1. Issues with variable thickness absorbers Iouri Ivaniouchenkov, RAL MICE Video Conference, 22 Jan 2003 1

2. Current proposal for the absorber with 2 thicknesses MICE Video Conference, 22 Jan 2003 2

3. Suppose we would like to change the thickness of this absorber MICE Video Conference, 22 Jan 2003 3

4. For that we have to free the absorber unit and to remove it MICE Video Conference, 22 Jan 2003 4

5. Action list to change thickness of one absorber 1.For absorber module cut all connections to: - hydrogen system - cooling system - vacuum system - power system - control system - blank off all pipes 2. Do the same operations for Flip Coils 3. Prepare a temporary support for absorber unit to be placed on 4. Dis-assemble shielding roof 5. Move absorber unit out of the cooling channel 6. Move absorber unit into a clean lab 7. Remove windows, install spacers, put windows back MICE Video Conference, 22 Jan 2003 5

6. Action list to change thickness of one absorber (part II) 8.Perform all necessary checks: - vacuum tests; - overpressure test; - check all sensors etc. 9.Move absorber back into the experimental hall. 10. Install absorber into position and seal it. 11. Connect absorber unit to all systems. 12. Perform all necessary checks for the absorber unit: - vacuum tests - electrical tests etc. 13. Repeat step 12 for at least two adjacent RF modules! 14. Put back shielding roof. 15. Cross your fingers and try to run the experiment. MICE Video Conference, 22 Jan 2003 6 Could not be easy at all !

7. Now can we make one step back and ask ourselves: Do we really need to change the thickness of hydrogen absorbers ? If answer is Yes, how to do this without breaking experiment apart ? MICE Video Conference, 22 Jan 2003 7

8. 8 LH2 Thin plastic-film walls “Thick” safety windows A variable thickness LH 2 absorber Can two outer chambers be filled with LH 2 by simply raising up the level of the liquid ? (simply an idea in its very early stage) H2

9. Use of rigid retractable flanges requires precise alignment (0.1 mm) of the surfaces to be sealed. Can we use bellows flanges instead ? Pictures from the Web-site of Palatine Precision Ltd, UK