MICE Target Status Chris Booth Sheffield 10 th May 2006

Chris BoothUniversity of Sheffield 2 Focus of recent work has been assembly tests at RAL 24 th -28 th April. –Review of components –Results of tests –Preliminary follow-up plans

Chris BoothUniversity of Sheffield 3 Components Stator body Ceramic tube Glass readout tube Target shuttle Ceramic bearings Electronics Frame, jack, bellows, gate-valve

Chris BoothUniversity of Sheffield 4 Stator Micro-surgery on Manchester body has allowed insertion of ceramic tube! Tolerances around ceramic slightly tight. We have learned how to make all components for future stators in house.

Chris BoothUniversity of Sheffield 5 Ceramic tube Test flanges & dummy stator built at RAL. Indium vacuum seals tested. Pronounced satisfactory!

Chris BoothUniversity of Sheffield 6 Optical readout enclosure Quartz glass tube and flange procured. Flange machined, tube fixed with cryostat cement.

Chris BoothUniversity of Sheffield 7 Shuttle Oxford agreed to assemble shaft, target, alignment fin, stop, magnets, readout vane (see picture) – many thanks! Magnets, readout vane supplied by Sheffield. For prototype, shaft produced from steel tube rather than titanium. Assembly cleaned in Oxford, delivered direct to RAL.

Chris BoothUniversity of Sheffield 8 Titanium target Steel shaft Alignment fin Stop Magnets Optical readout vane

Chris BoothUniversity of Sheffield 9 Ceramic bearings Slot for alignment fin Hole for alignment pin

Chris BoothUniversity of Sheffield 10 Control electronics Cards now rack- mounted. Extensive tests with prototype drive. Several hours pulsing at 0.3 Hz (10 A). Some reliability & noise problems to be addressed.

Chris BoothUniversity of Sheffield 11 Bellows

Chris BoothUniversity of Sheffield 12

Chris BoothUniversity of Sheffield 13 Indium seals Ceramic bearings

Chris BoothUniversity of Sheffield 14 Beam pipe Gate valve Bellows Drive mechanism Support frame

Chris BoothUniversity of Sheffield 15 Assembly test: April First time many parts came together: –Stator first connected to electronics 20 th –Glass readout tube assembled 21 st –Target shuttle finished morning of 24 th –Some RAL parts and flanges not previously assembled.

Chris BoothUniversity of Sheffield 16 What did we learn? 1.Glass tube is very fragile! –Broken near metal flange. –Ground down and re-glued – vacuum tested ok. –New crack when tightened down onto full assembly. –Covered in epoxy! Amazingly, this appeared to seal ok!

Chris BoothUniversity of Sheffield 17 2.Target shuttle was distorted –Slot cut along thin-walled tube to take alignment vane caused shaft to distort. –Vane was twisted and slightly off-axis at one end. –Would not pass through ceramic bearing. –Slot & hole in bearing machined out to allow shaft and vane to pass. –Some play and roughness, but movement satisfactory.

Chris BoothUniversity of Sheffield 18 3.Indium seals did not work! –Despite success with test pieces, could not pump down below 3  10 –3 mbar. –Flanges found to have too large diameter and chamfer; rebates incorrect so inadequate closure of seal. –Attempts to seal with extra indium. –Only partial improvement. –Prevented vacuum quality checks with mass spectrometer.

Chris BoothUniversity of Sheffield 19 4.Temperature sensitivity –Operation of drive (power-off to park position) caused deterioration in vacuum. –Chilled water cooling (12°C) also worsened vacuum. –Partial recovery on return to ambient temperature. –Movement of ceramic tube disturbing (imperfect) seal?

Chris BoothUniversity of Sheffield 20 5.Optical readout block did not fit –Insufficient space for readout block around glass tube when drive in raised position. –Large guide flange removed – appears not to be necessary. –Flange could also be machined down to allow space. 6.Extremely difficult to align optics –Higher refractive index of quartz tube? –RAL restrictions on use of laser in hall.

Chris BoothUniversity of Sheffield 21 Solutions 1 & 6 Replace glass tube with steel plus flat glass windows –Robust, much simpler optics. –Redesign optical mounts to allow off-line alignment. 3 & 4 Flanges for indium seals to be re- ground or re-made –Vacuum and temperature tests will be performed at RAL.

Chris BoothUniversity of Sheffield 22 2 Oxford redesigned target shuttle –Target, shaft, stop, alignment fin machined out of single piece of titanium. –Cross-shaped cross-section. –Strong, no tendency to twist. –Only magnets and readout fin to be added. –New (or modified) ceramic bearings will be required – design to allow insertion of shaft through lower bearing for easier assembly.

Chris BoothUniversity of Sheffield 23 Conclusions(1) Still digesting results of week before last! Despite problems, a lot was learned. Practical details of assembly tested for first time. Learned what does, what doesn’t work. Improved design of major components (optical windows & readout mount, target shuttle). No proper vacuum tests. No reliability or vibration tests. Review (with ISIS) 23 rd May.

Chris BoothUniversity of Sheffield 24 Conclusions(2) Parts (flanges etc) now in Sheffield for full system tests under vacuum. Will repeat assembly in hall. Will conduct reliability tests in Sheffield, then in assembly hall. Will not be able to install in ISIS for June – must perform thorough off-line checks to demonstrate readiness for October access. High-current driver electronics should be ready mid-summer (was not planned for June).