Marco Statera NA62 - GTK working group meeting 5-4-2011 GTK gas cooling system Marco Statera NA62 - GTK working group meeting 5-4-2011

From test bench to final design nitrogen from a bottle cooled by a liquid bath open system manual regulation of the flow FINAL DESIGN closed circuit of nitrogen zero boil off automated regulation of the flow remote control GTK working group meeting 5-4-2011 Marco Statera

GTK working group meeting 5-4-2011 Marco Statera The working principle cold nitrogen gas from a liquid bath The liquid bath keeps the temperature constant (pressure is regulated) and is a gas source closed circuit: nitrogen gas must be cooled down A cold head reliquefies the returning nitrogen the driving force of the flow is the pressure of the vessel a regulating valve controls the flow GTK working group meeting 5-4-2011 Marco Statera

GTK working group meeting 5-4-2011 Marco Statera Configuration One bath and three cooling lines PRO CONS - 1 cryostat - crosstalking of the flows - length of the lines (≈20 m) Three separate baths and cooling lines - independent cooling flow control - more spare parts - shorter lines (5 m) - flexible configuration GTK working group meeting 5-4-2011 Marco Statera

Scheme of the zero boiling off system READ GTK temperature, liquid level dewar pressure coldhead temperature CONTROL regulating valve motor gas output valve (ON/OFF) coldhead heating OPTIONAL GTK in/out gas temperature flow meter GTK working group meeting 5-4-2011 Marco Statera

Thermal balance LH coolpower 140T one stage 140W@80K SOURCE HEAT LOAD - W cryostat 30 4 feedtrhough 40 1 regulating valve 10 10 meters line (NEXANS) 5 GT TOTAL 125 LH coolpower 140T one stage 140W@80K lower temperature <15 K cooldown time to 20 K <55 min LH 120T GTK working group meeting 5-4-2011 Marco Statera

Control and interlock concept The control and interlock must be HW: LabView stand alone or user friendly PLC normal operation different logic for different status: i.e. standby - GTK on – etc keep the dewar pressure and control the flow by the regulating valve regulate the GTK temperature avoid too low temperature avoid thermal shocks emergency the interlock sets an allarm the gas can be warmed by turning off the cold head and turning on the heater the system still controls the regulating valve At the end of the emergency the normal operation can be recovered. Some nitrogen may be lost, the liquid bath is a reserve of nitrogen. GTK working group meeting 5-4-2011 Marco Statera

GTK working group meeting 5-4-2011 Marco Statera Costs CUSTOM CRYOSTAT 10 K€ COLDHEAD COMPRESSOR CABLES (4.5 m) 14 K€ CRYOGENIC LINES (5 m + 5 m) REGULATING VALVE 4 FEEDTHROUGH 11 k€ LIQUID NITROGEN SENSOR CONTROLLER 2 K€ OTHER SENSORS AND HEATERS GUESS QUOTATION (INFN) GTK working group meeting 5-4-2011 Marco Statera

GTK working group meeting 5-4-2011 Marco Statera Conclusions coolig system defined three separate systems closed circuit zero boil off control and interlock concept total costs 40 k€ per system (plus VAT) total 120 k€ + 40 k€ (spare) time schedule cryostat ≈12wks cryogenic line: 8 wks Installation: tbd GTK working group meeting 5-4-2011 Marco Statera