AC/GEO mole measurements Based on outcome from meeting 24/11 2005 and Installation data

Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 1

AC/GEO mole measurements

Based on outcome from meeting 24/11 2005

and Installation data

Elena WildnerJ. Beauquis, L. Bottura, M. Buzio, D. Missiaen, P.

Winkes


Background1. There was a systematic difference of the data for the two

measurement moles (AC from AT/MTM and GEO from TS/SU) for the geometric axis of the SSS of ~ 0.25 mm in the vertical plane, integrated over all measurement points for magnets 177, 154, 249, 349, 49

2. SSS 14, 50, 74, 160, 162, 174 and 180 (0.2-0.3 mm) have a similar problem

3. The observed systematic difference depends on the mole pair used

4. For magnets 49, 249 and 349 the AC mole was used for the install pack

5. For magnets 177 and 152 the GEO mole was used in the absence of the AC mole.

6. This triggered an investigation of the calibrations


List of Actions made 1. Calibrations of the moles used for the batch (AC4,

GEO13)

2. The GEO mole 13 was found to have an offset of -0.12 mm. The GEO mole has been repaired, not necessarily drift, uncontrollable mechanical effect

3. The AC mole has been re-calibrated the calibration difference was 0.09 mm.

4. Cross calibration is going on between the two mole:

1. Results are not yet conclusive. Measurement conditions need to be better controlled.

2. A better test bench will be set up 3. The center of a calibrated tube will be measured in

the metrology lab (3D measurements, 20 precision), the AC-mole and the GEO-mole will be used to measure the center


Calibrations checks, Future I

The operator software will be changed. A warning will be given if the integrated (over the SSS) difference of the two mole is > 0.2 mm. In this case both moles will be changed and the magnet re-measured. The old moles will go for calibration and maintenance. May be iterated. Concerns 10% of the measurements.

The AC mole will always be the reference for the GA if the AC mole data is correctly measured. To calculate GA with AC mole was originally decided due to the fact that only one measurement made for both magnetic and geometric axes. The geo-mole is there to cross check. The GEO mole is used to check that the AC mole is not completely out which happens from time to time. Extensive efforts have been made to certify the AC-mole: AC mole 6 is used in the reference:

Magnetic and mechanical axis of Short Straight Sections in the arcs: a summary of the results of the first 111 warm and cold series tests. L.Bottura et al. Note 373

The magnet will always be measured using both moles. Both measurements will be given in the shift tool.

In addition: weekly calibrations and checks of both moles will be made, and tracked in the data base. A common calibration bench will be set up.


Other checks, saw tooth

1. For the SSS, there are no important saw tooth phenomena. This is only a problem for dipoles.

2. The saw tooth will be checked. 1. The distance to the Leica will be taken into account

in the plots (only information, no recalculations).2. TS/SU will check the influence on the GA-calculation

of weighing of the measurement points. From this a decision will be taken.

3. If the saw tooth is constant over the measurement, re-calibration or re-measurement may be required. I don’t agree with this. It can also be a problem of relocation of the station 2 wrt to station 1


Statistics, difference GEO-AC, point by point/integrated

dx average

dx stdev

dz average

dz stdev

0.00 0.09 -0.09 0.10

dx average

dx stdev

dz average

dz stdev

0.00 0.02 -0.10 0.08

Statistics, difference GEO-AC, point by point

Statistics, difference GEO-AC, integrated

dx max dx min dz max dz min

0.65 -0.41 0.42 -0.53

3 sigma tail: 37 points h, 39 points v

3 sigma tail: no points

dx max dx min dz max dz min

0.13 -0.05 0.14 0.29


Statistics, histogram for individual points, interpolated

Distribution of the mechanical axis difference (GeoMole -AC Mole) over 8635 individual measurements (GeoMole linearly interpolated)

1

10

100

1000

10000

100000

-0.6

to

-0.5

-0.5

to

-0.4

-0.4

to

-0.3

-0.3

to

-0.2

-0.2

to

-0.1

-0.1

to

0.0

0.0

to 0

.1

0.1

to 0

.2

0.2

to 0

.3

0.3

to 0

.4

0.4

to 0

.5

0.5

to 0

.6

0.6

to 0

.7

0.7

to 0

.8

Bin range [mm]

N. of

indiv

idual data

poin

ts

Horizontal difference

Vertical difference

= -0.27 to +0.27 mm

= -0.40 to +0.21 mm


Diff GEO-AC vertical plane

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

20-Oct-2004 09-Dec-2004 28-Jan-2005 19-Mar-2005 08-May-2005 27-Jun-2005 16-Aug-2005 05-Oct-2005 24-Nov-2005

meas date

Dif

f [m

m]

AP1_DZ

AP2_DZ

Statistics of difference GEO-AC


Diff GEO-AC vertical plane

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

08-May-2005

28-May-2005

17-Jun-2005 07-Jul-2005 27-Jul-2005 16-Aug-2005

05-Sep-2005

25-Sep-2005

15-Oct-2005 04-Nov-2005 24-Nov-2005

meas date

Dif

f [m

m]

AP1_DZ

AP2_DZ

AC #6GEO #13

AC #4GEO #13

AC #6GEO #3

AC #3GEO #3

Statistics of difference GEO-AC, zoom and details


SSS 49 and 349

Diff GEO –AC as measured

AP1_DX

AP1_DZ AP2_DX AP2_DZ

SSS49 -0.06 -0.250.05/0.2

0 -0.34/-0.23

SSS349 -0.04 -0.24

0.20/0.02 -0.23

Diff GEO –AC corrected using best estimates of calibrations

AP1_DX

AP1_DZ AP2_DX AP2_DZ

SSS49 -0.06 -0.040.05/0.2

0 -0.13/-0.04

SSS349 -0.04 -0.03

0.20/0.02 -0.05

After correction by Patrick


Recent measurements, not corrected

mole 13

-0.008 -0.20 0.026 -0.20

mole 13/4

-0.0029 -0.22 0.02 -0.20

mole 13/6

-0.025 -0.16 0.04 -0.18

24505-Sep-

2005

34306-Oct-

2005

28410-Oct-

2005

16719-Oct-

2005

18020-Oct-

2005

24924-Oct-

2005

16025-Oct-

2005

16326-Oct-

2005

34927-Oct-

2005

4901-Nov-

2005

15003-Nov-

2005

16207-Nov-

2005

22108-Nov-

2005

13 4

13 4

13 4

13 4

13 4

13 4

13 4

13 4

13 4

13 4

13 6

13 6

13 6

H V H V

Difference of AC and GEO: mean for mole combination


Conclusions for the batch

Estimated accuracy 0.2 mm.

For the batch from MEB 102:

For magnet 49, 349: use existing AC mole data with the calibration of offset of -0.09 mm.

Magnet 152, 177 and 249 will be re-measured, no AC mole data available for 152 and 177, 249 will be re-checked and scanned at the ends, to see which mole is closest to flange. Only one magnet has to be remeasured, conclusion drawned and decision taken if we have to remeasure the others


Suggestions for calibrations and checksThe calibrations and maintenance of the moles have to be followed up for all moles used, for all magnets, also in industry

To keep an overall track of this in the data base is offered

We have to estimate how the offsets in calibration and saw tooth influence the statistics for correctors, due to shift in GA and also classification at WP08 (dipole).

Development of a “derived data” package for SSS as for the dipole will be made to estimate important quality criteria.

Magnetic mole calibrations to be revisited as well

Check impact of flange positions for SSS


Installation info (I)1. There are no predefined install packs in the data base for the SSS.

The slot showing the choice for GA calculation is used as install pack. No other install pack is possible unless a new reference measurement is chosen and a new GA is calculated for all valid measurements. This must remain an exception since the reference measurement is chosen by measurement specialists.

2. If several measurements from the same measurement device are available in the database (re-measurements), only one is valid. The others are not accessible (only specialists can access).

3. We will add a slot “install pack” for the SSS. When this slot is filled it will be checked that the install pack chosen by ABP is the same as the measurement used for GA calculation. If this is not the case the filling of shifts and install pack will not be possible. This is to check that no ambiguity exists for validating the shift.


Installation info (II)

1. A list of installation data from the installation data base ( views asked from EDMS team) and the MAS data base will be produced to show slots and magnets with the shift data and fiducials will be produced (web based).

2. For the Dipole, the default for install pack (last measurement) that was implemented according to demands by AB/ABP, will be obsolete.

3. Only one set of fiducial data available for a valid measurement set (mag, mech, fid, SSW)

4. Only once all calculations are made and all measurements are expressed in the same reference system, the certification can be made by looking at all measurements together (MAS).

5. We can add both measurements, AC and GEO, in the shift tool if wanted.


Installation info overview web page

AC/GEO mole measurements Based on outcome from meeting 24/11 2005 and Installation data

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