1. 1 ATLAS Upgrade WP4 Face to Face meeting at Edinburgh - 11 th Jan 2011 WP4 task 2: Cooling activities Richard French – The University of Sheffield

2. Task 4 work area summary 2 Material metallurgy and pressure handling characteristics. Links to tube manufacturers for supply of bespoke tube Storage and stock taking of tube held to supply our R&D Transportation and shipping of components Bending of the desired tube into the cooling circuit design: Minimum bend radii tests for different diameters Cutting of and tube end preparation Joining of the tube: Advanced welding with TIG Orbital (tube-tube /temp connectors) NDT/DT (+ nasty chemistry) more metallurgy Studies of damage to electronics from welding Testing of the cooling circuit: Pressure test, Long term thermal cycling, Thermal shock Documentation Component identification, Test data and collation, CO2 cooling plant production - See John Hill’s talk. The cooling sub task4 is best summed up by looking at the main work areas (shown in the order the components are made)

3. Past 12 month summary 3 Weekly meetings held at 10am UK time just before the regular WP7/4 slot. Notes and presentations from any of our previous meetings can be found using the link below: https://twiki.cern.ch/twiki/bin/view/Sandbox/ATLASUpgradeUKweeklycoolingmeetings The next pages detail the past 12m as laid out in the “task 4 work area summery” on slide 2.

4. Material metallurgy & pressure handling characteristics. 4 316L Stainless Steel CP2 Titanium 3.175 OD x 0.20mm wall 3.175 OD x 0.18mm wall 2.000 OD x 0.14mm wall 2.175 OD x 0.10 mm wall 1.250 OD X 0.20mm wall Pressure handling calcs not been revisited in any major way since JT/GV/RF/PF made original estimates at the start of the tracker project other than quick sanity checks. IBL community + UK ATU made joint purchase of some 2.175mm OD CP2 titanium. This is to be delivered to RAL about now! Calcs tally with previous work. The pressure handling calcs for this smaller OD Ti do allow further wall reduction but it is not possible to manufacture at a cost we can afford Tube is obviously within a safe limit as the wall thickness has not decreased by the same factor as the OD by comparison to the 1/8” OD Ti or 316L SS the tube wall is thicker v OD! Tooling made for bending 1/8” OD 316L SS and in 2010 CP2 Ti Out of roundness-minimum bend radii calculations made for the CP2 Ti Data presented at the ATU week in Nov 2010. Tube cutting and preparation was investigated in order to deliver a cooling circuit to the exact tolerance of the drawings. Cutting equipment was purchased and tested with reasonable success. Bending of the desired tube into the cooling circuit design:

5. 5 Tube joining – TIG welding Electrode burn-out. High arc temperature required for Ti welds was causing burn-out of Cirium Tungsten electrodes. Changed to Thorium based electrodes that (normally used for Aluminium TIG welding) create a cooler arc during welding. This improved weld quality without depositing tungsten into the weld. Lower power could be used and weld and HAZ reduced. Post weld micro-cracking evident with one type of welding procedure in the machine menu. This was resolved with writing a new menu and alteration of some “hard limits” of the machine. The problem area with the Ti welding in 2010.. CP2 Ti (b) CP2 Ti butt weld successfully made,ish. Cause of faultWhy? Remidy? Helical arc caused by the arc wandering during rotation No idea other than low power control Uneven HAZAs above (hopefully) Hot spots seen in weld poolUnsure Micro cracking evidentTack welding is the wrong method/ abandon 1 st Micrographic test – X-Ray of CP2 Ti Joint (1/8” od) – not bad!

6. 6 Testing of the cooling circuit and components Hydraulic and thermal cycling tests based at RAL working fine, all welded circuits have passed this phase of testing with zero failures throughout the entire programme... Thermal Shock test work is now being looked after by Ian W – he has made drawings of the next phase of the test set up and RAL to manufacture. “Skyscan” Micro-focus CT scanning system has been used at Sheffield for rapid evaluation of 1/8” CP2 Ti tube weld samples without the traditional 2-3 week “testing house” turn round. Downside is there is ~600 hours of reconstruction work to complete! Initial reconstruction images are very encouraging. 6 Component identification and data base. Bar coding investigated – the old SCT stuff still works and is at Sheff, Lancs & RAL ready to go. Format decided upon and again ready. People keep cutting the ID’s off the circuits. This is a pain. Using sticky lables for the moment until a permanent solution decided upon.

7. Cooling: 2011 objectives: Bending of the desired tube into the cooling circuit design: 2mm bending to continue – improved tooling and a new cutting system is now being made. Production of parts for services mock up Joining of the tube 2mm tube welding & CP2 Ti work Weld head modifications for smaller Swagelok head now needs testing. Nasty chemistry to continue whilst providing useful information. JM to continue blowing chips up – relay information to Peter Phillips to distribute to the community for acceptance – link in with Swagelok US meeting in Feb. JM required here. Possible purchase of 2 nd weld system once smaller weld head proven and 2mm joining made successfully. This is a very tall order for what we have so another option may need to be pursued. We always have a nagging problem of everyone wanting to use the weld system. Testing of the cooling circuit As previous years – continue with existing tests and sign off new circuit design etc. Thermal shock tests need to be done – we’ve not broken anything yet – this is good but also worrying. In situ x-ray will be investigated to see if the same tech can be used for weld inspection. Documentation Major work needed to: 1- document what has been done in the past, 2 keep up with what is going on. It’s not much fun hence it’s not been done. My fault! Component identification will be made by either sticky labels or something posh (Cash dependent). CO2 cooling plant production C02 cooling rigs x? to continue at RAL for stave testing plans OVERALL OBJECTIVE is to be in a position to provide a complete cooling package for the ATU R&D in the lead to pre production / production / installation. 7