1 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. September,2010 IWAA2010 2

 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 September,2010 IWAA2010 3

September,2010 IWAA 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 Y X Y X 230 meters BEPC layout September,2010 IWAA2010 5

 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. September,2010 IWAA2010 6

September,2010 IWAA Data in 2001 Amount of height difference compared is 38

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. means the height difference of Point R1 and R2 in laser tracker. means the height difference of Point R1 and R2 in level. means the comparing error of the height difference between two instruments. — We calculated the comparing error of height difference according to the two sets of height differences.. September,2010 IWAA2010 8

 Results of the statistic comparing error: M 0 =0.089mm Fig. result of 2001 year The statistic comparing error of height difference: M 0 =0.089 September,2010 IWAA2010 9

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. September,2010 IWAA

September,2010 IWAA Segment Data in 2002 Amount of comparing height difference compared is 57

 Results of the statistic comparing error: Fig. result of 2002 year The statistic error of height difference: M0=0.097mm September,2010 IWAA2010

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 tracker BEPCII LINAC The comparing measurement experiment was completed during the period of BEPC LINAC upgraded to BEPCII LINAC September,2010 IWAA

26 monuments fixed on the wall from LH2 to LH58 at a height of 1.8 meters above the 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. September,2010 IWAA

 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 September,2010 IWAA Three sections backward Three sections forward

September,2010 IWAA Segment data in 2004 Amount of comparing height difference compared is 260

Fig. result in 2004 The statistic comparing error of height difference M 0 :  Results M 0 =0.096mm M 0 =0.096 September,2010 IWAA2010

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 m.  Their circumference is 237 m. September,2010 IWAA

— 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 September,2010 IWAA

September,2010 IWAA Segment data in 2006 Amount of height difference compared is 176

 Results M 0 =0.067mm Fig. result of 2006 year The statistic comparing error of height difference: M 0 =0.067 September,2010 IWAA2010

September,2010 IWAA yearM mm mm mm mm 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. September,2010 IWAA

Fig. result for 4 years The statistic difference of height difference:  Results M 0 =0.087mm M 0 =0.087 September,2010 IWAA2010

September,2010 IWAA Conclusion  Compare error of height difference between laser tracker 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.

September,2010 IWAA Thank you for attention! Men Lingling

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September,2010 IWAA 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.

September,2010 IWAA Closed error in 2002 Closed error MH:

September,2010 IWAA Closed error MH in 2006 Laser tracker : MH=0.4mm Level : MH=0.25mm It was not the closed measurement using laser tracker in 2001 and in Closed error of round trip measurement using level was controlled on a range of 0.3mm in every year.