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Thomas Jefferson National Accelerator Facility Page 1
CD Workshop Dec 2-3, 2009
CLAS12 Central DetectorOverview and Integration
David Kashy Hall B Lead Engineer
CLAS CD Workshop Saclay
December 2-3, 2009
Thomas Jefferson National Accelerator Facility Page 2
CD Workshop Dec 2-3, 2009
Outline
• System Overview• Solenoid and Support• HTCC and Moeller Shields• CTOF and Support• SVT and support• Summary/Conclusion
Thomas Jefferson National Accelerator Facility Page 3
CD Workshop Dec 2-3, 2009
Hall B Overview
Hall B Space Frame
Hall B – 98’ Diameter
20 Ton Polar Crane
Beam entry tunnel
Beam dump tunnel
Cryogenic Supply and Return Line
Thomas Jefferson National Accelerator Facility Page 4
CD Workshop Dec 2-3, 2009
CLAS12 Detectors
Silicon Vertex Tracker
Central Time of Flight
Solenoid
High Threshold Cerenkov
3 Regions of Drift Chambers
Torus
3 Panels of Time of Flight –1a & 2 reused
from CLAS
Low Threshold Cerenkov – Reused
from CLAS
Electromagnetic Calorimeter –
Reused from CLAS
Pre-Shower Calorimeter
Thomas Jefferson National Accelerator Facility Page 5
CD Workshop Dec 2-3, 2009
Solenoid
• Purposes are:– Central field for tracking– Provide magnetic shielding of Moeller
Electrons• Peak field 5T• Homogeneous central region 1e-4 in
Ø =25mm L = 40mm • Limited fringe field at locations of
High Threshold Cerenkov PMT’s • Contract awarded to Wang NMR
11/20/2009• Solenoid supported by 3 legged cart.
Solenoid Lead can and Cryo reservoir
Magnet Cryostat
Thomas Jefferson National Accelerator Facility Page 6
CD Workshop Dec 2-3, 2009
Central Detectors
• Central tracker and Time-of-Flight detectors are attached directly to the solenoid. This provides stable reliable support that will limit external vibrations since its mass is very large ~20tonn
Thomas Jefferson National Accelerator Facility Page 7
CD Workshop Dec 2-3, 2009
Plans for Mounting to Solenoid
SVT MountsCTOF Mounts
Solenoid attachment to
cart
• Solenoid specification shows desired mounting to be at ends of magnet. • Details will need to be worked out with Vendor• CTOF will be mounted from both ends• Central Tracking Detectors must be mounted from upstream end only or we
will loose HTCC and CLAS12 acceptance
Thomas Jefferson National Accelerator Facility Page 8
CD Workshop Dec 2-3, 2009
High Threshold Cerenkov Counter
• HTCC surrounds the solenoid and CD from outside
• It also protrudes inside with close clearance to the CTOF and also FST or other central tracker
• Several Moeller Electron Shields are planned
• They are envisioned to be cantilevered off the Torus
• Materials to be Lead or Tungsten or a combination
• Different configurations depending on the type of run (rastered or normal beam)
High Threshold Cerenkov Outer cone- very close to
light guides
Thomas Jefferson National Accelerator Facility Page 9
CD Workshop Dec 2-3, 2009
Central Detector Section View
• CTOF – ID = 500mm– OD = 563 mm
• HTCC starts at 380mm (desired to start earlier)
• Moeller Shield fits very closely to inside cone of HTCC
High Threshold Cerenkov Outer cone- very close to
light guides
Moeller Shield
Thomas Jefferson National Accelerator Facility Page 10
CD Workshop Dec 2-3, 2009
Solenoid and Central Tracker
• SVT/Central Tracker supported off the Solenoid upstream Flange
• 6 link support system is the current design
Thomas Jefferson National Accelerator Facility Page 11
CD Workshop Dec 2-3, 2009
Latest Central Tracker Layout
• Two size BST stave assemblies
• Target size limited to 3” OD
• Considering removable R1 BST to allow HD Ice target
• Max radius of Central Tracker 238mm
• Note the HTCC starts at 380 mm so there is some room for Micro Megas
Thomas Jefferson National Accelerator Facility Page 12
CD Workshop Dec 2-3, 2009
Silicon Vertex Tracker
Cold plate with brass inserts
Stave support
Stave
• Cooling analysis shows efficient heat removal• Deflection analysis complete • Assembly and alignment methods will be
confirmed with region 1 barrel assembly• Documentation and tech notes at
http://clasweb.jlab.org/wiki/index.php/CLAS12_SVT
Thomas Jefferson National Accelerator Facility Page 13
CD Workshop Dec 2-3, 2009
Latest Stave Design
Copper/Aluminum Nitride
FR4
Silicon 3 places
FR4
Copper
Rohacell
• Many designs considered• Latest design uses Silicon Wafer as
structure as well as detector, (proposed by M. Merkin and analyzed by S. Mandal)
• Prototype cores formed at JLab in mold• First results give core thickness
2.78mm +/- 0.015mm, with higher quality mold we expect better
Thomas Jefferson National Accelerator Facility Page 14
CD Workshop Dec 2-3, 2009
SVT Engineering Results Item Units ValueCoolant temperature
C 15
Peak temperature C 22.1Maximum deflection
Microns 10 fixed-pinned (R3&4)
R2 BST thermal analysis
Max. Deflection ~10.5m
R3&R4 BST deflection analysis
Max. Temp ~22.1 C
Thomas Jefferson National Accelerator Facility Page 15
CD Workshop Dec 2-3, 2009
CTOF
• There have been two parallel design efforts• One with standard PMT’s and one with high magnetic
field PMT’s decision on which one is pending more study on HF PMT design
Thomas Jefferson National Accelerator Facility Page 16
CD Workshop Dec 2-3, 2009
Solenoid and CTOF
• CTOF is supported from both the upstream and downstream flanges of the solenoid
• Room for Central calorimeter or Neutron detector is being left for future upgrade
Thomas Jefferson National Accelerator Facility Page 17
CD Workshop Dec 2-3, 2009
Installation of Counter Assembly
• Reference (conservative) design shown here
• Counters will be built and tested complete
– Light guides glued to scintillator– Wrapped and light sealed– PMT’s and 2 of the 3 layers of shield
pre-installed• Individual counter assemblies will be
installed one at a time• A strong-back will support the
counters to prevent bending and glue joint failure
• Installation fixture will clock the light guide assembly to the proper Φ angle
Counter exploded view
Strong Back
Thomas Jefferson National Accelerator Facility Page 18
CD Workshop Dec 2-3, 2009
Counter Assembly Installed
• Installation fixture will roll counter assembly into position through the Solenoid bore
• Light guide assembly will be mounted to permanent clamps, then strong-back clamps can be removed
Thomas Jefferson National Accelerator Facility Page 19
CD Workshop Dec 2-3, 2009
Beam Line• Most Beam Line Devices reused from CLAS
– Steering , focusing and raster magnets– Beam Profile Monitors and Beam Position Monitors– Cryogenic Target– Photon Devices will be left on beam line including Photon Tagger,
radiators, collimators and pair spectrometer
• Shielding after target simulated and defined through the Torus• Re-arrangement of Moeller measurement system components, a
study optimizing this is underway Shielding
Cryogenic Target and
Cart
BPM’s (2)
Raster Magnets (2 pairs)
Tagger Magnet and other
Photon Devices
Thomas Jefferson National Accelerator Facility Page 20
CD Workshop Dec 2-3, 2009
Hall B Prepared for CLAS12 Installation
Forward Carriage with
Electromagnetic Calorimeters
Space Frame Cleared of Beam Line equipment
Thomas Jefferson National Accelerator Facility Page 21
CD Workshop Dec 2-3, 2009
CLAS12 installation schedule
Thomas Jefferson National Accelerator Facility Page 22
CD Workshop Dec 2-3, 2009
CD installation
• An additional level will be added to the space frame for the CD and HTCC
• Torus will be installed next
• The Solenoid will be craned in
• CTOF will be installed after solenoid acceptance testing
• Central Tracker is installed last
Thomas Jefferson National Accelerator Facility Page 23
CD Workshop Dec 2-3, 2009
Torus Assembled and Central Detector added
Solenoid and Central Detector - slides on rails into the space
frame for maintenance
Torus positioned and
alignedSpace frame
addition for Central Detector and HTCC
Thomas Jefferson National Accelerator Facility Page 24
CD Workshop Dec 2-3, 2009
Safety• To work in Hall B all persons must be Trained and Qualified
• All work in Hall B work is scheduled and reviewed by the Hall Work Coordinator
• Independent activities have been and will continue to be reviewed for space and resource interferences
• Stop Work Program will always apply
• ISM principles must be followed
• Lock Tag and Try/LOTO will be used
• Tested and Inspected lifting fixtures
• PPE will be worn as required
• Hall B is a low radiation environment this will allow most items to be removed from the hall after survey w/o delay.
Thomas Jefferson National Accelerator Facility Page 25
CD Workshop Dec 2-3, 2009
Summary
• Design of CTOF and SVT proceeding
• Will be working with Solenoid vendor on supports for CD
• Looking forward to contributions on Central Detector
• Planning for installation being integrated in the design phase
Thomas Jefferson National Accelerator Facility Page 26
CD Workshop Dec 2-3, 2009
CLAS12 is COMPLETE!