1. MICE Installation and Commissioning meeting RAL, 12 June 2007 Diffuser Oxford University

2. A re-cap on where we were, and the space constraint of placing the diffuser into the tracker solenoid bore 145mm is all we can have !! Beam direction

3. Clearance envelop for the diffuser assembly approx. 145 mm Clearance envelop for Diffuser mechanism Patch panel Tracker solenoid Iron shield Clearance gap = 250mm Patch panel Tracker solenoid Iron shield Clearance gap = 250mm The space constraint & positioning requirement for the diffuser 105 mm 163 mm from flange face Diffuser final position

4. Carousel sub-assembly – for selecting the right diffuser plate The driving system – air motors (3-off) Control & locking device Diffuser plate transport system

5. Travels some 300mm Patch panel

6. A reminder of how the mechanism works

7. The central carousel is gear driven, and allows the selected disk to be placed outside the tracker solenoid bore, waiting to be taken in

8. The inching mechanism allows the disk to be off- loaded from the central carousel and be loaded onto the disk carrier. This motion is driven by a dedicated air motor.

9. Loading and off-loading of the diffuser plates is provided by two sets of bayonets; one at the carousel and the other on the disk carrie.

10. Since the last CM meeting (CERN Feb 2007), a number of changes were made:- 1) Diameter of the lead disk. They are:-

11. Make up disk 10 thk, ID 254, OD 300 Main disk Ø254, variable thickness

15. Since the last CM meeting (CERN Feb 2007), a number of changes were made:- 1)Size of the lead disk. They are:- 2)Thickness of the disk. Each of the 5 disks has its own different thickness. They are:- 15.5mm 10 mm 7.5 mm 5 mm 1.5 mm

16. Since the last CM meeting (CERN Feb 2007), a number of changes were made:- 1)Size of the lead disk. They are:- 2)Thickness of the disk. Each of the 5 disks has its own different thickness. They are:- 15.5mm 10 mm 7.5 mm 5 mm 1.5 mm We are studying if the 1.5mm thick lead disk is structurally stable

17. Since the last CM meeting (CERN Feb 2007), a number of changes were made:- 1)Size of the lead disk. They are:- 2)Thickness of the disk. Each of the 5 disks has its own different thickness. They are:- 15.5mm 10 mm 7.5 mm 5 mm 1.5 mm 3) Planetary gears, control logic and locking mechanism have been introduced to the design to enable fine adjustment on the selection and positioning of the diffuser moving parts;

18. In existing design, the material for all the gears are Aluminium. In new design, the material for the gear teeth are changed to Stainless Steel. The SS is added carrying the gear teeth, keyed and bolted to the Al disk holders. The advantage of the change: 1.Stainless steel for the gear teeth is more wearable. 2.Gear teeth can be replaced without having to replace the whole carousel. The disadvantage: Mass increased 1kg per gear. Material changes

19. Progress & Schedule:- Detail design on the control and locking mechanism is still on-going; We are releasing some part of the diffuser for manufacturing so that we can maintain our original schedule for installing the prototype into the decoy tracker module at IC; Until we have the prototype mounted properly, it would be difficult to adjust the control and locking mechanism to achieve its required precision; We schedule to have the prototype ready by the beginning of September;