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Institute of High Energy Physics
13/09/2010
Comparison and Study in Measurement Accuracy of Height Difference
between Laser Tracker and Level Men LingLing Dong Lan Li bo Wang Xiaolong
Introduction As we know, in accelerator alignment field ,we can
get a high accuracy vertical network by level. In this meeting, I want to report a conclusion that we can also get a high accuracy vertical network by
Laser tracker. How is the accuracy of vertical coordinates by laser tracker measuring in single station? From 2001 to 2006,we had ever completed the 4
comparing measurements in height difference between laser tracker and level at BEPCII tunnel. Through analyzing data, we obtain the above result.
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The instrument : FARO Laser Tracker Measuring process: —Adjusting the tracker to level roughly . —Let the tracker to measure the levelness of the instrument finally. —Measuring the 3 dimensional coordinates of control points using the laser tracker in single station. —We construct the level coordinate system by the levelness measured from the tracker in the Insight software. —Extracting the vertical coordinates of control points to calculate the height difference between two points.
The measuring method of height difference using Laser Tracker
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Introduction the comparing measurement and Analysis Result In 2001
Introduction the comparing measurement and Analysis Result In 2002
Introduction the comparing measurement and Analysis Result In 2004
Introduction the comparing measurement and Analysis Result In 2006
Conclusion
Contents
1. The comparing measurement and Analysis Result
In 2001
The measurement Instruments: SMX4500 Laser Tracker and N3 Optical Level Measuring site: The tunnel of BEPC storage ring and LINAC
LINAC
Transport Line
Storage Ring
YX
YX
230 meters
BEPC layout
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Measuring process: — One group measured the height difference between
two adjacent points from R1 to R29 in storage ring tunnel and from G02W2 to G43W2 in LINAC tunnel
with laser tracker.
— Another group measured the height difference between two adjacent points from R1 to R2 in storage ring tunnel and from G02W2 to G43W2 in LINAC
tunnel with level.
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Calculating method
— We calculated two height differences of the same two points according to the two sets of data from Laser Tracker and N3 Level separately .
R2-R1.LR2-R1.TR2-1R HHH ΔΔδ
means the height difference of Point R1 and R2 in laser tracker.
R2-T.R1HΔ
means the height difference of Point R1 and R2 in level.
R2-L.R1HΔ
means the comparing error of the height difference between two instruments .
R2-R1Hδ
— We calculated the comparing error of height difference according to the two sets of height differences.
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Results of the statistic comparing error: M0=0.089mm
differenceheight comparing theofamount
error) comparing the(M
2
0
Fig. result of 2001 year
The statistic comparing error of height difference:
M0=0.089
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2. The comparing measurement and Analysis Result
In 2002 The measurement Instruments: FARO Laser Tracker and NA2 Optical Level
Measuring site: Leveling network of BEPC storage ring
Measuring process:
— One group measured the height difference between two
adjacent points from R1 to R29 and from R1W2 to
R29W2 in storage ring tunnel with laser tracker .
— Another group measured the height difference between two
adjacent points from R1 to R29 and from R1W2 to
R29W2 in storage ring tunnel with level.
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Segment Data in 2002
Amount of comparing height
difference compared is 57
Results of the statistic comparing error:
differenceheight comparing theofamount
error) comparing the(M
2
0
Fig. result of 2002 year
The statistic error of height difference:
M0=0.097mm
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3. The comparing measurement and analysis result In 2004
The measurement instruments: FARO Laser Tracker and NA2 Optical Level Measuring site: Leveling network of BEPCII LINAC
Laser trackerBEPCII LINAC
The comparing measurement experiment was completed during the period of BEPC LINAC upgraded to BEPCII LINAC
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26 monuments fixed on the wall from LH2 to LH58 at a height of 1.8 meters abovethe floor spaced at intervals of 8 meters
control monuments distributing of BEPCII LINAC
24 monuments on floor along the LINAC girder between L101 and L102 spaced at intervals of 8 meters over 230 meters.
26 monuments fixed on floor along the foot of the wall from L2 to L58 at intervals of 8 meters.
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The Laser tracker measured three sections forward and three backward in each station, and 20 monuments can be measured.
Floor monument
Tracker
The tracker was measuring the floor monument
NA2 level
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Three sections backward
Three sections forward
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Segment data in 2004
Amount of comparing height
difference compared is 260
Fig. result in 2004
The statistic comparing error of height difference M0:
differenceheight comparing ofamount
error) comparing the(M
2
0
Results M0=0.096mm M0=0.096
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4. The comparing measurement and analysis result in 2006
The measurement Instruments: FARO Laser Tracker and NA2 Optical Level
Measuring site: Leveling network of BEPCII storage ring
— Brief introduction of BEPCII storage ring
It consists of both the positron and the electron rings.
The distance between the beam centerlines of the two rings is 1.179 m.
Their circumference is 237 m.
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— control monuments distributing of BEPCII Storage Ring
The 3 dimensional tunnel network consist of 201 control points. The 3 dimensional monuments were fixed on the floor and wall of the storage ring tunnel.
67 monuments on the wall about 1.8m high
67 monuments along the foot of the wall
67 monuments on floor along the girder spaced at intervals of 6 meters over 237 meters.
BEPCII layout
19
Leveling staff
Optical tooling scale fixed on the tooling ball
1.5inches tooling ball
Wall monument
NA2 level
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Results M0=0.067mm
Fig. result of 2006 year
The statistic comparing error of height difference:
M0=0.067differenceheight comparing ofamount
error) comparing the(M
2
0
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year M0
2001 0.089mm
2002 0.097mm
2004 0.096mm
2006 0.067mm
Tab. Statistic comparing error M0 of height difference
between laser tracker and level in 4 years
Results of 4 years
Amount of height difference compared is 531
We calculate the statistic error of height difference to all data of 4 years together.
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Fig. result for 4 years
The statistic difference of height difference:
Results M0=0.087mmM0=0.087
differenceheight comparing ofamount
error) comparing the(M
2
0
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Conclusion Compare error of height difference between laser track
er in single station and level is 0.087mm. In the accelerator vertical measurement ,laser tracker can
instead of level certainly. From 2007 to 2010,we use laser tracker to measure the
tunnel vertical network of BEPCII instead of level throughly. The result of measurement can meet the requirement of accelerator run. The BEPCII alignment is brought about the 3 dimensional measurement in
single laser tracker only.
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abstract
On the basis of data which we measured in the last few years in BEPCII tunnel, we compare and study in measurement accuracy of height difference between laser tracker and level. Compare error of laser tracker in single station and level is 0.087mm. The results show that the accuracy of laser tracker measuring vertical network in single station meets the requirement of accelerator physics. the accelerator vertical measurement ,laser tracker can instead of level certainly.