DETECTOR COOLING PROJECT

1. DETECTOR COOLING PROJECT Status and Plan for WP#1 P. Petagna – September 30th2009 (update of the slides prepared for June 17thAugust 19th meetings and never officially presented)

2. WP1 –On-detector leak search and repair • PROPOSED WORKPLAN: • 1 - Applicable methods for leak detection and finding (Definition / Standardization) • 1.1 Pressure drop • 1.2 Sniffers • 1.3 Endoscopes • 1.4 Radiography/Penetrating liquids? • 1.5 “Exotics”? • 2 - From “Leak Rate” to “Fluid Loss” (Definition / Standardization) • 2.1 Systematic analysis and classification of existing literature on the subject • 2.2 Design of a test bench and execution of ad-hoc tests on calibrated leaks on particular configurations of interest • 3 - Understanding “in situ leak repair” • 3.1 Applicability of “standard” repairs to “accessible leaks” (i.e. outside detector) • 3.2 Prosecution of the RAL analysis of existing methodologies of “inaccessible” leak repair • 3.3 Deep understanding of chemical implications of the different techniques (fluid compatibility, radiation hardness, process control, risk of clogging, needs for subsequent cleaning…) • 4 - Tests • 4.1 Construction of a test bench (real-scale mock-up of typical non accessible circuits) and execution of ad-hoc tests on calibrated leaks for the technique(s) possibly selected.

3. WP1 –On-detector leak search and repair STATUS: 1 - Applicable methods for leak detection and finding (Definition / Standardization) Still collecting and organizing information. PH/DT in the process of purchasing: 1 MKS Baratron absolute pressure capacitance manometer (120AA-15000RBJ, range 2x10-4 ÷ 15 bar) http://www.mksinst.com/product/category.aspx?categoryID=72 1 Adixen Hydrogen leak detector H2000 plus (sensitive to 5x10-7 mbar l/s leaks) http://www.adixen.com/adixen_avt/download/docs/prod/doc1prod77.pdf?nocache=1254262740 1 SKF video endoscope TKES 1 http://www.mapro.skf.com/pub/pds/TKES1_datasheet_f.pdf (Total investment : 20 ÷ 25 kCHF) Discussion ongoing with ScuolaSuperioreS.Anna (Pisa) for a co-tutored PhD thesis on an untethered miniaturized device to explore inaccessible regions of small diameter pipes (example of larger scale similar concept: http://www.iris.ethz.ch/msrl/research/special/cern.php ). The thesis could be funded by the Italian Institute of Technology within the platform for micro-robotic development.

4. WP1 –On-detector leak search and repair STATUS: 2 - From “Leak Rate” to “Fluid Loss” (Definition / Standardization) Literature analysis still to be completed but a lot of information already collected and organized by P. Tropea. Many of the available relationships allow to link pressure decay measurements to an estimated equivalent size of the defect. For example for Nitrogen gas one finds: where: d is the equivalent round hole diameter of the defect (m) Po is the initial pressure (Pa abs) P is the mean pressure (Pa abs) dP is the pressure drop (Pa) over the time span dt (s) ρo is the density of nitrogen at Po (kg/m3) V is the volume of the system under test (m3) Direct measurements on “calibrated” leaks vs. measured losses of C3F8 and C6F14 would be extremely useful and are already planned. The refurbishment of a C6F14 chiller recuperated from CMS to be used in the new PH/DT cooling lab is ongoing and will allow easy measurements on C6F14 . C3F8losses will be most likely measured on a non-circulating pressurized system, but the availability of the fluid and of specific components might be critical. Help from EN/CV-DC + ATLAS will be sought.

5. WP1 –On-detector leak search and repair STATUS: 3 - Understanding “in situ leak repair” Documentation from Jason Tarrant received. Two existing techniques available: In the late 1980’s NNC ltd (presently Amec, see http://www.amec.com/sectors/nuclear/new_build/lab_services.htm) developed sealant products called “ZORIC”: water-based blends of mineral clay and epoxy resin. Apparently tested with some success in the late 1990’s also at CERN for standard water piping: need some “archeological search” to find some documentation (some traces found athttp://st-div.web.cern.ch/st-div/meetings/sttc/10.htm ). Amec experts very skeptical for use in our application because of the need of water as a carrier, the size of pipes and manifolds, the low operational temperature. More recently, at Savannah River National Lab (USA) a specific sealant for WATER-BASED applications has been investigated with some success: this is “Seal-up” by Blue-Magic (http://bluemagicusa.com/bluemagic/seal-up-page.pdf ). Principal components are sodium silicate (“liquid glass”) and copper fines (10% wt max). Complete chemical and morphological analysis performed. Radiation hardness verified. Can be used without water? More studies on this product…

6. WP1 –On-detector leak search and repair • STATUS: • 4 – Tests for repair • To be discussed later on.

7. WP1 –On-site leak search and repair RESOURCES: Preparing White Paper PH budget request for next year, plan to include some 10÷20 kCHF on top of the investment money on this subject. Participation from the experiments will be asked when coming to full-scale simulation of typical circuits. Manpower: Availability of 1 Technician from PH/DT partially delayed (one part time technician already available, one more will be soon pending completion of present activities on ToTEM and ALFA) Part-time activity for “Eng-Staff 2” in PH/DT + P. Petagna: from late October Help and support from “gas” section agreed Some time from one PH/DT fellow: from late October Collaboration with TE to be discussed MAIN WEAKNESS: Most likely M. Tavlet will not be available.