Thermal aspects Unité mixte de recherche CNRS-IN2P3 Université Paris-Sud 11 91406 Orsay cedex Tél. : +33 1 69 15 73 40 Fax : +33 1 69 15 64 70 http://ipnweb.in2p3.fr

Cooling for CLAS-DVCS => HPS ECAL Based on « Thermal design for the CLAS-DVCS calorimeter » September 2004 Copper serpentines on the thermal enclosure Flow map inside the DVCS ECAL Beam Flow split ECAL top Preamps Flow map inside the HPS ECAL => minimize the pressure drop to get low delta T° bottom NESLAB chiller RTE740 ~700 W cooling capacity@17°C 3 L/mn @ 0.5 bars

Power summary for CLAS-DVCS => update for HPS ECAL Based on « Thermal design for the CLAS-DVCS calorimeter » September 2004 The crystals are stabilized at 18°C Front plate P = 2.31W Top cover and cradle P = 5.83 W Back plate with serpentine = thermal shield Evacuation of air Circulation of cooled nitrogen at low flow Thermal components and amounts of thermal power to dissipate by cooling system The total power of this system is 86.7 W Outside temperature : 30°C with low fan air Transient cooling of crystals in some hours P = 11.5 W 53 W of heating power by electronics preamplifiers Back covers and plate P=5W Cooling panel in the center All elements in blue are cooled at 17°C minimum to obtain 18°C on crystals Convection exchange coefficient h = 7.59 W/m².K Links with outside (mother board, supports P = 5W) Radiation P = 4 W Power summary for the HPS ECAL ECAL top Preamps bottom Transient cooling of crystals in some hours P = 5.75 W 26.5 W Links with outside (mother board, supports) P = 5W Front plates P=2.3W Covers P=12.4W Radiation P=5W Total ~89W for the HPS ECAL

Schedule Unité mixte de recherche CNRS-IN2P3 Université Paris-Sud 11 91406 Orsay cedex Tél. : +33 1 69 15 73 40 Fax : +33 1 69 15 64 70 http://ipnweb.in2p3.fr

1 ECAL DVCS = 2 ECAL HPS + Vacuum chamber Still lots of things to integrate. It is not forgotten !! Alignment targets with the JLAB laser tracker Thermal sensors ….

Schedule