Andrei Seryi, 10/10/03, PEP-II MAC mtg.1

PEP-II IR2 alignmentPEP-II IR2 alignment

S.Ecklund, C.LeCocq, R.Pushor, R.Ruland, A.Seryi, Z.Wolf

With big help from

A.Acosta, F.Brown, R.Chestnut, A.Chupyra1, B.Dix, C.Dudley, T.Himel, D.Jensen, M.Kondaurov1, T.Lahey, B.Myers, M.Petree, J.Seeman,

U.Wienands, M.Zurawel, et al. (1 BINP)

PEP-II MAC meeting, October 2003

Andrei Seryi, 10/10/03, PEP-II MAC mtg.2

Event flow

• Motivations– IR orbit correctors show correlation with current – IR

magnets move? – Spring 2003 => tiltmeters installed on IR quads observe

motion correlated with current• SR heating vacuum chamber => expansion => push magnets

• August 2003 : decided to install new systems in IR– Hydrostatic level system– Stretched wire system– Laser tracker system

• This talk:– Data from 3 systems => reconstruction of IR magnet

motion• Next:

– Orbit motion modeling, optimization of orbit correction or feedforward. Possibly, cure the cause of motion

Consider only vertical motion. Horizontal data, and data from laser tracker are being analyzed and are not discussed in this talk.

Andrei Seryi, 10/10/03, PEP-II MAC mtg.3

Hydrostatic sensors

Stretched wire. Sensors.

Tiltmeters

LeftABackward<= e+

Andrei Seryi, 10/10/03, PEP-II MAC mtg.4

Hydrostatic sensors

Tiltmeters

Laser tracker

RightBForward<= e+

Andrei Seryi, 10/10/03, PEP-II MAC mtg.5

Left side. Stretched wire system.

Hydro sensors

Q5 Q4

Andrei Seryi, 10/10/03, PEP-II MAC mtg.6

Right side.

Hydro sensors on the raft.

Targets Laser tracker

Tiltmeters

Q5

Q4

Andrei Seryi, 10/10/03, PEP-II MAC mtg.7

IR magnet motion – “hydro” dataThe left raft motion is correlated with current(s), but not much the right raft.

Slope is changing more significantly than the center of Q5 position.

IR Motion expressed as a vertical slope (pitch) and position of the raftSlope: positive slope = end of raft closer to IP lifts up. Raft position is recalculated to the center of Q5 quad (positive position means the raft is higher).Horizontal axis => day of 2003.

Andrei Seryi, 10/10/03, PEP-II MAC mtg.8

Left side moves significantly more than the right one, the motion is correlated with current (mostly LER), is observed by hydro, wire and

tiltmeter systems, and correlates with IR orbit feedback signals

Andrei Seryi, 10/10/03, PEP-II MAC mtg.9

Left side motion is caused primarily by LER– whose

SR shines onto the left side

Left

Right

Raw data

Correlation with LER current easier to see in the moments of different behavior of LER and HER currents

Left

Right

Andrei Seryi, 10/10/03, PEP-II MAC mtg.10

Reconstruction of IR motion

• Left side moves most• Were lucky to install wire on the left side!

• Hydro system on the raft, wire and titmeters on magnets allow to reconstruct motion of magnets– Is there only common pitch of the raft and no magnet

motion relative to the raft? • Considered and rejected as unsupported by data

– Is there transverse flexibility between Q2 and Q1 that would affect wire data?

• Considered and rejected. Q2-Q1 is rigid transversely

• Shown below is a preliminary but consistent model of IR magnet motion

Andrei Seryi, 10/10/03, PEP-II MAC mtg.11

Left raft IR magnet motion model

Example of magnet position for two extremes. The raft pitch change by about 30 rad, the magnet position change by about 120 m.

Model: on top of hydro data (motion of raft as a whole) add relative motion to be consistent with wire and tiltmeters.

Most of deformation occur near Q2.

Andrei Seryi, 10/10/03, PEP-II MAC mtg.12

Left raft motion model details of the fit to wire data

Model: use common pitch of the left raft, + relative on raft motion, dependent on the common pitch, to predict and make best fit to the stretched wire data.

Measured wire data Modeled wire data

Andrei Seryi, 10/10/03, PEP-II MAC mtg.13

Left raft motion modeldetails of the fit to tiltmeter data

Model: use common pitch of the left raft, + relative on raft motion, dependent on the common pitch, to predict and make best fit to the tiltmeters data.

Measured tiltmeter data Modeled tiltmeter data

Andrei Seryi, 10/10/03, PEP-II MAC mtg.14

Left IR magnet motion model

AVI

GIF

Andrei Seryi, 10/10/03, PEP-II MAC mtg.15

Summary and next steps

• Installation of new alignment monitoring systems in IR-2 allowed to determine details of IR magnet motion

• Most of the fast (current-correlated) motion is on the left raft, due to LER SR, supposedly heating chamber near Q2

• Next step is orbit modeling and optimization of orbit correction and location of correctors. Possibly, with use of feedforward from alignment systems.

• Can this motion be cured? – Re-steer orbit? (but there are many

restrictions on orbit position…)

– Mechanical design modification?

– …