1. MICE Hydrogen System Design Tom Bradshaw Iouri Ivaniouchenkov Elwyn Baynham Columbia Meeting June 2003

2. MICE Cryogenic Components: Decay Magnet – part of beam line – early installation and commissioning. Will have its own refrigerator Implies 9 cryogenic modules: –3 x Hydrogen absorber and Focusing coil pair –2 x Spectrometer coils –2 x Coupling coils –Scintillating fibre detector cryostat

3. MICE Stages Step 1Decay magnet + Sci-Fi Step 2plus spectrometer Step 3plus spectrometer Step 4 plus absorber/focus + hydrogen Step 5 plus coupling absorber/focus + hydrogen Step 6plus coupling absorber/focus + hydrogen Spring 2006 2007  This implies a modular design for the absorber hydrogen system

4. Basic Layout Spectrometer Absorber/Focus Coupling Absorber/Focus Coupling Absorber/Focus Spectrometer Decay Magnet SciFi Detector Powered valve Gate valve Relief Valve 4K 14K Return Etc…. Compressors Gas Store Cold box 4K 14K Refrigerator

5. Hydrogen Design - Principles What we are trying to do in the design is: Make it truly failsafe and passive – no active intervention is required to get the hydrogen out of the system in the event of a problem. Minimise the amount of hydrogen. Minimise the volume that has to be considered to be a hydrogen area. Make it modular to allow for staging. Minimise interactions between the absorbers to keep the system simple and reduce consequential faults. Prove we can do it for a neutrino factory

6. Hydrogen Design - Description Baseline Have gas tanks outside the experimental area piped in – Iouri will show layouts in talk tomorrow. Design is passive. Any emergency relief venting is through evacuated buffer volume – volume of this TBD but may just be a large diameter pipe. Helium purge may be preferable to nitrogen because of sludge and heat capacity issues. Have an igloo around each of the hydrogen modules vented through the roof – layouts TBD because it is complicated by several issues.

7. PP VP Vacuum pump Bursting disk Pressure relief valve Valve Pressure regulator Pressure gauge 18 K He to Compressor via Radiation shield 14 K He from Cold box Liquid level gauge LH 2 Absorber Vacuum Vacuum vessel LHe Heat exchanger 12 litre Buffer tank Hydrogen flow and safety system Internal Window 70 K Safety window H 2 Gas bottle P P Fill valve Hydrogen tank Volume: 11 m 3 Pressure > 0.1 bar Vent outside flame arrester He / N 2 Purge system Non-return valve Vent outside flame arrester Vent valve 1.7 bar 2.1 bar H 2 Detector P P P P Evacuated vent buffer tank Volume: VP P X 2 VP Version: 09/06/2003 Hydrogen module enclosure (igloo) H 2 Detector Ventilation system Vent outside flame arrester

8. Hydrogen Storage – an Option Hydrogen storage at STP will require three x 11m 3 Vessels  Possibly manageable for MICE but not for a neutrino factory! Alternative storage solutions being investigated – use of metal hydrides.

9. Hydrogen storage Commercially available – designs for automotive and fuel cell use Absorbtion (exothermic) and release (endothermic) controlled by varying temperature Large “compression” factor e.g. Ergenics ST-90 (pictured) 61x30x7.6 cm stores 2550 litres in a volume of 13.9 litres factor of 183 Energy research unit at RAL is conducting a small feasibility study JSW Unit Ergenics Unit

10. Cooling power Requirements Absorbers 50W per module at 14K (He flow 2.4 g/s ΔT=4K) (MAC Estimate – any advance ?) Focus Coils4K14KLeads 5.2W22W0.18 g/s From M Greens paper but need new estimates based on current designs – Any thermal models ? Baseline requirement is for : In process of clarifying refrigeration requirements so input is needed !

11. END