1. ATF control system, N. Terunuma

Sub-system development has following two phases;
  1. R&D phase
    It is independent from the ATF control system.
  2. Operation phase
    It must be integrated into the ATF control system.
For new low-level control functions, e.g. movers, BPMs , laserwires, each sub group has a responsibility .

At high level, Beam tuning group led by S.Kuroda has a responsibility, where Lucretia, SAD and MAD should work by switching.
Note: Lucretia is used for optics calculations in the flight simulator. We would like to ask Glen for explanation of Lucretia.

We need documentation for all the systems .

Q : Sub group develops low level. High level such as BBA analysis package will be talking to low levels and Vsystem. It has an interface to data base. Is it right?
A : In a case of tuning with MATLIB, V system will start up tuning process and call MATLAB as calling to EPICS. V system works as GUI interface.
Q : BBA package can work stand alone, Is it OK?
A : It depends on the level. if access to the hardware, it should be integrated in Vsystem. if not, it is OK for stand alone.
Q : If the stand alone process accesses to movers, BPM, it needs to run on Alpha?
A : No, it should run on Linux where the ATF control system is implemented.

Summary

  1. Vsystem should integrate flight simulator (MATLAB) with;
  2. Beam tuning group must have a responsibility of high level control functions, where the flight simulator is one of applications.
  3. Each sub group has a responsibility of low-level control functions such as movers, BPMs, laserwire, FONT .

2. Bend magnet status, C. Spencer

Measurements of three DEA dipole magnetic fields have been done with stretch wires and hall probes at IHEP.

Excitation "curve measurement" was done for a range of 70-180A. The linearity is good for 3 bends.

Q ; How did they calibrate the stretched wire system?
A : I think that its performance has been verified with superconducting Q magnet measurements.
Q : Didn't they use the hall probe data to calibrate stretched wire system? If so, stretched wire data and hall probe data naturally agree each other in excitation curve measurement.
A : Stretch wire is the first measurement. Since it is absolute measurement, no calibration is needed.
C : We (KEK) think stretched wire system needs calibration in order to check the speed of the wire movement, the step width of the movement, and so on.
Measurement results of DEA no.3 : B(x)-B(0) v.s. X plot in page-13 was fitted to 4th order of polynomials, where the coefficient of x2 corresponds to sextupole/dipole amplitude ratio. Here the terminal side is positive x. Coefficient of x2 was obtained as 2 x 10-4, which is less than the tolerance value 2.5 x 10-4.

in page-14, at different y-values : coeffi. v.s. y gives skew-Q coefficient.

IHEP contract has been extended to end of November .

Q : Did IHEP use the alignment base ?
A : I think so.
Q : It is not clear. You should check it. If not, we have to think how to check the precision of position of the alignment reference plates.
A : Position can be checked mechanically. Precision of mechanical measurement is good enough.
Q : In the distribution of [BL(x)-BL(0))]/BL(0), the peak position has an offset from X=0 by about 2mm. Can you explain why?
A : New measurement ( on last Friday) has no offset.
Q : Why do the first measurement and the second measurement give different results?
A : I do not know, and they do not know either at IHEP.
Q : This might be caused by bad reproducibilty in measurement.
Q : Although you said the field variation is quite small around X=0, it depends on the tolerance for the good field region. Do you know the definition of the good field region?
A : No.
Q : Who knows?
A : I(Mark) will try to figure it out from the tolerance for the sextupole component.
C : the offset may be caused by coil-connection .
Q : Are there data as a function of z ?
A : No, but I will ask them for the data.

3. Comments, M. Masuzawa

She analyzed stability/reproducibility on DEA003 data which has been received on 11/10. Since Hall probe measurement took 30 min. for -2cm to x=0, there may be drifts. Power supply may have very big drift.
Q : Where is the stability, measurement system or magnet itself?
A ; measurement system.
Q : What is the next step ?
A : ask IHEP for the stability.
Q : Can KEK measure the magnetic field ?
A : No, since there is no system at KEK,
C : The sextupole components (2 x 10-4 ) looks OK, where the setting accuracy is 50um in x and error of gap is 1/1000 inches for 3 bends.
A : No, we can not tell that it is satisfied with tolerance for the measurement errors.
Q : What is future option ? direct ship or another measurement ?
A : We extended the contact by end of this November, So, we can ask them for new measurement.
Q : What is the schedule of magnet installation?
A : The installation will start in 7 January.
We would like to see the reproducibility of position measurements and multiple measurements at the same points. Two different data at x=0 may be measured before/after lunch time, when the power is switched off usually at IHEP.
C : I(C.Spencer) would like to ask Sugahara-san for instruction of additional measurements at IHEP.
A : Yes,
R. Sugahara prepared two slides to show a beam orbit in the DEQ-magnets of B5FF, B2FF and B1FF, where the sagittas are 3.822, 2.312 and 4.122mm. respectively.

4. Status of QC3 and sextupole magnets, C. Spencer

QC3 : The button method is not enough to reduce 12 pole component.

Sextupoles : more cooling was added, so it should be OK to be installed at LAPP.

Q : Do you understand why the button method did not work ?
A : I thought that 12 pole component was generated as an end effect. However, it may be caused by shimming for changing hyperbolla curve of field lines.

5. KEK site meeting

Concrete shields : the bid was completed on 20 November. So, ceiling, side-wall shields will arrive at the same time by end of January,2008 .

New floor level has been measured on October and November, i.e. two with one month interval, where concrete shields were installed. No significant variation was observed.

The floor level varies from 0mm (normalized) at y=0m, -8mm at y = 50m and -2mm y = at 60-70m, where the new floor starts at y=0.