1. Hall B Cryogenics CLAS and CLAS12 David Kashy Hall B Lead Engineer May 26, 2010

2. CLAS Cryogenic Components – Transfer line from ESR – 6 coil torroidal field magnet with service module –built by Oxford Instruments operating since 1995 – 500 liter liquid helium dewar – standard product with 2 liquid withdrawal bayonets and cold gas return – Liquid helium cooled cryo-target - capable of liquefying hydrogen, deuterium, He4 and He3 – Frost Target and 5 Tesla Polarizing Magnet – 5T Polarized Target – cooled with LHe – 4.7T Solenoid – cooled with LHe – HDIce – In development also cooled with LHe

3. CLAS Cryogenic Hardware CLAS OXFORD Torus Frost Polarizing Solenoid Cryofab 500 l Buffer Dewar 4.7 T DVCS SolenoidPhoton Target Cell 40 x 4cm Microwave Polarized Target Electron Target Cell 2.5 x 1cm 30mK FROST Target

4. Scheduled Experiments 2010-2012 Frost: Torus, Buffer Dewar, Frost Target and Polarizing Magnet HDIce/HD DVCS: Torus, Buffer Dewar and In-Beam-Cryostat Primex: No cryogenics, but keep Torus cold Two Photon Exchange: Torus, Buffer Dewar and Standard Cryotarget

5. CLAS Loads Torus: 110 Watts and 0.6 g/s lead cooling Transfer Lines and Buffer Dewar: 30 Watts Targets and Solenoids – All are of same order of magnitude ≤ 1g/s (liquefaction loads) LN2 – 7 g/s including TL

6. CLAS 12 Cryogenic Components – Transfer line from ESR – 500 liter liquid helium dewar – standard product with 2 liquid withdrawal bayonets and cold gas return – Liquid helium cooled cryo-target - capable of liquefying hydrogen, deuterium, He4 and He3 – New 6 coil torroidal field magnet with service module – New 5 Tesla Solenoid Magnet – New Distribution Can for both magnets and connection of Buffer Dewar – New Polarized Target – HDIce – In development also cooled with LHe

7. CLAS 12 New hardware Torus – WANG NMR Solenoid – WANG NMR Distribution Box

8. CLAS12 Loads Torus: 100 Watts and 0.6 g/s lead cooling (per specification note: Vendor claims less) Solenoid 70 Watts and 0.6 g/s lead cooling (per specification note: Vendor claims less) Transfer Lines, Distribution Box and Buffer Dewar: 60 Watts Targets– All are of same order of magnitude ≤ 1g/s (liquefaction loads) LN2 – ~10 g/s including TL

9. CLAS12 Load Summary Refrigeration load 230W Liquefaction load 2.2 g/s LN2 10g/s LHe Inventory 1150 liter LN2 Inventory 200 liter  Start up date April 2013  Duration 10+ years

10. Questions?