Report on my December 2005 Trip to IHEP, Beijing to Monitor Fabrication of ATF2 Quads

IHEPTrip Cherrill Spencer 12/20/05

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Report on my December 2005 Trip to IHEP, Beijing to Monitor Fabrication of

ATF2 Quads

By Cherrill Spencer, SLAC, for ILC-BDS weekly meeting on 20th December 2005


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ATF2 quadrupoles : QEA-D32T180 Recap on Activity from June – November 2005

• Are 8 quadrupoles in the extension of the ATF extraction line• Are 6 quads in matching section of ATF2 beamline• Are 14 quads in final focus section of ATF2 ( aside from QF1&QD0)• Decided an existing KEK quad called the TOKIN 3390 (“QB4” style) would

be basis of the design for the 28 ATF2 quads listed above.• Contract signed in early July with the Magnet Shop of the Institute of High

Energy Physics (IHEP) in Beijing, China to make new drawings and fabricate 29 quads (1 spare) by March 31st 2006.

• July-Sept: Spencer wrote very detailed specifications for this quad, new name: QEA-D32T180. IHEP drew new drawings for all parts and assemblies. Mostly approved in late September.

• Sept-Oct: Spencer continues negotiating changes in fabrication processes and materials to accommodate capabilities of IHEP magnet shop and availability of materials, so tight schedule can be met.

• Mid-Late October: IHEP designing and fabricating coil winding forms• October-Late November: IHEP machining first magnet’s 4 steel core pieces• Hollow copper conductor delivery delayed by ~ 1 month to December 20th


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ATF2 quadrupoles : QEA-D32T180 Spencer’s activities during trip to IHEP, 6th -14th Dec ‘05

• Observe completed main and trim coil winding forms• Observe and inspect coil winding shop• Inspect first 4 wound trim coils: size, resistance and inductance OK• Observe and inspect coil potting shop• Observe the brand new Electric Discharge Machine (EDM)• Inspect 4 quadrants of the first quad’s steel core: before EDM’ing of

the hyperbolic-shaped poletips• Assembled core’s 4 poletips machined over the weekend• Toleranced dimensions near the poletips measured with micrometer• All toleranced dimensions are within tolerance (see later slide)• Detailed discussions of OPERA 3D computer model of quad:

appears model not predicting accurately. Spencer will try modelling it with our own new OPERA program which is due to arrive 21st Dec.

• Detailed discussions of POISSON 2D model: shows inefficiencies• Observe Magnet Measuring Laboratory; see drawings of new rotating coil

IHEPTrip Cherrill Spencer 12/20/05 4

3 ). Detail of coil

3. Coil manufacturing NOT FINAL COIL DRAWING: DO NOT USE


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Trim coil winding form (left) and main coil winding form set-up on winding machines


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IHEP film potting apparatus (left); Dr Xuwen Dai measuring dimensions of first trim coils

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1). Overview of general assembly: QEA-D32T180. 4. General Assembly

NOT FINAL DRAWING. DO NOT USE

32mm bore

180mm core length

47 turns per water cooled coil

Max gradient 55 T/m


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First quad’s core before poletips been EDM’d; IHEP’s new EDM machine


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First core after all machining finished , in the IHEP Machine Shop.


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ATF2 quadrupoles : QEA-D32T180First core’s poletip measurements

HERE ARE THE MEASUREMENTS OF THE FIRST CORE:• Diameters at 4 different Z in mm• 32.17 32.13 To be compared with 32 +/- 0.05mm.• 32.15 32.12 What matters is the spread of the values—

their spread is less than the +/-0.05 tolerance• 32.15 32.12. It is OK that the absolute diameters are a • 32.16 32.14 little larger than 32mm

• Four spaces between adjacent poles, measured at 3 different Z, mm:

• 10.27, 10.26, 10.26 (between poles 1 and 2)• 10.23, 10.23, 10.23 (between poles 2 and 3)• 10.21, 10.21, 10.21 (between poles 3 and 4)• 10.26, 10.26, 10.27 (between poles 1 and 4)To be compared with 10.24 +/- 0.03. All values meet the tolerance.


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IHEP’s ATF2 QUAD team (left); view from my Guest House Room


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My IHEP liaison/escort/guide: Dr Jianbing ZHAO at the Great Wall near Beijing


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At the Summer Palace (note the frozen lake) and the Tiananmen Gate to the Palace Museum


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Next steps: late December ’05- January ‘06• First core being measured on a CMM- results will be sent out

• Hollow conductor should arrive today (20th Dec)• Five main coils will be wound and potted• First coil will be cut in half so we can inspect the turn’s

pattern and quality of impregnation of the epoxy• Video conference on 3rd/4th January amongst IHEP, KEK

and SLAC to inspect the cut coil via TV• If first coil OK they will continue to wind coils• By ~ 9th January - first magnet will be assembled• By ~ 25th January first magnet will be measured at IHEP

by new, custom designed rotating coil.• If first quad looks OK production will be given go-ahead.

Documents

Report on my December 2005 Trip to IHEP, Beijing to Monitor Fabrication of ATF2 Quads