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This document provides an overview of estimating the material budget for the SCT Barrel by Alessandro Tricoli from RAL. It covers procedures, documentation, modeling for simulation, on-barrel and off-barrel services, and comparison methods. Detailed information and raw data are accessible on the SCT Material Budget web page.
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BarrelSCT Material Budget By Alessandro Tricoli RAL ATLAS Physics meeting, 18th March 2008
R=3405 mm PPB1 PPF1 R=1150 mm PPB0 PPF0 PP1b PP0 PP1a Z = 0 ID gas barrier EC SCT Barrel SCT Overview • Procedure to estimate the SCT material budget • Documentation • Barrel • On-Barrel Services • comparison with weight measurements • Off-Barrel Services (radial & along inner cryostat wall) • End-Caps by Stephen Haywood Alessandro Tricoli, RAL
Collection of Material info • Bottom-up estimate: collect weights and compositions for each item including screws, washers, nuts etc. • Input information is collected from engineers who designed and built the detector: • using drawings and measured weights or CAD masses when no measurement is available. • When possible we compare our bottom-up estimate to measured weights of sub-detectors: • top-down estimate: weigh the whole sub-detector with extra temporary bits (i.e. support structures, trolley etc.) then subtract weight of extra bits. Barrel Thermal Enclosure HSP B6 Bearing Alessandro Tricoli, RAL
Modelling for Simulation • When raw data is collected materials are grouped into volumes to implement in GeoModel. • constraints: • balance between having fine granularity and minimising number of volumes to avoid slowing down simulation • have a realistic detector in the simulation avoiding clashes between sub-detector volumes (keeping also clearances for misalignments) • Material Volumes suggested by A. T. are passed to Pat W. and Vadim K. for coding into GeoModel • All materials shown today are included in G4 detector geometry CSC-03-00-00 Alessandro Tricoli, RAL
Documentation • Raw material data and simulation models are available on the SCT Material Budget web page http://hepwww.rl.ac.uk/atlas-sct/engineering/material_budget/ • Barrel Section with: • derived models: on-barrel and off-barrel services • link to taka Kondo web page for Modules (not discussed here) • X0 plots from Model: • using simplified geometries • X0 plots from Pat Ward using Geantino (geometry as in G4) • Comparison bottom-up mass estimate with top down measurement for barrel SCT • links to raw information from engineers • ATLAS note being written: common for barrel & end-cap services Alessandro Tricoli, RAL
On-Barrel ServicesBottom-up estimate • Modules done by Taka Kondo (not discussed here) • Tracking Volume Services for B3, B4, B5,B6: • Carbon Fibre Cylinders including flanges and end-clamps • Cooling Loops: pipes, inlet connectors, exhaust manifolds, U-bends, cooling blocks • Module support Brackets • Harnesses and Doglegs Example: excel sheet for CFRP Cylinder and Flange Alessandro Tricoli, RAL
B3 Cooling Inlet Cooling pipe Module Cooling Block Dogleg Optical Fibres LMTs Dogleg Bracket Cylinder Cooling Outlet (manifold) On-Barrel Services (pictures) Harness (LMTs, Dogleg, Fibers) Alessandro Tricoli, RAL
On-Barrel Services (masses) All barrel layers are treated similarily: main differences in multiplicity of objects (no. modules, brackets, cooling loops, cylinder radii etc.) Taka Kondo Module Mass: • 24.74 g Average module’s mass • 52.26 Kg Total mass for the whole barrel SCT. modules are the largest single contribution X0 Plots vs h From Model: Simplified det. geometry (disks & barrels) h h Alessandro Tricoli, RAL
On-Barrel Services (X0 plots in G4) Smeared vertex Component-by-component Smeared vertex Stacked components By Pat Ward using geantino events Alessandro Tricoli, RAL
Off-Barrel Services (spread sheet) • Services outside the Tracking Volume • Interlinks • Cooling Capillaries and Spiders • Thermal Enclosure (TE): ITE,OTE, Bulkhead, End-Panels • Heat Spreader Plate (HSP) • Heat Exchangers (HEX) including Heaters (“as built”, i.e. with dummy heaters) • PPB1 • Power Cables including Cable Trays Example: Excel sheet for Inner TE (ITE) Alessandro Tricoli, RAL
Thermal Enclosure (TE) End Panels Side Panels OTE Cooling Spiders ITE HEX (green) Heater Spreader Plate (HSP) Off-Barrel Services (pictures) B6 Bearing (with Interlinks are part of the barrel holding structure) Alessandro Tricoli, RAL
Off-Barrel Services (masses & X0) Includes all materials that run through HSP (HEX excluded): Off-barrel opto-harness, cooling and N2 pipes, DCS wires cables and cable trays are the largest single contribution X0 Plots vs h From Model: Simplified det. geometry (disks & barrels) Alessandro Tricoli, RAL
Off-Barrel Services (X0 plots in G4) Smeared vertex Component-by-component Smeared vertex Stacked components By Pat Ward using geantino Alessandro Tricoli, RAL
Mass and Radiation Length • Mass of on-barrel services 20% higher than previous estimates • Mass of off-barrel services 50% higher than previous estimates • X0 calculated analytically assuming simplified geometries • In agreement with Pat’s plot, using geantino events G4 • For |h|<0.5 on-barrel services and modules dominate • modules are the largest single contribution • For 0.5< |h|< 1.9 off-barrel services dominate • cables and cable trays are the largest single contribution Simplified Model Simplified Model Alessandro Tricoli, RAL
ComparisonBottom-up vs Top-down estimates… • Top-down: measurements after installation • SCT Barrel not weighed, can only be inferred: • TRT weighed and ID barrel • ID Barrel (weighed) = SCT + TRT + Extra Temporary Bits (Trolley+…) • SCT weight inferred from: ID Barrel – TRT – Extra Temp. Bits • Bottom-up: sum up masses of Modules, On-Barrel Services and some Off-Barrel services to be consistent with the measured object Alessandro Tricoli, RAL
Poor Accuracy due to TRT weight measurements (~20 Kg): • 727 Kg[=714 (measured) – 0.5 (St. St Manifold) + 8 (active gas manifold) +5.6 (cooling manifold) ] • 709 Kg[=699.5 (measured) + 6 (active gas manifold) +4.2 (cooling manifold) ] • Bottom-up estimate 691 Kg[=702.9 – 11.9 (cooling fluid)]by M. Goulette et al. M. Goulette (ATL-COM-INDET-2006-006) SCT= 175 (727Kg TRT) , 184 (av. 718Kg TRT) , 193 (709Kg TRT)Kg Top-down estimate SCT = (SCT+TRT+Extra Bits) – TRT – Extra Bits (Trolley, ISSS etc.) Alessandro Tricoli, RAL
Bottom-Up: SCT = 186Kg Bottom-Up - Top-DownDifference: +11(727Kg TRT), +2 (av. 718Kg TRT),-7(709Kg TRT)Kg Comparison with Bottom-up estimate • Trying to be consistent with measurement (very difficult!!): • SCT= Modules + B(3,4,5,6) services – Cooling Fluid + Capillaries&Spiders + Interlinks + TE SCT-Pixel Attachment & on-barrel FSI missing (light anyway) Alessandro Tricoli, RAL
Conclusions and Plans • Mass computation of SCT Barrel and close to completion in the volume within the cryostat wall • FSI to be added soon (only known bit missing) • Substantial increase in mass and X0 w.r.t. previous estimates/simulation (+20% on barrel services, +50% off-barrel services), especially at higher |h| due to more accurate computation of service contribution • Models implemented in GeoModel by Pat Ward. (available in Athena rel. 13) • Comparison between mass estimate and measurements: • Limited accuracy due to large uncertainty on TRT weight measurement: ~20Kg • Good Agreement within experimental accuracy • Documentation • Complete web page with raw info, pictures, model destricptions, plots • ATLAS Note write-up on going Alessandro Tricoli, RAL
EXTRAS Alessandro Tricoli, RAL
On-Barrel Services (X0 plots in G4) Un-smeared vertex (0,0,0) Stacked components Un-smeared vertex (0,0,0) Component-by-component By Pat Ward using geantino events Alessandro Tricoli, RAL
Off-Barrel Services (X0 plots in G4) Un-smeared vertex (0,0,0) Component-by-component Un-smeared vertex (0,0,0) Stacked components By Pat Ward using geantino Alessandro Tricoli, RAL
Inner Detector Volumes – from Grant, July 2006 Alessandro Tricoli, RAL