groups on
  to optimize many of the detector choices,      electronics, DAQ,
                                                  computing, civil,
  to ensure that the novel designs are feasible,
                                                  RadCon, engineering,
                                                  and detector systems.
    and to validate cost estimates.”

				
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