Thomas Jefferson National Accelerator Facility Page 1 IPR October Independent Project Review of 12 GeV Upgrade Jefferson Lab October 18-20, 2011 SVT Mechanical Design at JLAB Saptarshi Mandal

Thomas Jefferson National Accelerator Facility Page 2 IPR October Outline Overview of mechanical aspects of Barrel Silicon Tracker (BST) Discussion of mechanical and thermal design Assembly of the detector Quality Assurance of the detector Summary

Thomas Jefferson National Accelerator Facility Page 3 IPR October Central Tracker CTOF Solenoid SVT SVT Support and Alignment System

Thomas Jefferson National Accelerator Facility Page 4 IPR October Features of BST Four region barrel Region 1: 10 modules; Region 2: 14 modules; Region 3: 18 modules; Region 4: 24 modules Acceptance 35 o – 125 o Operating Temperature 20 o – 25 o C Low mass inside acceptance region

Thomas Jefferson National Accelerator Facility Page 5 IPR October Position Accuracy Module position accuracy (knowledge of position) ±54 µm, ±1350 µm, ±270 µm in X,Y,Z X Z Z X

Thomas Jefferson National Accelerator Facility Page 6 IPR October Barrel Silicon Tracker Downstream Support Ring HFCB Support Tube Tedlar Window Carbon Shell Cold Plate Modules

Thomas Jefferson National Accelerator Facility Page 7 IPR October Cold Plate Provides mechanical support to the BST Provides cooling for the electronics on the modules Copper Insert Coolant Channel

Thomas Jefferson National Accelerator Facility Page 8 IPR October Cold Plate and Support Rings Downstream Support Ring Upstream Support Ring Module Module is supported between upstream and downstream support rings Module is positioned by accurately machined pin holes in the two rings and the stave (Region 3 shown) Cold Plate

Thomas Jefferson National Accelerator Facility Page 9 IPR October BST Section View Coolant Channel Stave Support & Conductor Module Upstream Support Ring Insert

Thomas Jefferson National Accelerator Facility Page 10 IPR October Cold Plate Prototype Copper Inserts with fins Cooling Channel Cold Plate is in two parts -- One part with cooling channel machined in it Second part with slots machined to accommodate inserts Adhesive used – 3M DP 190

Thomas Jefferson National Accelerator Facility Page 11 IPR October Prototype contd. Upstream Support Ring Stave Support & Thermal Conductor

Thomas Jefferson National Accelerator Facility Page 12 IPR October Detector Assembly During Assembly- R3 Assembled R3 Locating Pin Assembly to be done in clean room environment Assembly sequence – R1  R2  R3  R4 Modules are positioned by accurate locating pins Modules are fastened down for good thermal contact at upstream end Design allows for removing an entire region as a unit

Thomas Jefferson National Accelerator Facility Page 13 IPR October Module Functions Mechanical support and positioning of sensors and electronics Cooling of ASICs Features Carbon skin (.250 mm) with Rohacell 71 core (2.5 mm) Rohacell 71 core replaced by copper core (2.5 mm) under electronics Kapton bus cable used for grounding on top and bottom surface Fastening Hole Hole for Locating Pin Slot for Locating Pin Sensors Bus Cable

Thomas Jefferson National Accelerator Facility Page 14 IPR October Module Close-up View Rohacell 71 Pitch Adapter Copper Heat Sink ASIC Carbon Fiber Silicon Sensor

Thomas Jefferson National Accelerator Facility Page 15 IPR October Stave with Electronics HFCB

Thomas Jefferson National Accelerator Facility Page 16 IPR October Stave Deformation Deflection based on gravity Boundary Condition: Fixed- Pinned Weight of electronics ~20 gm Max. Deflection : ~21  m

Thomas Jefferson National Accelerator Facility Page 17 IPR October Barrel Deformation Deflection based on gravity Max. Deflection : ~22  m (in horizontal modules)

Thomas Jefferson National Accelerator Facility Page 18 IPR October Stave Temperature Distribution Heat Input : 3W (Expected input ~2W) Coolant: Water Coolant temperature: 15 o C Nitrogen Purge at 20 o C Heat Sink Material : Copper Peak Temperature : 23 o C

Thomas Jefferson National Accelerator Facility Page 19 IPR October Highlights of Quality Assurance Plan Visual inspection of each module Dimensional accuracy check of modules using CMM to ensure compliance with engineering drawings Dimensional accuracy check of cold plate and all thermal and structural components to ensure that they meet drawing specifications First article tests of mechanical and thermal components to check engineering design Position of each module measured and recorded during assembly to provide accurate knowledge of position of each module

Thomas Jefferson National Accelerator Facility Page 20 IPR October Summary FEA showed deflections and temperature to be within acceptable range Prototype of the cold plate demonstrated the feasibility of the cooling method to be used Quality Assurance plan is well developed