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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 2
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 3
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 4
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.
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 5
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 6
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 7
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 8
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 9
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 10
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 11
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 12
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 13
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
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 14
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.
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 15
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.
Measurements and DB meeting 1 December, 2005, Elena Wildner AT/MAS 16
Installation info overview web page