Detector for Glue X Physics Beamline Hall D
Detector for Glue. X Physics Beamline Hall D Glue. X Detector JLab PAC 23 Jan 20, 2003 Software Trigger Computing Environment PRL
What is needed? n 9 -Ge. V polarized photon beam q n Hermetic detector for multi-particle charged and neutral final states. Charged q n Solenoid-based detector Select events of interest with high sensitivity q n Coherent bremsstrahlung beam High DAQ rate capability with software trigger Analysis environment for successful PWA
Construction Site
Status of Civil Design n n Ø n n 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 Flux Linear Polarization Delivers the necessary polarization, energy and flux concentrated in the region of interest Photon beam energy (Ge. V) P = 40% Photon beam energy (Ge. V)
Hybrid decays Glue. X 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: favored Measure many decay modes! not-favored To certify PWA - consistency checks will be made among different final states for the same decay mode, for example: Should give same results
Glue. X detector
Solenoid ships from Los Alamos
Unloading at IUCF
Exploded view of the Glue. X detector TOF Pb-GLASS DET 12. 00 CERENKOV TARGET VTX CDC FDC The components are extracted by “ 4 ft” from each other for maintenance.
Particle kinematics g p → X p → K +K ─ p + p ─ p All particles Most forward particle
Glue. X Detector
Central tracking Straw tube chamber Vertex Counter
Forward drift chambers
Charged particle resolution
Calorimetry Barrel Pb Glass Built by IU for BNL Exp 852 p 0 h Pb/Sci. Fi detector based on KLOE s/E = 4. 4 %/ √E, threshold = 20 Me. V st = 250 ps Mass gg
Particle identification Time-of-flight, Cerenkov counter, and constraints for exclusive events gp → K*K*p, Eg = 9 Ge. V
Hall D Prototype (IHEP Run 2001) R. Heinz / IU
PID with Cerenkov and forward TOF s =100 ps resolution n= 1. 0014 gp → K+K p+p p, Eg = 9 Ge. V n= 1. 0024
Acceptance is high and uniform Acceptance in Decay Angles assuming 9 Ge. V photon beam Gottfried-Jackson frame: In the rest frame of X the decay angles are theta, phi Mass [X] = 1. 4 Ge. V Mass [X] = 1. 7 Ge. V Mass [X] = 2. 0 Ge. V
Trigger and DAQ Start @ 107 g/s Open and unbiased trigger Design for 108 g/s 15 KHz events to tape Physics Signal 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 g/s Open and unbiased trigger Design for 108 g/s 15 KHz events to tape Level 1 trigger system With pipeline electronics Software-based Level 3 System Level 3
Trigger Rates Output of Level 3 software trigger
Luminosity limits Glue. X 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 4 event recorders 4 tape silos 8 100 -Mbit switches Network connection to silo 15 KHz
Fully pipeline system of electronics üDeadtimeless üExpandable üNo delay cables Flash ADCs: 13000 channels 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) But: collaboration sizes! Ian Bird
Data Handling and Reduction Event size Data volume cpu speed cpu time per event cpu count Reduction speed Throughput limit Reduction time CLAS 5 KB 100 TB/year 0. 4 GHz 100 ms 150 7 MB/s cpu speed 0. 5 year Glue. X 5 KB 1000 TB/year 6. 4 GHz 15 ms 225 75 MB/s cpu speed 0. 4 year Data rate up by 10, computer costs down by > 5 Glue. X Computing Effort ~ 2 x CLAS
Computing Model Tier “ 2” Centers Tier “ 1” Center (Jlab) 20 MB/s Calibration Physics Data 1 PB/year DAQ Level 3 Farm 0. 2 PB/yr Event Reconstruction Physics Analysis 70 MB/s Physics Analysis 100 MB/s 20 MB/s Tier “ 2” Simulation Center Monte Carlo 0. 2 PB
Detector designed for PWA Double blind studies of 3 p final states g p r p X p p n a 2 Linear Polarization p 2 h=+1 f. GJ h=-1 h=+1 m 3 p [Ge. V/c 2]
Leakage An imperfect understanding of the detector can lead to “leakage” of strength from a strong partial wave into a weak one. STRONG: a 1(1260) (JPC=1++) Break the Glue. X Detector (in MC). Look for Signal strength in Exotic 1 -+ Under extreme distortions, ~1% leakage!
Ongoing R&D effort n n n 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/Sci. Fi matrix (Regina) Cerenkov counter – magnetic shield studies (RPI) Time-of-flight wall – results of beam tests at IHEP show s<50 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 Ø Benchmarks of Diamond Crystals High Quality Poor Quality Stone 1482 A Slice 2 (10 mmx 10 mm X-ray rocking curve) R. T. Jones, Newport News, Mar 21, 2002 Stone 1407 Slice 1 (4 mm x 4 mm X-ray rocking curve) Richard Jones / Uconn
Straw Tube chamber work Graduate Students: Zeb Krahn and Mike Smith Built a b-gun using a 10 m. Ci 106 Ru Source Getting coincidences with both cosmics and b’s cosmics Ar. CO 2 90 -10 Ar. Ethane 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 Pb/Sci. Fi prototype Hybrid pmts can operate 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 ü the magnet is usable, Working with input from many groups on ü to optimize many of the detector choices, electronics, DAQ, computing, civil, ü to ensure that the novel designs are feasible, Rad. Con, engineering, and detector systems. and to validate cost estimates. ”
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