S Temple CLRC1 End-cap Mechanics FDR Cooling Structures Steve Temple, RAL 1 November 2001

S Temple CLRC2 End-Cap Disc Services Cooling Structures l Full details - See ATL-IS-ER-0021 l Cooling Circuit Layout »3 circuits per quadrant - corresponding to inner, middle and outer module rings »3 separate Inlets, 3 outlets are manifolded at patch panel »Outer and middle module Circuits - Two point cooling »Inner module circuit - Single point cooling »Bend radii (inner) kept to 5 times OD i.e mm l Cooling Component Materials/Joining Techniques »C-C cooling blocks »CuNi pipe - 3.6mm ID, 70 µm Wall »Cu plating (sputter coat + electroplate) of cooling blocks enables soft soldering to cooling pipe

S Temple CLRC3 l Mechanical Requirements »Position modules to a positional tolerance of 134 microns (diameter) in the R-phi direction, for one module relative to its neighbour »Provide co-planar mounting surfaces for modules »Minimise forces transferred to the support structure i.e. carbon fibre disc »Operational for 10 years »Lowest possible mass l Thermal Requirements »To ensure the highest temperature of any part of the silicon on a module doesn’t exceed -7 °C End-Cap Disc Services Cooling Structures

S Temple CLRC4 l Cooling Pipe Circuit Design »CuNi material chosen for its excellent resistance to corrosion, and its excellent solderability »‘Wiggly’ pipe Layout reduces forces on disc from thermal contractions and pipe manufacturing tolerance –Thermal Contraction Forces Forces calculated using an FE model, using following material properties and boundary conditions : E=152 GPa,  = 12e-6/K,  T=50K –Pipe Manufacturing Tolerances Deviation of pipe bend centres from nominal positions kept to a minimum, through tooling design In addition stress relieving of manufactured circuits is proposed - testing is planned in next round of prototyping End-Cap Disc Services Cooling Structures

S Temple CLRC5 Inner Circuit End-Cap Disc Services Cooling Structures

S Temple CLRC6 Outer Circuit End-Cap Disc Services Cooling Structures

S Temple CLRC7 Middle Circuit End-Cap Disc Services Cooling Structures

S Temple CLRC8 l Cooling Pipe Prototyping »First prototype - Inner cooling circuit for system test »Old circuit design - Internal bend radii of 14mm »Ice used as filler material »Custom made pipe bender designed and manufactured »Manufactured at RAL End-Cap Disc Services Cooling Structures

S Temple CLRC9 l Cooling Pipe Prototyping (Cont’d) »Second prototype - Single U shaped bend »Internal bend radii of 20mm - 5 x OD »Cerobend used as filler material »Swaged ends - enables low mass joining of pipes »Manufactured by established pipe bending company End-Cap Disc Services Cooling Structures

S Temple CLRC10 l Cooling Block Design »Primary Cooling Block Thermal Design –C-C material chosen for good thermal conductivity W/m 2 K (fibre direction), 50 W/m 2 K (transverse direction) –Fibre orientation optimised –Straight split corresponding to hybrid and silicon –Further details see thermal performance Mechanical Design –Machined module location boss –Planar module mounting surface wrt block mounting surface –Accurate cooling block height End-Cap Disc Services Cooling Structures

S Temple CLRC11 l Cooling Block Design (Cont’d) »Second Point Cooling Blocks Thermal Design –C-C material chosen for good thermal conductivity W/m 2 K (fibre direction), 50 W/m 2 K (transverse direction) –Fibre orientation optimised Mechanical Design –As primary cooling block »Second Point Mounting Blocks Thermal Design –No thermal requirements - Made from low mass PEI polymer Mechanical Design –As primary cooling block End-Cap Cooling Structures Cooling Block Design

S Temple CLRC12 l Cooling Block Prototyping »Two prototyping exercises (old and current design) »Several manufactured, metrology checked to assess ability to machine key features within appropriate tolerances –3mm OD location boss –Parallelness between bottom and top surfaces –Block height dimension End-Cap Cooling Structures Cooling Block Design

S Temple CLRC13 End-Cap Disc Services Cooling Structures l Cooling Block Prototyping (Cont’d) »Current cooling block design metrology results »Improvements to design for machining operations simplification identified

S Temple CLRC14 l Joining of C-C Blocks to Cooling Pipe »Soldering of cooling blocks to pipe –Good thermal joint –Good mechanical joint - Soldered joint sample (using swaged end) undergone helium vacuum leak test –Standard SnPb (60/40) solder with non-corrosive Castolin 197 flux. –Requires Cu plating of C-C block »Cu Plating of C-C Blocks –Plating trials show good adhesion to C-C base material achieved by : Cleaning, Cu Sputtering, Cu Electroplating and Au Flash (to prevent copper oxidisation) –15 micron Cu plating followed by 2 micron Au flash End-Cap Disc Services Cooling Structures

S Temple CLRC15 l Cooling Structure Precision Assembly »To achieve positional tolerances required a precision assembly technique is performed during the disc services to disc assembly stage »This involves a precision rotary stage (r-phi) and an alignment arm (providing radial position) »Details see ATL-IS-ER-0022 End-Cap Disc Services Cooling Structures

S Temple CLRC16 l Cooling Structure Precision Assembly (Cont’d) »Blocks are required to be positioned in r-phi with a positional tolerance of 66 microns - Out of 134 micron error budget »Results show this is readily achievable using this method End-Cap Disc Services Cooling Structures

S Temple CLRC17 l Thermal Performance »Extensive prototype testing and thermal simulation carried out on the Baseline Design (see ATL-IS-ER-0009) –Full cooling quadrant (3 circuits) manufactured and tested on evaporative cooling rig –Dummy thermal module mounted on sector and tested –Successfully demonstrated a coolant temperature of -20 to -22 °C was sufficient to keep the inner module below - 7 °C. –Design consisted of Aluminium Alloy cooling blocks joined to Aluminium cooling pipes. –Effect of material changes therefore need to be assessed End-Cap Disc Services Cooling Structures

S Temple CLRC18 l Thermal Performance (Cont’d) »Assessment of cooling block material change –C-C block substituted into the simulation. Again boundary conditions W/m  C (7.5 W, 1W) –Minimal change on silicon side. Better performance on hybrid side. Al T sil =-11.5°C C-C T sil =-11.3°C Al T Hyb =-6.9°C C-C T Hyb =-8.4°C End-Cap Disc Services Cooling Structures

S Temple CLRC19 l Thermal Performance (Cont’d) »Assessment of cooling pipe material change –Reduction in thermal conductivity and wall thickness results in reduction of convective heat transfer area. –However as htc increases with heat flux, this effect will be decreased. –Small scale prototype testing on an evaporative C3F8 cooling rig is planned End-Cap Disc Services Cooling Structures