Transcript BEPCII Prealignment Installation Survey and Alignment Accelerator Center of IHEP Xiaolong Wang

BEPCII Prealignment Installation
Survey and Alignment
Accelerator Center of IHEP
Xiaolong Wang
2007.5.3
Brief introduction of BEPCII Alignment
• BEPCII alignment can be divided into three parts,
calibration magnets, prealignment installation
and tunnel survey and alignment.
• As BEPCII is constructed in the existing BEPC
tunnel, the space for survey and installation is
very narrow. So we arranged calibration
magnets and prealignment installation in a hall
outside of the tunnel.
• There are 84 cells need to do prealignment
installation ,and it was started on August 2005
and finished on August 2006.
BEPCII Prealignment Installation
introduction
• We arranged two groups to do magnets
calibration and prealignment installation together.
Each group includes two alignment technicians
and two workers. Beside these, a lift worker
worked for these two groups.
• Measurement devices are laser tracker, leica
NA2 and electronic gradienter.
• The components need to install in a cell
generally are dipole, quadruple, sextuple, BV
magnet, vacuum system, girder and so on.
• Each time can install two cells and finished in 45 days.
BEPCII Prealignment Installation
introduction
• According to the sequence of the prealignment,
it includes calibration magnets, install magnets
on the girder, roughly adjust the magnets, install
vacuum system, precisely adjust the magnets
and the vacuum chamber, fix the magnets and
the vacuum system to the girder, lifting and
transport the cell to the tunnel.
• We use laser tracker to do magnets calibration.
Through measuring the fiducial planes and the
fiducal points on the magnet, we can construct a
frame for the magnet, in this frame we can get
the coordinates of the fiducal points.
BEPCII Prealignment Installation
introduction
Calibration dipole
Prealignment cell
Calibration sextuple
BEPCII Prealignment Installation
introduction
• Accelerator physics requires dipole’s Roll
tolerance should be 0.1mrad, it’s can not be
realized only with laser tracker. We use leica
NA2 and electronic gradienter to do the Roll
Electronic
calibration.
gradienter
Leica NA2
Target
Fiducial
plane
Adjust the lower pole to level
Measure dipole’s Roll
BEPCII Prealignment Installation
introduction
• After get the calibration coordinates of the magnets that
are installed in one cell, we should calculate the nominal
coordinates of these magnets. For each cell, we
constructed a frame. The frame’s origin is on the center
of the dipole, z points to the beam direction, y vertically
points to the up, right hand coordinate system. According
to the parameters given by accelerator physics we can
convert these calibration coordinates to the nominal
coordinates in the cell frame.
• After get the nominal coordinates, we input them into the
laser tracker and then survey and adjust the magnets to
the required installation precision.
BEPCII Prealignment Installation
introduction
• We found temperature change can markedly
influence the precision of the magnets’ position.
It’s necessary to do some correction to the
nominal coordinates.
• Through longtime experiment, we got an
appropriate correctional coefficient, each time
before adjustment, we use this coefficient
multiply the nominal coordinates to do the
correction.
BEPCII Prealignment Installation
introduction
• Requirement of magnets calibration and
prealignment installation precision.
X
Y
Z
(mm) (mm) (mm)
dipole
0.1
0.1
X (mm)
Y (mm)
Z (mm)
quadruple
0.050.08
0.050.08
0.08
sextuple
0.050.08
0.050.08
0.08
0.15
quadruple
0.04
0.04
0.1
sextuple
0.05
0.05
0.1
BV
magnet
0.15
0.15
0.15
BV
magnet
0.15
0.15
0.15
vacuum
chamber
0.5
0.3
0.5
magnets calibration precision
prealignment installation precision
BEPCII storage rings alignment
introduction
Storage Ring
240
meters
long
eijing
ynchrotron
adiation
acility
Beijing
Spectrometer
LINAC,
202 meters
long
Two transport lines,
total 160 meters
long
Beijing
Synchrotro
Radiation Facility
BEPCII storage rings alignment
introduction
• The BEPCII Surface Network consists of 4
permanent monuments named T65P, T65E,
L101 and L102. We use T65P and T65E to
control the storage ring position, use the L101
and L102 to control the LINAC position.
Storage
Ring
Transport Line
LINAC
230 meters
Two
permanent
points to
control ring
Y
Y
XX
Two permanent points
to control LINAC
BEPCII storage rings alignment
introduction
• LINAC alignment was finished in 2005, here only
introduce the storage rings’ installation and
alignment.
• We layout a three dimensional control network in
storage rings tunnel, measure its horizontal
coordinate with total station and laser tracker,
measure its vertical coordinate with level, and
then we measure and adjust the components’
position with laser tracker relative to the three
dimension network.
The Alignment Tolerance(rms)
• The global point error of horizontal network is 0.82mm
• The relative point error of horizontal network between
two adjacent control point is 0.08mm.
• The global point error of vertical network is 0.33mm
• The relative point error of vertical network between two
adjacent control point is 0.06mm.
• The global position accuracy of equipment in horizontal
is 0.82mm and vertical is 0.33mm.
• The relative position accuracy of equipments in
horizontal and vertical is 0.15mm
BEPCII storage rings alignment
introduction
• The surface network in
horizontal consist of 37
main control points.
• In collision area (from
R25 to R30) and aisle
area (R37,R1,R17,R18 ),
we have to measure
between long distance
and the interference to
measurement is great, so
we use total station
TDA5005 to measure the
surface network. It needs
about 5 days.
The surface network of the BEPCII
storage rings
BEPCII storage rings alignment
introduction
We use the total station of Leica TDM5005 to survey the surface
network in horizontal in forced centering mode on the ground.
• The total station was
centered on the point to
measure the directions
and distances of other
points like the figure. The
triangulation
measurement accuracy
of the total station is 2.2
seconds. The distance
measurement accuracy
of the total station is
0.17mm.
Surveyor
Total
Station
BEPCII storage rings alignment
introduction
• In the arc area, we have
good measurement
environment, so use
laser tracker to measure
the surface network can
be efficiently.
• The floor and wall of
storage rings tunnel
was populated with
3 dimensional
monuments
Laser tracker .
monuments on
the wall .about
1.8m high
monuments on floor
monuments on floor
along the girder .
along the foot of the wall
intervals are about 3.5m
.
The Cut View of Tunnel
BEPCII storage rings alignment
introduction
• Each station, laser
tracker measures
two front sections
and three back
sections. In one
station 20
monuments can be
measured.
• It needs about 1012 days to finish the
network survey by
laser tracker.
Laser tracker station
monuments
Laser tracker surveys tunnel network
BEPCII storage rings alignment
introduction
• We use the Leica
NA2 level to measure
the vertical coordinate
of the tunnel network.
• The level is setup
along tunnel at
intervals of 7 meters
to measure the height
of every monument in
direct and reversed
observation mode.
Optical tooling scale for
measuring height of wall
monument
The leveling staff for
measuring the height
of floor monument
BEPCII storage rings alignment
introduction
• The closing error of height in direct and reversed
observation should be less than 0.1mm.
• Using “shanwei” software to do the vertical
coordinate adjustment.
• The maximum absolute vertical coordinate error
should be 0.33mm(rms). The maximum relative
vertical coordinate error between adjacent
control points should be 0.06mm.
BEPCII storage rings alignment
introduction
 The construction of 3 dimensional nominal
coordinate of the tunnel network .
• The three dimensional coordinate of the network
consists of horizontal coordinate and vertical
coordinate.
• The horizontal coordinate stems from a
measurement to the network in horizontal with
total station and tracker.
• The vertical coordinate stems from a
measurement to the network in vertical with level.
BEPCII storage rings alignment
introduction
• For the installation and alignment of the storage
ring, we use laser tracker to align the
components with respect to the 3D tunnel
control network, and also improve the alignment
accuracy with level and electronic gradienter .
• Before adjust a cell, we first check the position
correlation of the magnets on the girder. If their
correlation occurs to change and don’t satisfied
with the requirement, we will readjust them.
BEPCII storage rings alignment
introduction
• When adjusting the position of a component, we first use
the laser tracker to measure monuments populated in 3
dimensions adjacent to the component, and best-fit the
actual coordinates of these monuments to their nominal
coordinates of the network, the standard deviation of the
best-fit should be less than 0.07mm. After the best-fit of
coordinates, the difference between nominal position
and actual position of the component can be displayed
by laser tracker.
• Adjust the component until the offsets within required
installation precision.
• We measured the tunnel network and components again
after all components of BEPCII storage rings had been
wholly installed, then smoothed all the components.
BEPCII storage rings alignment
introduction
Storage rings alignment schedule.
 Jul. 2005 - Aug. 2005 Survey the tunnel
network.
 Sep.2005 – Oct.2005 Mark beam lines on
the tunnel floor.
 Mar.2006 – Sep.2006 Storage rings tunnel
installation and alignment.
 Oct.2006 – Nov.2006 The adjustment to
smooth all the components.
BEPCII storage rings alignment
introduction
• Tolerable displacements for storage ring magnets
(components) defined by the accelerator physics
The circumference of storage rings cannot deviate from its design value
by more than 5mm; the difference between two rings has to be set within 4mm.
Summary
• According to the component installation
tolerance of the BEPCII storage rings which
accelerator physics gives, the scheme of every
taches had been carefully studied and the total
tolerance was reasonably distributed to the
taches in course of the component installation.
So the total tolerance of the component
installation is successfully limited in the range of
physics requirement.
Thanks for your
attentions !