ALIGNMENT DESIGN AND STATUS OF TAIWAN PHOTON SOURCE WEI-YANG LAI October,

Introduction Taiwan Photon Source (TPS) is a new 3-GeV synchrotron ring with circumference m and 24 double-bend cells Due to the stability consideration, the entire building is constructed half underground at depth 12 m relative to Taiwan Light Source (TLS) For the stability of ground, the building is established on the concrete floor with more than 1m in depth. For the requirement of construction, the concrete floor is constructed 6 times until it is done. The last one area was constructed on June

GPS fiducial points Before the construction, there are only 4 fiducial points of GPS on the roof of buildings. After the TPS started to be constructed, the 4 fiducial points were shifted due to the slight tilt of building For this reason; we increase 4 new fiducial points The 4 new fiducial points were inlaid in the laccoliths, and the inserted depth is up to 5m. Considering the variation of outdoor temperature, the fiducial points of GPS are made by granite to reduce the effect of thermal expansion. After one and half year of construction, the fiducial points of GPS seem to be stable within 2mm Variation of the GPS fiducial points 3

Survey network of GPS In the beginning of the construction, we installed 36 granite pillars as the initial survey network of the TPS. The 36 granite pillars include 12 pillars in the storage ring and 24 pillars in the experiment area. These granite pillars need to be surveyed by GPS system before the roof of the building has started to be constructed. The granite pillars and the GPS fiducial points were surveyed together by the GPS, and the accuracy of that is less than 1mm 4

The initial survey control network When the roof of TPS building has completed, the survey through GPS is not available. Therefore, several windows installed on the inner wall of TPS are available for surveying. We can then obtain the initial survey control network by integrating the survey data obtained from the GPS and the out door laser tracker. A initial survey control network is used for the fundamental construction. (construction of building,the shielding wall, pipe tray) 5

The survey control network of TPS There are two survey holes on each shielding wall, and the survey targets are installed on the two side of the wall, so that the storage ring and the experiment area could be merged by this survey targets. The windows installed on the inner wall can provide the chord length to correct the error propagation from the restricted geometry of the TPS ring the TPS network in the altitude direction is corrected by using precise levelling instrument (DNA03) The difference between twice survey network is 0.5mm(±0.5mm)(two week) 6

Installation of TPS The cement ceiling were removed and been placed on the experiment area from October 2013 to May 2014 because of the requirement of installation and repair of the cement ceiling. We cant merge the experiment and storage ring area through the survey holes on the shielding wall. The difference between twice survey network is 1mm(±1mm)(two week) if the area of survey network only contain the storage ring. frame 7

Variation of TPS in radial direction The number 6 area is the last one area constructed on June 2012,and we record the survey data from July 2012 until now. According to these data base, the thermal expansion of TPS should be about 0.3mm per ℃ We aligned components by these survey control network, and we also consider the temperature of the control network to align the components. After the air condition is operated and let temperature be 25 ℃, the variation of the building affected by temperature seems smaller than before The adjustment girders is still within 1mm on May

Alignment in TPS There are three laser trackers in NSRRC.(Leica AT901,FARO Xi, Leica AT401) We align a lot of components within 0.1~0.2 mm according to the survey control network (girders,pedestals, vacuum chamber,FE element, magnets, BPM, supports ) 9

Alignment of screws and screw holes All the screw holes and screws of the storage ring need to be set up by the survey control network First, We set out an ink line with marks by a laser tracker The contractor drilled the hole roughly according to this marks Glue was injected into holes for bonding the screws on the ground and screw holes on the wall We design templates to align screws and screw holes after the glue being injected, and we could position the screws and screw holes by using a laser tracker After the glue is dry and solidified, the accurately of them are within 2mm. 10

Installation of TPS After the screws and screw holes are completed, we install pedestals by using electric lift craft We align all pedestals by using laser trackers We inject the cement into pedestals After the cement being solid, we can install the girders with the magnets Finally, we can adjust the girder system by the auto-alignment system 11

Auto-alignment process of TPS The new position of each fiducial point of girders is computed from the positions of two near points and the relative position between two points from touch sensor modulus and PSD system. The new coordinates are established under a condition that the sensor accuracy is better than laser tracker, so the accuracy of new coordinates can be improved. We obtained the Initial coordinates by using a laser tracker Obtain the relative position and angle between girders from sensors (PSD, touch sensor modulus) Compute the new coordinates and adjustment of girders Are the transverse and rotation less than 10um 2.5urad Adjust girders by tuning cam movers Get the movement of girders from touch sensors Get the coordinates of girders after tuning movers Recorder all data of sensors Finish auto-alignment process yes no 12

Construction of one cell in TPS There are 16 touch sensor in a cell, and among of that 5 touch sensors are set on a touch sensors modulus, and 3 touch sensors are installed in the end of section. The position of girders can be recorded by theses touch sensors. There is a tilting sensor on each girder, and we use the Nivel220 to record the direction of pitch and roll. Between the straight-section girders, the relative position could be recorded by a laser-PSD. Heidenhain rotary encoder ECN425 Heidenhain length gauge ST1208 Leica Nevil220 tilting sensor Touch sensors modulus 13

Construction of girder system There are 3 pedestals, 6 cam mover, 6 locking system, 12 damper for a girder The locking system could increase the nature frequency. The damper could reduce the amplifier The ratio of gear reducer : 160:1 Cam shaft offset : 7mm The adjusting range is about 4.5mm The torque of motors is 4 N-m, and the adjusting system can sustain the object upto 20 ton. 14

Testing result of girder system The 1 st NF can be raised to 33 with locking mechanisms The Peak amplitude is reduced with dampers All magnet assembling reference channels are measured : around 8~12um Coordinate measuring machine 15

The PSD system of TPS Girder2Girder1 Laser PSD1& Beam Splitter PSD2& Beam Splitter PSD3&Beam Splitter PSD4 Isolation tube(7m&12m) In the transport and installation of girders (from assembling Lab into the storage ring of TPS), most of the PSD modulus are shifted. So, we use relative position from a laser tracker to replace them at present The relative position between two girders in a straight-section could be established by PSD system. The resolution of Photon sensitive device (PSD) is 0.5 um The drift of laser could be corrected by the equation below PSD3=PSD1+L2*tan(θ) PSD4=PSD1+L3*tan(θ) θ=tan -1 [(PSD2-PSD1)/ L1] L1: distance between PSD1 and PSD2, L2: distance between PSD1 and PSD3, L3: distance between PSD1 and PSD4 We can adjust the class window, and let the laser light in the origin path. 16

Length measurement of TPS Some of the difference of angle(θ 3 - θ 1 - θ 2 ) are still around 100 urad We correct the length to meet the condition The correction of value is around 10~20um θ1θ1 θ2θ2 θ3θ3 The relative position between two near girders could be established by touch sensor modulus it was constructed by the length and angles. The length of girders are measured by laser interference, and the length between two near girders are measured by length gauge. Some of them are also shifted in the transport and installation of girders, and we have re-measured the length 17 (X,Y) L

Error equation If the error of length is 20 um Eth3=71urad Eth2=76urad Eth1=35urad Error=116urad 18

Summary Before the air condition is operated, the thermal expansion ratio of TPS is about 0.3mm per ℃ The auto-alignment system is operated smoothly,and the time of adjustment is half hour per round (adjustment is 1mm) The PSD system in a straight-section needs to be measured again. The accuracy of length of touch sensors modulus seems to be 20 um, and it needs to be confirmed and improved. 19

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