IHEPTrip Cherrill Spencer 12/20/05 1 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 20 th December 2005

IHEPTrip Cherrill Spencer 12/20/05 2 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 31 st 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

IHEPTrip Cherrill Spencer 12/20/05 3 ATF2 quadrupoles : QEA-D32T180 Spencer’s activities during trip to IHEP, 6 th -14 th 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 21 st Dec. Detailed discussions of POISSON 2D model: shows inefficiencies Observe Magnet Measuring Laboratory; see drawings of new rotating coil

IHEPTrip Cherrill Spencer 12/20/054 3 ). Detail of coil 3. Coil manufacturing NOT FINAL COIL DRAWING: DO NOT USE

IHEPTrip Cherrill Spencer 12/20/05 5 Trim coil winding form (left) and main coil winding form set-up on winding machines

IHEPTrip Cherrill Spencer 12/20/05 6 IHEP film potting apparatus (left); Dr Xuwen Dai measuring dimensions of first trim coils

IHEPTrip Cherrill Spencer 12/20/057 1). Overview of general assembly: QEA-D32T General Assembly NOT FINAL DRAWING. DO NOT USE 32mm bore 180mm core length 47 turns per water cooled coil Max gradient 55 T/m

IHEPTrip Cherrill Spencer 12/20/05 8 First quad’s core before poletips been EDM’d; IHEP’s new EDM machine

IHEPTrip Cherrill Spencer 12/20/05 9 First core after all machining finished, in the IHEP Machine Shop.

IHEPTrip Cherrill Spencer 12/20/05 10 ATF2 quadrupoles : QEA-D32T180 First core’s poletip measurements HERE ARE THE MEASUREMENTS OF THE FIRST CORE: Diameters at 4 different Z in mm To be compared with 32 +/- 0.05mm What matters is the spread of the values — their spread is less than the +/-0.05 tolerance It is OK that the absolute diameters are a little larger than 32mm Four spaces between adjacent poles, measured at 3 different Z, mm: 10.27, 10.26, (between poles 1 and 2) 10.23, 10.23, (between poles 2 and 3) 10.21, 10.21, (between poles 3 and 4) 10.26, 10.26, (between poles 1 and 4) To be compared with / All values meet the tolerance.

IHEPTrip Cherrill Spencer 12/20/05 11 IHEP’s ATF2 QUAD team (left); view from my Guest House Room

IHEPTrip Cherrill Spencer 12/20/05 12 My IHEP liaison/escort/guide: Dr Jianbing ZHAO at the Great Wall near Beijing

IHEPTrip Cherrill Spencer 12/20/05 13 At the Summer Palace (note the frozen lake) and the Tiananmen Gate to the Palace Museum

IHEPTrip Cherrill Spencer 12/20/05 14 Next steps: late December ’05- January ‘06 First core being measured on a CMM- results will be sent out Hollow conductor should arrive today (20 th 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 3 rd /4 th January amongst IHEP, KEK and SLAC to inspect the cut coil via TV If first coil OK they will continue to wind coils By ~ 9 th January - first magnet will be assembled By ~ 25 th 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.