ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 1 Brief Status Report on Fabrication & Measurement of ATF2 Quads and Spencer’s Trip to IHEP, February 2006 By Cherrill Spencer, SLAC, for ILC-BDS weekly meeting on 28 th February 2006

ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 2 Example of one of the ATF2 quads made at IHEP

ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 3 What’s happened: February 2006 Goal was 24 fabricated and measured quads to have arrived at KEK, Japan, by 31 st March. Total order is 29 quads. All 120 trim coils have been wound By 23 rd Feb: 80 main coils been wound and 55 been potted Predicted that by today 96 coils will be ready. Core fabrication has had some problems: flame cutting of 20 quadrant pieces would have made final quadrant size too small (see photo on next slide). New steel had to be ordered: special order from distant steel mill, has taken longer than anticipated Conclusion: only 12 quads will be delivered by 31 st March

ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 4 What Spencer did while at IHEP: Feb Monitored the ongoing main coil winding Looked at main and trim coil travellers to check dimensions were within tolerance, cooling hole passage was clear, leak test, impulse test, hipotting test all been done: YES Looked at travellers to check resistance within spec: yes Looked at CMM reports on 2 cores: poletip shape still a little out of tolerance but harmonics are within tolerance, which is what matters

ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 5 Some of the 20 quadrant steel pieces that were flame-cut too small

ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 6 Magnetic Measurement at IHEP Status Custom made rotating coil being tested since mid January in the first quad. Has multiple set of windings so can buck out much of the quadrupole signal in order to measure the multipoles To measure integrated strength use a single winding – this technique known not to give best precision on quad strength. Looking for 5x10 -4 precision. Been having problem with large changes (1-4%) in the quad strength from day to day, measurement to measurement. Spencer looked for cause of these jumps: took lots of temperature data, timed with the rotating coil data. Varied some conditions deliberately.

ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 7 First ATF2 quad & rotating coil measurement apparatus at IHEP, February 2006

ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 8 First ATF2 quad on measurement set-up at IHEP

ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 9 Quad integrated strength data plotted with temperatures of the steel poletip & rotating coil Measurement number not same as time passed.

ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 10 Quad integrated strength (b2) well correlated with temperature of the rotating coil

ATF2Quad Fab & Measurement Status Cherrill Spencer 02/28/06 11 Looking for cause(s) of quad strength jumps Considered following possible causes: –Unstable power supply –Overshoot of current when ramping up to set point –Temperature variation of rotating coil –Temperature variation of steel core –Movement of magnet on its not-tied down support –Fringe fields from nearby magnets –Electronics that process the voltage signal from the rotating coil Put Hall probe in aperture, compared its data with rot.coil Conclusion: faulty MetroLab voltage integrator: to be confirmed by switching in a different MetroLab. Waiting to hear results of switching MetroLabs from IHEP Other issues to be resolved: standardizing to 50 amps; multipole values at various currents