1. Cryogenic discussion and update 30 October 2014Neutrino platform

2. 30 October 2014Neutrino platform Neutrino Cryogenics Requirements Meeting September 23 rd and 24 th 2014 @ CERN Experiments present: ICARUS 35 ton cryostat MicroBooNe LAR1-ND LBNF Two days of discussion on cryostats and cryogenics

3. ICARUS 30 October 2014Neutrino platform CERN

4. ICARUS 30 October 2014Neutrino platform Very good results with Oxysorb (Chromium) and Hydrosorb filter All the components and mechanical assemblies were tested in LAr to verify their compatibility with our purity requirements During 3 years of underground operation lifetimes up to 15 ms have been measured Temperature uniformity over 3 years of operation < 0.25 K

5. 35 ton cryostat 30 October 2014Neutrino platform Can the membrane technique be used for large volume liquid argon cryostats: Build and operated 35 ton test cryostat Test piston purge principle (cannot evacuate the cryostat) Measure the heat load (12.5 W/m 2 ) Good pressure regulation possible (+/- 0.41 mbar over 24 hours)

6. MicroBooNe 30 October 2014Neutrino platform Installation of MicroBooNe Phase 2 is on the way Total volume 128 m 3 of liquid argon During Phase I Multiple bottom-to-top volume changes using high purity gas From air to < 0.5 ppm O2 and H2O, < 2 ppm N2

7. LAr 1 ND 30 October 2014Neutrino platform LAr 1 ND base design: membrane cryostat for 180 ton of liquid argon; Operational gas pressure: about 70 mbar Design pressure 350 mbar Maximum static heat-load: 15 W/m 2 LAr circulation pump stationed outside of argon bath (electrical noise reduction) Concrete / metal support structure Shall ullage be kept at T < 100K?

8. LBNF 30 October 2014Neutrino platform

9. Cryogenics 30 October 2014Neutrino platform First study of LAr1-ND cryogenic system

10. Open questions 30 October 2014Neutrino platform At the end of the meeting the following open points were identified: What is the maximum allowable temperature difference over the argon bath (vertically), what will be the natural stratification in such a large argon volume; What are the advantages / disadvantages of the different purification systems (active copper versus commercial available Hydrosorb / Oxysorb combination); What shall be foreseen for the cryostat ullage: Internal warm (easy feed-troughs, but outgassing); Internal cold (diminished outgassing, how to regulate the purification process, which kind of feed-troughs to be used); External warm (no outgassing in sensitive volume but cold feed through, second argon volume to be placed in experimental area; Liquid connection at bottom of cryostat (circulation pump, emptying), how to implement this safely in the cryostat Which control system to be foreseen for these systems. Easiest to equip them all with the same system, however dependable on the place the system will be installed; Long life-time purity monitors, which equipment shall be used and shall they be installed internal of the cryostats?

11. How to continue from the CERN side 30 October 2014Neutrino platform Setting up of CERN cryostat and cryogenics workgroup 2 staff 3 project associates (from Fermi, ICARUS and LAGUNA) This workgroup shall collaborate with the same kind of workgroup at this moment been set-up at Fermi Workgroup will concentrate on: 1.cryogenics needed for CERN based LAr neutrino test stands 2.technical help for the upgrade of the ICARUS experiment at CERN 3.cryogenics needed for the WA105 small and large prototype 4.cryogenics needed for the LAr-1 ND and ICARUS at Fermi 5.collaborate on the development of the cryostats and cryogenic installations of the LNBF

12. 06 March 2014 CI: Group meeting