The properties of very thin silica fibers for use in precision
Contents
1. 2 Riesgos Pos Move Acceleration mme fp os TL Jog Direction Set Max Jog Time ms Newport Current Pos Move Velocity mm s Pick Motor Movement ANewport Current Pos Move Acceleration mmve r Check Move Param Match Check Jog File Fo Check File Disabled Set Newport Move Parameters i Reinit To Default Pick Motor Movement e Visible i Newport Current Pos Move Acceleration mm s 1 Pocatiei Set TL Move Parameters BL Curent Mii mmi y Set TL Move Parameters Reinit To Default Pulling Dataset tt file Pre prem Piisible D PBlinking gt Reinitialize these parameters to default each time the VI is called Pdicabled J so that the user must set the velocities and accelerations Delay Pull After Laser ance Past End Pos gt leach time the stages are connected otherwise the parameters will return to the default values 4 p Disabled o pvisible n i Current State Delay Start Pull Time ms AT Cren Immo Blinking After Laser o E PpDisabled EH t Preis TL Jog Direction Delay TL Start ms Check Jog File Disabled After Newport L Pig hanges limits on relative position moves so that they update depending on the current position Set Newport Move Parameters Pick Motor Movement r l Pvisibie LE Delay TL Stop md Sa a Enter New Parameters Newport Relative Displacement mm Set TL Move Parameters Disabled After Laser wong e Bose T Pulling2. author additional information on the program is provided in section V Clamps will be 11 University of Glasgow IREU 2014 Alyssa Conway mounted on each stage attaching one end of the silica fiber to each stage while the conical mirrors remain stationary Newport 400 mm stage ThorLabs 50 mm stage Clamps for ends of silica fiber Gold conical mirror Figure 8 CAD rendering of micro fiber pulling machine courtesy of Dr Liam Cunningham and Russell Jones The speed of the pull with this setup will be much greater than that of the previous fiber puller and the starting silica stock will be smaller to produce even thinner shorter fibers As a result moving the mirrors to redirect the beam along different positions on the silica stock may not be necessary hence the conical mirrors are currently drawn as stationary in the most recent diagrams Figures 9 and 10 In addition contrary to initial 12 University of Glasgow IREU 2014 Alyssa Conway plans the Newport stage must be mounted horizontally according to the manufacturer Consequently a new model of the machine was created that is essentially the previous model rotated on its side so that the Newport stage can run horizontally all of the diagrams Figures 8 9 and 10 included here are from the most recent as of August 2014 CAD renderings from Dr Liam Cunningham Again because the pull will be fairly quick concerns over gravity s influence causing any d
3. up positive with accelerations from 0 0001 mm s to 4 500 mm s All subVis for the Newport upper stage are BLUE All subVls for the ThorLabs lower stage are PURPLI die Default 7 Newport Current Position mm WAIT Stages BI Homin MG17Motor Homing 5 D EEE e pBlinking ica Ps END VI SAFELY go MGI7Motor True 7 D E Stages WAIT 5 GIT Motor Hein t MGI7Motor Visible Stepctd Move loniae a HA TL Current Position mm T WAIT eset Newport Pos Move Params Hy Stac v 5 ye ges WAIT E 2 Homing Stages idle XE Homing Current State Set TL m GIAA Reinit To Default 2 pBlinking E TL Current MinVel mm s Both Newport amp Thorlabs Default 7 Reinit To Default WAIT Stages Homino 7 jog tir indi TL Current MaxVel mm s d ri parameters match the actually maxjog time control and indicator Advance Past End Pos Fo Move Relative Postion a Frere eee depending on whether checking the input file Ge pe LS YER D Set Newport Move Parameters Max Jog Time ms TL Current Acceleration mm s gt Em m x Stop Pull
4. A AA A A N SA SA SA SA SA SA SASA SA SA kk SASA SA SA SA Sk SA SN SA G SA SA SA A SA S SA OA SA S SA A SSR Sa SA SA Sk SASA SA CH SA SA SA SA SASA SA SA SASA S SASA SA A SA SA OA SASA SA Sd CA SA ak A SA SA Sk SA SA SA SASA SA SA SA SA GA SASA Sk SASA OA SA SA SA SASA SA A Saad A 2 Move by position states A 2 1 Absolute Position State Alyssa Conway Sa SSS SS SaaS SS SSS SSS Sa SSS aS SS Sa aS Hides Check File control and max time indicator only allowing user to manually enter max jog Max Jog Time ms mum bvisitie HL ka Visible Set Max Jog Time ms MMNCNCSDODODOODOOOSOSOOOOOOOOOOOOOOO2OOOOOOOOOOODOOOOOODOOOOOOOOOOOOOOOOOOQOOSOSDOSOODOOOSOOCE RAA N A OE S SA A SRSA SA SA OA SA SA SASA SA SA SASA SA CA SA SA SA GA SA SA SA SA SA SA SA SA SA SA SA SASA SA SA OA SASA SA SASA SA CA SA SA A SA SA SA A SA SA SA SA SA SASA SASA SA SA SA SA SA A SA SA A SASA SA A SA SA AS 34 University of Glasgow IREU 2014 Alyssa Conway SRE 7 Move Absolute Position anniek TL Target Absolute Position mm seti Current State 7t lt 2 ug linking A 2 2 Move Relative Position State 35 University of Glasgow IREU 2014 Alyssa Conway ET z Move Relative Position aaa A 3 Set movement parameters states A 3 Set Newport Position Movement Parameters State 36 University of Glasgow IREU 2014 Set Newport parameters for moving to absolute
5. Controls Delay Bull After Laser Delay TL Start ms Delay After Newport AS gi 00001 j 0 0001 TL Stop ms fter t Max Jog Time ms 14150 1 Pulling Dataset txt file lm Fibre Puller Dual Motor a velocities tryl da Pick Motor Movement A 4 Both Newport amp Thorlabs Current State Idie Enter a tet file with three columns 1st Velocity mm s 2nd Acceleration mm s 3rd Time ms Text files should have ONLY NUMBERS and he tah delimited copy amp paste from excel works finc For corresponding rows indices the Newport stage will move at the constent velocity for the corresponding time and will accelerate from the previous velocity to reach the new velocity using the corresponding acceleration Monitor Jog Indicators Newport Current Position mm 0 0000 TL Current Position mm 0 0002623E Time Jogging ms Index 14088 8 Jog Ending Position mm Total Jog Displacement mm 383461 381461 Arcelerahon mm Calculated TL Calculated TL Jo fum Jog Ending Position mm Total Jog Displacement mm Time ms 163798 16 9801 Jog File Info Velocity mm s Calculated Newport Calculated Newport j 0 fn j po Figure 16 Front panel of micro fiber dual motor control program A File entry The VI prompts the user for a pulling file which should include the velocity acceleration and time parameters to control the movemen
6. Dataset ot file A Newport Current Position mm Newport Relative Displacement mm Disabled Disabled Start Pull prem i E Beg Minimum Advance Past End Pos Delay Pull After Laser Pose Porsbied Hides and disables all controls while the stages are connecting and moving to home positions Reset Start Pos Delay Start Pull Time ms After Laser tft CheckJogFile D Delay TL Start ms Visible TL Relative Displacement mm pr s e Enabled gt Disabled Delay TL Stop ms inter New Parameters y di TL Relative Displacement mm After Laser o pisi p gt Pier D Dialed Start Pull d PViible Delay Start Pull Time ms After Laser RDelzy Pull After Laserr pvisibie Laser Ready Open Close Shutter o indicator and Control that ultimately control the timing between when the laser is ready when the shutter opens and when the stages begin to move When adding programmatic control of the laser shutter use these controls indicators A 1 1 Idle State Newport Only University of Glasgow IREU 2014 Alyssa Conway LLL LLL LAL EAL EEE LLL ALLL EE EAE EE EEE ELLE AA LAL EE EEE EEE EE EEE RA SEE ESE SE ESAS SESE SE ESAS SE SESE SASS SE SSS SSS SSS aS a SSS Sa SS aS a a Upper Newport Only Checks whether user set movement parameters match the actually set parameters Shows hides max jog time control and indicator ft New
7. amp Start Jog LN Figure 14 Progression of states in dual motor control program schematic diagram can be chosen for Newport stage only for ThorLabs stage only or for both stages simultaneously once connected 21 University of Glasgow IREU 2014 status Newport IMS 400LM High Performance Long Travel Linear Motor Stage controlled by XPS Q8 Motion Controller IP Address 192 680 254 Group Name Group Positioner Name Group1 Pos travels along positions 200 mm to 200 mm at velocities from 500 mm s to 500 mm s excluding 0 mm s with accelerations from 0 0001 mm to 26 000 mm s ThorLabs MTS50 M Z8 Motorized Translation Stage SN 417192 controlled by ThorLabs TDCO01 APT DC Servo Controller SN 83823439 travels along positions 1 000 mm to 49 000 mm at velocities in range from 0 mm s to 24 mm s in either direction up positive with accelerations from 0 0001 mmn s to 4 500 mm s Newport Current Position mm Idle Default Alyssa Conway END VI SAFELY o status gt WAIT Stges joldle m Homing Current State Set Newport Move Parameters Pick Motor pia Set TL Move Parameters Advance Past End Pos Reset Start Pos Fi x Es WAIT re Stages tages Homing MGL7Motor Homing remm p Bri WAT MGL7Motor met Stages Homing prs ni Move Lower Motor to Z ro uuumuuuugumuoHnuugunuuu TL Jog Direction Disa
8. calculated displacements Thus any additional time if larger than 10s or 100s of milliseconds depending on the speed of the stage should be added into the file check state and subVIs At the moment both stop subVIs are in the same case in the state machine since stopping both stages at the same time or as close to it as possible seems the most likely scenario If larger time delays are necessary creating separate states for each stop subVI with time delays in place somewhere will likely be the easiest route similarly to close the shutter 1n relation to stopping either stage just add time delays at the appropriate places before after the stop subvis If the shutter should be closed before pulling stops just be sure to not include a zero Jog velocity at the end of the pulling file then close the shutter before the stop subvis C Stop errors 27 University of Glasgow IREU 2014 Alyssa Conway Within the Newport Stop Jog Motion amp Disable Jog Mode subvi if an error occurs that causes the Newport movement status to no longer be enabled this will enable jog control stop the motor by setting the jog velocity to be zero and then disable jog mode the VI will return to the Idle state and the stage itself will return to the ready status NB This will cause any errors that occurred before entering the subVI to be reset to OK at the end The loop will end disconnect the stages and end the VI if there is an error However if addit
9. p Maximum TL Relative Displacement mm Laser Ready Open Close Shutter us Indicator and Control that ultimately control the when the laser is ready when the shutter opens and when the stages begin to move When adding programmatic control of the laser shutter use these controls indicators Max Jog Time ms ILE ET Set Max Jog Time ms Set Newport Move Parameters fo Set Newport Pos Move Params y B 5 e STE m Set TL All Move Params X E Advance Past End Pos fe Move Relative Position F Reset Start Pos fo Move Absolute Position F SS Check Move Param Match Check Jog File Check File 3 Current State Ping Stop Pull L TL Jog Direction Disabled Set Newport Move Patameters ILL Pick Motor Movement Disabled Dataset bt file Disable Advance Past End Pos Delay Pull After Laser T Reset Start Pos Delay Start Pull Time ms frand Males CheklogFie E Delay TL Start ms pra After Newport pVisible n 3 e Enabled 1 pOicabled Delay TL Stop ms After Laser Enter New Parameters Disabled Start Pull Delay Start Pull Time ms After Laser toes Pull After Lasen Pull After Laser 4 MG17Motor StopCtrl WAIT Stages Homing Reinit To Default TL Current MinVel mm s TL Current MaxVel mm s Reinit To Default TL Curren
10. Cumming Alan V Aspects of mirrors and suspensions for advanced gravitational wave detectors Thesis University of Glasgow 2008 Cumming A et al Design and development of the Advanced LIGO monolithic fused silica suspension Draft for LSC Review University of Glasgow draft Heptonstall A et al CO laser production of fused silica fibers for use in interferometric gravitational wave detector mirror suspensions Review of Scientific Instruments 82 011301 2011 OFS Optical Fiber Solutions A Furukawa Company Producing Oil and Gas www specialtyPhotonics com Westphal T et al Design of the 10 m AEI prototype facility for interferometry studies Appl Phys B 106 551 557 2012 DOI 10 1007 s00340 012 4878 z XPS Q8 Universal High Performance Motion Controller Driver User s Manual Software Tools and Tutorial V1 2 x Newport Corporations Irvine CA 2012 30 University of Glasgow IREU 2014 Alyssa Conway ACKNOWLEDGEMENTS First I need to thank everyone involved in the IREU and the University of Florida and the NSF who made this possible Dr Bernard Whiting Dr Guido Mueller Dr Michele Heurs Antonis Mytidis and Kristin Nichola For the guidance advice help and for making sure I got to light something on fire and put it out safely thanks to Dr Giles Hammond Dr Alan Cumming Dr Liam Cunningham Russell Jones Sheena Barclay Dr Angus Bell Dr Jamie Scott and Stev
11. Disable Jog Mode subvi vi aam TL Initiate Move Velocity Only subvi vi wel D Short Fibre Puller Dual Motor Controls TL Initiate Move Velocity Only subvi vi Joa Newport Change Jog Parameters subvi vi Param D Short Fibre Puller Dual Motor Controls Newport Change Jog Parameters subvi vi 46 University of Glasgow IREU 2014 Alyssa Conway Initial Newport Enable Jog Mode subvi vi Jog D Short Fibre Puller Dual Motor Controls Newport Enable Jog Mode subvi vi TL runs too far 2 Display Message to User Invalid filepath 2 Display Message to User Newport runs too far 2 Display Message to User Last velocity not zero 2 Display Message to User amp Invalid filepath Display Message to User TL runs too far Display Message to User Check TL Check Vel Acc Time subvi vi m D Short Fibre Puller Dual Motor Controls VTL Check Vel Acc Time subvi vi ma Newport runs too far Display Message to User ma Last velocity not zero Display Message to User Check Dual File Check Vel Acc Time subvi vi DWShortFibre Puller Dual Motor Controls Dual File Check Vel Acc Time subvi vi Time Delay too large Display Message to User ReadFromSpreadsheet File DBL vi E C Program Files National Instruments VyLabVIEW 2013 Nvi libJUtilityMile llb A Read From Spreadsheet File DBL vi S5 Read From Spreadsheet File vi dt C Program Files WNational Instruments y LabVIEW 2013 vi lib Utility file llb Read From Spreadsh
12. I INTRODUCTION Gravitational waves as predicted by Albert Einstein s Theory of General Relativity in 1916 are ripples in the curvature of spacetime Although gravitational waves have been indirectly detected present research focuses on direct detection Sources for direct detection include violent astronomical phenomena binary star systems and black holes Currently ground based interferometry is an important branch in direct detection attempts with great experimental difficulties arising from the small amplitude change to be detected at very low frequencies amongst many noise sources In order to reduce seismic noise and isolate mirrors in interferometers multi staged pendulum suspension systems are used Then thermal noise from the suspension becomes the primary noise source at low 5 50 Hz frequencies as shown in Figure 1 Seismic H 7 Suspension TN Substrate TN Coating TN Tron Thermorefractive Shot 250Hz h f lI Sqrt Hz Frequency Hz Figure 1 GEO600 theoretical noise sources via Cumming Thesis Figure 1 8 pg 25 University of Glasgow IREU 2014 Alyssa Conway As aresult producing low thermal noise suspensions is an important subfield in current gravitational wave research The lowest loss and lowest thermal noise 1s achieved if the entire system is monolithic that is if the system were made out of the same piece of material the suspension
13. TL Poll for Homing Finished subvi vi TL Motor Control Home subvi vi D Short Fibre Puller Dual Motor Controls TL Motor Control Home subvi vi Newport Kill All amp Disconnect subvi vi D Short Fibre Puller Dual Motor Controls Newport Kill All amp Disconnect subvi vi 48 University of Glasgow IREU 2014 Alyssa Conway Cnect IIT amp Home E Newport Connect amp Initialize amp Home subvi vi D Short Fibre Puller Dual Motor Controls V Newport Connect amp Initialize amp Home subvi vi TL Connect Lower Motor subvi vi D Short Fibre Puller Dual Motor Controls VTL Connect Lower Motor subvi vi EnumBothStages ctl D Short Fibre Puller Dual Motor Controls EnumBothStages ctl Velocity or Acceleration out of range Display Message to User Velocity or Acceleration out of range 2 Display Message to User 49
14. Time s Figure 12 SGamma motion profile for maximum velocity 0 8 units s maximum acceleration 12 units s minimum jerk time 0 004 s maximum jerk time 0 04 s A 3 Tuning While operating the stage within its recommended software limits maximum speed with no load 500 mm s maximum acceleration with no load 26 mm s the standard Newport settings for the PID parameters in the stage initialization stage ini files should work adequately If performance optimization 1s still necessary or if following errors are detected the user can automatically or manually tune the PID parameters using LabVIEW or the online XPS interface Instructions for tuning are on pages 177 179 in the XPS User s Manual To access the PID parameters individually through LabVIEW subVIs follow palettes XPS O8 gt 17 University of Glasgow IREU 2014 Alyssa Conway Positioner gt Positioner Corrector PIDFF Acceleration Set Alternatively the stages ini file can be accessed directly through the online XPS interface Once connected online see the Quick Start Guide for connection instructions enter the IP address of the connection presently 792 166 0 254 for the url and enter or select Administrator for the Name Password and Rights fields Select STAGE from the top menu then Modify from the submenu then select JMS400LM XPS DRV0O2 and press Modify Change the necessary parameters press Save and then Reboot after about 20 seconds the XPS driver s
15. University of Glasgow IREU 2014 Alyssa Conway The properties of very thin silica fibers for use in precision measurement experiments Alyssa Conway Department of Physics Lake Forest College 555 N Sheridan Rd Lake Forest IL 60093 USA Summary To directly detect gravitational waves using ground based interferometers enormous experimental efforts to minimize noise are underway Suspension thermal noise the main noise source for low frequencies can be minimized using multi staged pendulum suspension systems of quasi monolithic fused silica Such fibers of 380 to 400 micrometer diameters have been pulled at the University of Glasgow using a 120 W 10 6 micrometer wavelength CO laser fused silica fiber pulling machine and similar fibers have been used in GEO600 and aLIGO Work 1s in the early stages at the University of Glasgow to create a micro fiber puller which would create one to twenty micrometer diameter fused silica fibers with lengths from five to fifty millimeter pulled from one to two millimeter fused silica stock using a similar CO laser setup These ultra thin fibers could be used in small prototypes like the 10 m prototype at AEI to test and minimize shot noise and radiation pressure noise The author wrote the LabVIEW control programs for the motorized stages that will pull the silica in the new machine and machining and assembly of the micro fiber puller are ongoing University of Glasgow IREU 2014 Alyssa Conway
16. achine capable of creating fibers that meet strength thermal noise and dimensional tolerance requirements for aLIGO generation gravitational wave detector mirror suspensions Heptonstall et al The resulting fibers are 380 micrometers in diameter at their thinnest central section Heptonstall et al The machine employs a 120 W CO laser that produces infrared radiation at a wavelength of 10 6 micrometers which 1s directed with a Zinc Selenium telescope two gold coated conical mirrors and a rotating 45 degree gold mirror to focus at a fixed point along the silica fiber A meter tall double leadscrew tower on which two carriages run is mounted vertically Each carriage is driven independently by a DC servo motor that 1s controlled by a LabVIEW control program Cumming Thesis 76 The silica fiber 1s clamped to one fixed end below and to a moving clamp on the upper moving carriage the bottom conical mirror is also fixed while the upper conical mirror is mounted on the lower moving carriage The fiber pulling machine and a close up of the mirrors directing the laser are diagramed in Figures 4 and 5 from the paper by Heptonstall et al a photograph of the original laser setup from the same paper is also included as Figure 6 A University of Glasgow IREU 2014 Alyssa Conway more recent between 2008 and 2014 photograph of the fiber puller at the University of Glasgow is also included in Figures 7 twin ballscrew unit upper mo
17. bled Pick Motor Movement Disabled Pulling Dataset bt file Disabled Delay Pull After Laser UL X t pDisabled t Delay Start Pull Time ms After Laser 7 2 Delay TL Start ms After Newport pres v Enabled PDisabled 4 Delay TL Stop ms Mul Set Max Jog Time ms i Disabled Hides and disables all controls while the stages are connecting and movit Figure 15 Block diagram of micro fiber dual motor control program in its default dle state ito home positio Ed TL Current Position mm Both Newport amp Thorlabs Default v Shows hides max jog time control and indicator whether user set movement parameters match the actually set parameters leen cn whether chekina the ino fie Newport Pos Move Velocity mm s gt ftNewport Current Pos Move Velocity mm s Newport Pos Move Acceleration mm s P ftNewport Current Pos Move Acceleration mm s 1 Set Newport Move Parameters n D ATL Current MinVel mm s de Set TL Move Parameters ATL Min Vel mm s P D rmm 3 pBlinking ATL Current Mavvel mms ATL Max Vel m s ip ATL Current Acceleration mm s gt ATL Acceleration mm s H nges limits on relative moves so that they update depending on the current position Newport Relative Displacement mm Newport Relative Displacement mm El p finm ftNewport Current Position mm M TL Relative Displacement mm
18. d select controls are made visible on the front panel Then the VI runs in a state machine format until the user or an error ends the VI and the stages disconnect More specifically Figure 14 shows the different paths that can be taken in the state machine the user can choose once the stages are connected whether to control only one of the stages or to control both simultaneously In addition Figure 15 shows the block diagram in its default d e state and Figure 16 shows the front panel for user interface Additional screen captures of the other states are included in Appendix A along with a list of all the subVIs necessary for the VI to run Connect amp NEWPORT Disconnect Stages Home Stages State Machine Control Set Movement Parameters Set Position Reinitialize Check Pull File Move by Jog Pull Stop Movement Pick Motor Movement Both Newport only ThorLabs only Laser Control Figure 13 Dual motor control block diagram schematic some controls Edit Visible Controls 20 University of Glasgow IREU 2014 Alyssa Conway Set Position Buttons Disconnect Motors Move by Position amp End Program absolute or relative Set Move Param Buttons Set Movement Parameters Enter New Param Button STOP END Button Connect Initialize Home Zero Motors Check File Button File Error Enter New Check Pull File Parameters or File OKAY Pull Pull Button Wait
19. e Though the END button is still available in case something gets hung up in the loop somehow A 7 2 Pulling State ThorLabs Only 43 University of Glasgow IREU 2014 Alyssa Conway ATL Current Position mm f TL Jog Direction gt A 7 3 Pulling State Default Both Stages 44 University of Glasgow IREU 2014 Alyssa Conway Both Newport amp Thorlabs Default v M ftNewport Current Position mm YJOOOOOOORQOOOOOOOOOODOOOKDOKOOOOOOO00G NENNEN 00000000 ftiime ms gt m iteration Newport error k gr adap mE Index Current Time ms Time Jogging ms Start Time ms ft Max Jog Time ms Stop Pull TL forced to start AFTER Newport and the time delay must be J ITE PPP 5 5 5 zs less than the time Newport moves E 8 lat its first velocity em Dn m a B Delay TL Start ms V After Newport mn 1 Co inst ry po A S Stop State 45 University of Glasgow IREU 2014 Alyssa Conway APPENDIX B CO Laser Pulling Machine LabVIEW Program SubVI List BEP TL Immediate Stop subvi vi Vel D Short Fibre Puller Dual Motor Controls TL Immediate Stop subvi vi stop Newport Stop Jog Motion amp Disable Jog Mode subvi vi J98 _ D Short Fibre Puller Dual Motor Controls Newport Stop Jog Motion amp
20. eet File vi 47 University of Glasgow IREU 2014 Alyssa Conway Valid Path Set Param Move Param Move Param Rel love Rel Abs Move Abs Gat os QW Get os Tow Home Fall HOME Kill amp Disco nnect Dual Check Valid Filepath subvi vi D Short Fibre Puller Dual Motor Controls Dual Check Valid Filepath subvi vi TL Set Velocity amp Accel Parameters subvi vi D Short Fibre Puller Dual Motor Controls TL Set Velocity amp Accel Parameters subvi vi Newport Get Move Parameters subvi vi D Short Fibre Puller Dual Motor Controls Newport Get Move Parameters subvi vi Newport Set Move Parameters subvi vi D Short Fibre Puller Dual Motor Controls Newport Set Move Parameters subvi vi Newport Move Relative subvi vi D Short Fibre Puller Dual Motor Controls Newport Move Relative subvi vi TL Move Relative Pos subvi vi D Short Fibre Puller Dual Motor Controls TL Move Relative Pos subvi vi Newport Move Absolute subvi vi D Short Fibre Puller Dual Motor Controls Newport Move Absolute subvi vi TL Move Absolute Pos subvi vi D Short Fibre Puller Dual Motor Controls TL Move Absolute Pos subvi vi Newport Get Current Position subvi vi D Short Fibre Puller Dual Motor Controls Newport Get Current Position subvi vi TL Get Current Position subvi vi D Short Fibre Puller Dual Motor Controls TL Get Current Position subvi vi TL Poll for Homing Finished subvi vi D Short Fibre Puller Dual Motor Controls
21. en O Shea For all the help and warm welcomes that made Glasgow feel like home thanks to everyone in the IGR and not especially Mike and Fiona Dr Siong Heng Alastair Grant Gail Jan and Sean Of course none of this would be possible without the support of the Lake Forest College physics department both faculty Dr Nathan Mueggenburg Dr Scott Schappe and Dr Michael Kash and students and my fantastic teachers Cynthia Billington and Judith and Preston Hayes and my supportive friends and my loving parents and brother and patient dog And lastly for being awesome travelling companions and just generally awesome people to hang around with for the little time we all had together an extra special thanks to Dustin and Sam 31 University of Glasgow IREU 2014 Alyssa Conway APPENDIX A O Laser Pulling Machine LabVIEW Program Screenshots A 1 Idle State Newport IMS 400LM High Performance Long Travel Linear Motor Stage controlled by XPS Q8 Motion Controller IP Address 192 168 0 254 Group Name Group Positioner Name Group1 Pos travels along positions 200 mm to 200 mm at velocities from 500 mm s to 500 mm s excluding 0 mm s with accelerations from 0 0001 mm s to 26 000 mm s ThorLabs MTS50 M ZB Motorized Translation Stage SN 417192 controlled by ThorLabs TDC001 APT DC Servo Controller SN 83823439 travels along positions 1 000 mm to 49 000 mm at velocities in range from 0 mm s to 24 mm s in either direction
22. fiber as the upper carriage pulls the upper end of the silica fiber up This pulling process 1s viewable in action via the attached video courtesy of Dr Alan Cumming and the University of Glasgow B Micro puller plans The micro puller is currently in development The general setup will be similar to that of the puller discussed in section III A but the new machine will pull one to twenty micrometer diameter thin fibers The machine will employ a 120 W CO laser with wavelength 10 6 micrometers The laser will be directed by the same optical arrangement described in section II A except instead of a rotating 45 degree gold mirror a stationary 45 degree gold coated cone will be used to direct the beam to the gold coated conical mirrors which will ultimately focus the beam at a point on the silica fiber Instead of two carriages mounted on the same double leadscrew tower two separate stages will be mounted as shown in Figure 8 The Newport IMS 400LM stage has a range of 400 mm a maximum velocity of 500 mm s and a maximum acceleration of 26 000 mm s and is driven by a three phase synchronous iron core linear motor The ThorLabs MTS50 Z8 motorized translation stage has a range of 50 mm a maximum velocity of 2 4 mm s and a maximum acceleration of 4 5 mm s and runs using a dual set of linear rails with continuously recirculating ball bearings The motion of the Newport and ThorLabs stages are controlled by a LabVIEW program written by the
23. he lowest stage for the small 50 mm diameter interferometer mirrors will employ a monolithic suspension of 20 micrometer diameter thin fused silica fibers Westphal et al SQL quantum Seis susp mirror coating seses thermo optic freq intensity eet end mirror cavity Total classical noise Noise spectrum m rtHz 5 5678 2 3 45678 2 3 45678 2 3 45 10 100 1000 Frequency Hz Figure 3 Noise spectrum of AEI 10 m prototype Photon shot noise dominates for frequencies greater than or equal to 200 Hz while quantum radiation pressure noise dominates for frequencies below 200 Hz via Westphal et al Figure 5 Another small prototype exists in the IGR at the University of Glasgow in Scotland that also aims to reduce quantum noise This interferometer will use one gram mirrors suspended on one micron thin silica fibers B Industrial applications University of Glasgow IREU 2014 Alyssa Conway Many industries that require reliable low loss thermally stable optical fibers can also use the silica fibers pulled from the new machine and the new pulling techniques utilized One such application would be in oil or gas sensing OFS III SETUP amp DESIGN A CQ laser fused silica fiber puller The Institute for Gravitational Research IGR at the University of Glasgow in Scotland developed created and tested a CO laser based fused silica fiber pulling m
24. hould have beeped twice if 1t correctly reset Alternatively select TUNING from the top menu then select Group Pos from the dropdown menu to temporarily set corrector parameters or use the automatic tuning A 3 2 Recommended default SGamma settings Velocity 5 000 000 E42 units sec 500 000 mm s Acceleration 2 600 000 E 4 units sec sec 26 000 000 mm s s Minimum Jerk Time 4 000 000 E 2 seconds 0 040 000 00 s Maximum Jerk Time 4 000 000 E 2 seconds 0 040 000 00 s B ThorLabs B Connection The ThorLabs MTS50 Z8 motorized stage is controlled by the ThorLabs APT DC Servo Controller TDC001 which interfaces with the ActiveX plugin in LabVIEW such that property nodes control the motion and settings of the stage The connection requires the serial numbers for the stage 417192 and the controller 83823439 18 University of Glasgow IREU 2014 Alyssa Conway B 2 Motion The ThorLabs stage moves according to a trapezoidal motion profile for which the user sets minimum and maximum velocities and the acceleration The stage can move by position either from the current position to the desired destination absolute move or by a defined increment relative move Or the stage can undergo jog motion for which a signal is sent to the stage to initiate motion that 1s controlled by the motion profile and the extrema parameters set by the user until another signal 1s sent to stop the stage The ThorLabs stage travels along po
25. ime delay and then initiate the ThorLabs stage to begin its jog motion However this time delay must be less than the time the Newport stage 1s set to move during its first set velocity It is possible but seems unnecessary to start the ThorLabs stage before the Newport stage To do so set the Delay TL Start ms After Newport control to zero and in the pull file set the first velocity to zero with the time set for the length of the advance B 2 Stop Presently 1f as recommended the last velocity in the pulling file is zero the upper motor will stop first even before the Stop state is entered and in the Stop state the 26 University of Glasgow IREU 2014 Alyssa Conway zero velocity is fed again to the Newport stage in most cases this will do nothing but it will stop the stage in case an error occurred and then the ThorLabs stage receives the stop command as well However if the user wishes to control the stopping of the Newport stage in relation to the laser or ThorLabs stage differently the last velocity can be non zero In this case the user must explicitly allow the file to be used a dialogue box will appear Then the user can introduce delays between stopping the stages and laser Note then the time to transition to the stop case would need to be considered as mentioned in V A 3 and both stages would move farther than calculated Furthermore if any delays are introduced the stages could move farther than their
26. ional debugging is necessary view errors before the STOP JOG sub VI not outside the loop unless looking for errors occurring NOT during the jog mode Errors may occur if trying to disconnect the Newport or other stages when an error is passed as true so a simpler way of disconnecting when an error occurs may be to invoke the Ki A method available in the General subpalette of the XPS Q8S palette VI CONCLUSION The goal remains to produce one to twenty micrometer diameter thin fibers for use in precision measurement experiments both for research into quantum noise limits for use in ground based interferometry in direct detection of gravitational waves as well as for industrial use The CO laser fused silica fiber micro pulling machine that will ultimately pull these thin fibers 1s currently in development at the University of Glasgow Presently the control program is written for both Newport and ThorLabs motorized stages and the first mounting parts are being machined and ought to be assembled within the month of August 2014 1f work continues at an ideal rate Future work includes completing the machining and assembly of the entire setup adding laser control to the 28 University of Glasgow IREU 2014 Alyssa Conway current motor control program and testing and adjusting the timing of moving the stages and laser to achieve consistently pulled thin fibers 29 University of Glasgow IREU 2014 Alyssa Conway SOURCES
27. ming reasons see section V B 2 this extra time should be considered Note that the time delay introduced from these programmatic transitions may or may not be consistent between runs of the VI If the delay 1s consistent the user need merely to keep the change in accuracy in mind If the delay is inconsistent which the programmer believes is more likely if only due to more possibilities of programmatic hang ups during the state to state transition then some degree of precision would be 25 University of Glasgow IREU 2014 Alyssa Conway sacrificed and this amount would vary depending on the velocity Thus the simpler solution remains that the zero velocity be included in the pulling file to immediately stop the Newport stage B Newport amp ThorLabs amp laser timing control B Z Start The Wait amp Start Jog state waits for the Laser Ready indicator to be true then waits for the time delay 1f entered Then the VI transitions to the Pulling state Here the ThorLabs stage motion can be delayed some time after the Newport stage begins motion or the other way around or they can start at nearly the same time with the Newport stage starting just before the TL stage on the order of milliseconds To start the Newport stage then the TL stage afterward the user can simply enter some millisecond time in the Delay TL Start ms After Newport control If jog motion begins for the Newport stage without errors the VI will wait for that t
28. mm gt Newport runs too far 2 A 4 5 Check File State ThorLabs Only 40 University of Glasgow IREU 2014 Alyssa Conway Manually set the maximum jog time for only the TL stage uses no file input ATL Current Position mm ATL Jog Direction gt ftTL Acceleration mm s gt ATL Min Vel mm s Check gt Calculated TL Total Jog Displacement mm ATL Max Vel mm s gt id H ftCalculated TL Jog Ending Position mm Set Max Jog Time ms TL runs too far 2 A Enter New Files amp Parameters State Id Enter New Files amp Params Makes only certain controls visible and enabled ithe user can either edit these parameters or initi jeg i parameters Enter New Parameters fe Idle v Start Pull Fy Wait amp Start Jog gt Enter New Files amp Params v Set Newport Move Parameters ELE Visible Set TL Move Parameters ELE TL Jog Direction Enter New Parameters ELE Delay Start Pull Time ms After Laser Start Pull Delay TL Start ms After Newport Only the Start Pull or Enter New Params buttons are available to click Delay TL Stop ms All other controls hidden and or disabled forcing the user to either use After Laser the current settings to initiate a jog sequence or to enter new parameters A 6 Wait amp Start Jog State 41 University of Glasgow IREU 2014 Waits for laser to be ready land will wait to transition to enable jog motion if the delay is turned o
29. n then transition to the pulling case to start jog motion and pull fibres Delay Pull After Laser frLaser Ready gt Alyssa Conway KI Wait amp Start Jog icin Delay Start Pull Time ms After Laser A 7 Pulling State A 7 1 Pulling State Newport Only Sets the control for Open Close shutter so that it will open n initiates a time delay before continuing to the pulling state Enter New Parameters Start Pull 7 umm The only visible clickable control is the Exit Program button 42 University of Glasgow IREU 2014 Alyssa Conway i Upper Newport Only gt ftNewport Current Position mm yuuuuuuuuuuuuuuuuuuuuuuuuuuuuuun Starts jog motion a f Newport motion is enabled this state also initiates changes in the jog parameters according to the file Reinit To Default entered by the user E F Timing between when the TL and Newport stages SAcceleration mm E begin motion can be changed see description and comments for more details on timing ftVelocity mm s gt i iteration Newport error fisize of arr gt i gt B Current Time ms Start Time ms ftMax Jog Time ms fStop Pull o start TL before Newport set the time delay 0 and in the pull file set the first velocity 0 with the time set for the leng Stop Pull Current State Only the stop button is available to click amp only the indicators are visibl
30. n the next section XPS User s Manual 79 Or the Newport stage can undergo jog motion which is defined by velocity 15 University of Glasgow IREU 2014 Alyssa Conway and acceleration which can be changed during motion and for which the end of motion is defined by setting the velocity to zero XPS User s Manual 83 The IMS 400LM travels along positions from 200 mm to 200 mm at velocities from 500 mm s to 500 mm s excluding 0 mm s with accelerations from 0 0001 mm s to 26000 mm s There are hardware limit switches built into the stage that prevent it from moving past its range regardless of the software controls in place A 3 Motion profiler In order to reduce mechanical resonance caused by abrupt changes in the moving system the XPS controller uses an SGamma motion profile as the example in Figure 12 shows instead of a classical trapezoidal velocity profile XPS User s Manual 71 Each positioner has an associated motion trajectory profiler and a PID corrector XPS User s Manual 169 170 in this case Stage IMS400LM Driver XPS DRV02 MotorDriverInterface AnalogAcceleration CorrectorType PIDFFAcceleration 16 University of Glasgow IREU 2014 Alyssa Conway Jerk Velocity 1000 1 500 Jerk Time i w Z 0 g 05 5 500 1000 0 0 0 1 0 2 03 0 0 1 0 2 0 3 Time s Time s Acceleration Position 20 10 2 D 05 2 10 20 0 0 1 0 2 03 0 0 1 0 2 0 3 Time s
31. nt moving X land the approximate displacement and end position Velocity or i f i Enter New Files amp Params Acceleration out of range size of arr i Calculated Newport Total Jog Displacement mm Max Jog Time ms m Calculated Newport Jog Ending Position mm ftNewport Current Position mm gt A Delay TL Start ms After Newport 2i d ATL Current Position mm gt Delay TL Start ms Time Delay too TL runs too far After Newport large ftTLJog Direction r Calculated TL i Total Jog Displacement mm RTL Acceleration mm s gt f TL Max Vel mm s gt Calculated TL TL Min Vel mm 9 Jog Ending Position mm A 4 2 Check File State Invalid Filepath Condition L4 Invalid filepath A 4 3 Check File State Error Transition 39 University of Glasgow IREU 2014 Alyssa Conway CDAD DAA AD DD AD ADD 5 8 9 9 ee Sal Sal Sal Sd Sal Sal 3 Sa al d LS ul Sal al al Sal Sal Sal oa S 0 0 09 DDD AD AD 5 0 AR AD 0 Check File amp calculate time to jog amp fPulling Dataset bt file d r A ENF inclined Velocity or i Acceleration b out of range 2 Last velocity S not zero 2 g gt ftsize of arr gt frsize of arr am File gt fCalculated Newport Jog Ending Position mm A BH P Time ms ld ft Newport Current Position
32. of Glasgow IREU 2014 Alyssa Conway Neck section 400 um diameter 800 um diameter thermoelastic 3mm diameter endfor thin fibre losscancellation region ease of welding Figure 2 Advanced LIGO fiber end pulled from 3 mm stock Cumming A et al Draft Figure 2 II MOTIVATION The CO laser micro pulling machine currently in development at the University of Glasgow in Scotland aims to produce thin silica fibers from one to twenty microns in diameter These thin fibers can be used in experiments investigating quantum noise sensitivities like the AEI or the small interferometer in Glasgow these thin fibers have industrial applications as well A AEI amp IGR Further increasing sensitivities of interferometric techniques is clearly a large focus among current research Several interferometric prototype facilities exist with aims to further increase these sensitivities by exploring noise sources at detection extremes For instance the Albert Einstein Institute in Hannover Germany is currently constructing the AEI 10 m prototype interferometer facility This prototype aims to among other things explore the extremes of shot noise and radiation pressure noise as University of Glasgow IREU 2014 Alyssa Conway shown in Figure 3 for future improvements to larger interferometer facilities and techniques The AEI prototype will use 100 g test masses with multi staged pendulum suspensions in a 10 m arm Michelson interferometer T
33. or relative positions hat follow an SGamma movement trajectory A Can set velocity acceleration to reach the velocity and minimum and maximum jerk times in SECONDS Newport Current Pos Move Velocity mm s Newport Current Pos Move Acceleration mm s Param Newport Pos Move Velocity mm s Newport Pos Move Acceleration mm s jt eee eee erence SS SSE SS SS SSE SSE SSE SSS SSE SESS Alyssa Conway iiir Newport Pos Move Params C z zzzzzzzzz zzzz A 3 2 Set ThorLabs All Movement Parameters State 37 University of Glasgow IREU 2014 Alyssa Conway wm cct TL All Move Params C Z Z zzzzzzzzzzzzz TL Acceleration mm 5 Csen TL Max Vel mm s TL Min Vel mm s E TL Current MinVel mm s sci L Current MaxVel mm s E ipse TL Current Acceleration mm s scr A 4 X Check File State A 4 Check File State Default Both Stages 38 University of Glasgow IREU 2014 Alyssa Conway to ensure the stages won t overrun Checks Input File or Manually set maximum jog time amp transitions to allow user to enter new files parameters or begin jogging Checks file to ensure the entered parameters B won t cause errors in moving the stages i Assuming first column is velocities i second column is accelerations and i Last velocity i False vj third column is the time spent at each velocity B not zero Calculates the approximate time spe
34. p 0 NOTINIT 4 9 63 6 3 50 Initialize 1 Initialize amp CalibrateEncoder 15 Emergency Brake 40 EMERGENCY BRAKING Notes The numbers in the boxes are the different group status In bold are the transitions called by API see below the others are internal transitions Motion Disable Error 41 Error MOTOR INIT Error Initialize Actuator Set motor on Error Error Error Error ANALOG DISABLE MOVING SLAVE TRACKING ENCODR_CALIB T T i T T Motion Done Spin Slave Tracking Enable 6 Abort Stop 10 Disable 12 Disable 14 Home Search 2 Move 7 Spin Parameters Set 9 Motion Following Move Disable 5 Error 3 4 Tracking Enable 13 NOTREF GrouplInitialize GroupMoveAbort GroupHomeSearch GroupKill or KillAll Group MoveAbsolute GroupSpinParametersSet Group MoveRelative GroupSpinModeStop GroupMotionDisable SpinSlaveModeEnable GroupMotionEnable SpinSlaveModeDisable GroupAnalogTrackingModeEnable GroupAnalogTrackingModeDisable GrouplnitializeWithEncoderCalibration GroupReferencingStart GroupReferencingStop Figure 11 State diagram of the XPS controller XPS User s Manual pg 68 A 2 Motion The Newport stage can move by position either from the current position to the desired destination absolute move or by a defined increment relative move all following the SGamma set parameters as explained i
35. port Pos Move Velocity mm s Newport Current Pos Move Veloci ft Newport Pos Move Acceleration mm s ft Newport Current Pos Move Acceleration mm s gt epending on whether checking the input file ERR Set Newport Move Parameters i Max Jog Time ms mize MR REM gt Blinking M Visible M Fr Visible Set Max Jog Time ms mm s ree NDDDDOSSSSSOSASSOSASSOAOSSSSSOSJSOOQOSAJOJAZJADSSOSOSSSSOSAAODSSSDOSSOSOSOOJSSOOOOSOZOZJOSOSOOAJAOOSSOASOSOSOOAOAOOOJSSOOSASJAOSSSAOJASOOSSOSSOSZ2OSOSOZOSOOSSOSOSOSASJSAOAOOJSOZSJOSOOSAOSOJOJAOOASZSOOSSOZSAOSOSOJSOSOSSSASASSSOSSSOOOSSSSE KAA AAAA AA A kk SA SA SA SA SA SA SASA SA SA SSR SA SA SA SA Sk SA SN SA GA SA SA SA SA SA SA SA SA SA SA SA SA SA SA CA SSA SA SA Sk SASA SSS SA SA SA SSA SA SA SA SOR SA SA SA A SA SA A SA SA SA CA OA SA SA CA SA SA SA CASA SA SA SS SASA SA OA SR OA SA GA SA OA SSR eee eee SA SA A SA SA SA S SA SASA SA aS SASA SA SA CA SA SA SA OE SA SA SA Sk SASA OA SA Sak SA SA SA A SA SA Sk SASA Sk SA SA SA SS SA SA SA ak SA ASA SA CASA AS A 1 2 Idle State ThorLabs Only 33 University of Glasgow IREU 2014 LLL LLL LAA EAL EE EL LL ALLL EE AE EE EE LLL EAA LAL EE EEE EEE EEE OE EEE Lower ThorLabs Only Checks whether user set movement parameters match the actually set parameters ATL Current MinVel mm s gt ATL Min Vel mm s gt on the current position TL Relative Displacement mm ET 5 KAADA
36. rooping in the fiber are minimal at this time Furthermore if the Newport stage is moving quickly enough and the lower motor Thorlabs stage moves so slowly in comparison the Thorlabs stage may even remain stationary during the pull the option to move each stage independently is available in the current control program Figure 9 CAD rendering of micro fiber pulling machine courtesy of Dr Liam Cunningham and Russell Jones 13 University of Glasgow IREU 2014 Alyssa Conway Figure 10 CAD rendering of micro fiber pulling machine courtesy of Dr Liam Cunningham and Russell Jones IV EQUIPMENT A Newport A J Connection The Newport IMS 400LM motorized stage is controlled by the Newport XPS DRV02 Driver which interfaces with the subVIs used from Newport built libraries grouped into the folder called XPS Q8 that have been loaded into this version of LabVIEW The connections among LabVIEW the XPS controller and the stage require the IP Address currently 192 168 0 254 the Group Name Group1 and the Positioner Name Groupl Pos The Newport Connect amp Initialize amp Home subvi shows the 14 University of Glasgow IREU 2014 Alyssa Conway required sequence necessary to connect the stage and enable the ready state see also State diagram of the XPS controller on page 68 of XPS User s Manual or Figure 11 here from which the desired motion states can be entered Initial KillAllGroup 8 Emergency Sto
37. sitions 1 000 mm to 49 000 mm at velocities in range from 0 mm s to 2 4 mm s and accelerations from 0 0001 mm s to 4 500 mm s The stage can travel in either direction which is set by a switch not by entering negative speeds which will return an error The ThorLabs stage has hardware limit switches that stop the motion from continuing past the range limits regardless of the software settings V DUAL MOTOR CONTROL PROGRAM The control program was written using National Instruments LabVIEW 2013 SPI 64 bit LabVIEW is a data flow oriented C programming language with a graphical interface especially useful for connecting and controlling machinery The program code is created on the block diagram which includes subVIs methods and control structures loops conditionals that have inputs and outputs wired together like an electrical circuit that executes according to what data 1s available Cumming Thesis 224 The user interacts with the front panel which includes controls buttons number inputs and indicators number outputs graphs flashing lights 19 University of Glasgow IREU 2014 Alyssa Conway The VI control program called Short Fiber Puller Acceleration amp Time File Summer 2014 controls the movement of the Newport and ThorLabs stages and contains enough flexibility to someday include control of the laser as well Figure 13 below shows the general progression of the block diagram First both stages are connected an
38. t Acceleration mm s Reinit To Default Newport Current Pos Move Velocity mm s Reinit To Default Newport Current Pos Move Acceleration mm 5 Reinit To Default Reinitialize these parameters to default each time the VI is called so that the user must set the velocities and accelerations leach time the stages are connected otherwise the parameters will return to the default values 22 University of Glasgow IREU 2014 Alyssa Conway MGL7Motor A Newport jog control Short Fibre Puller Dual Motor Control 0 BEFORE Running VI select DO NOT M ove Motor 24 1 Set Movement Parameters Move Params Done Jog Controls Laser Shutter Input Leser Ready C gt ON Open Close Shutter C gt ON NEWPORT Newport Pos Move Acceleration mm s 4 26000 000000 Newport Pos Move Velocity mm s br 500 000000 9 Sets acceleration amp veloc ty for moves by position only TL Min Vel mm s ny g L TL Max Vel mm s 212 TL Acceleration mms A 2 Move by Position THORLABS TL Jog Direction UP 4 Sets acceleration amp velocity extrema for all movement both moves by position amp jog moves Newport Target Absolute Position mm J 193 000000 TL Target Absolute Position mm 30 7 TL Re Newport Relative Displacement mm 20000000 ative Displacement mm 0 ADVANCE AFTER PULL Jog Timing
39. t of the Newport stage only by extension the cumulative amount of time the Newport stage moves is approximately the same amount of time the ThorLabs stage moves although its movement and speed are set separately The pulling file should be a text file with three columns Ist Velocity mm s 2nd Acceleration mm s 3rd Time ms 23 University of Glasgow IREU 2014 Alyssa Conway Text files should have only numbers and be tab delimited copy and paste from excel works fine For corresponding rows indices the Newport stage will move at the constant velocity for the corresponding time and will accelerate from the previous velocity to reach the new velocity using the corresponding acceleration For example consider two rows from some file labeled for convenience Vel Accl Time 300 2500 2000 row 5 400 5000 1000 row 6 When executing row 6 the Newport stage will accelerate at 5000 mm s from an initial velocity 300 mm s to reach the velocity of 400 mm s which should take about timeacc vf v0 a 20 ms Then the stage will move at the constant velocity 400 mm s for timevel 1000 ms As a result the stage will move approximately x vf timevel 0 5 a timeacc 2 400 1 0 5 5000 0 02 2 400 mm 1 mm 401 mm This example however would move the Newport stage beyond its 400 mm range Thus the Check File state checks that any such errors are caught and does not allow the user to initiate jog mode un
40. the mirror and the connections between them One low loss high dilution material that has been used 1n quasi monolithic suspension systems for GEO600 and aLIGO 1s silica Present research in this paper focuses on reliably producing fused silica suspension fibers for use in precision measurement experiments Previous efforts have used hydrogen oxygen flames to pull silica fibers however particulates introduced from byproducts of this method can introduce defects into the surface of the fiber and increase noise In addition uneven heating can induce cracks in the silica which further increase thermal noise Thus this method has been replaced by the use of a CO laser for more even reliable heating with a better system of feedback from the use of a laser The Institute for Gravitational Research IGR at the University of Glasgow in Scotland developed created and tested a CO laser fused silica fiber pulling machine capable of creating fibers that meet strength thermal noise and dimensional tolerance requirements for aLIGO generation gravitational wave detector mirror suspensions Heptonstall et al The resulting fibers are 380 micrometers in diameter at their thinnest central section Heptonstall et al Figure 2 shows similar fibers with diameters of 400 micrometers from the draft by Cumming et al Current efforts focus on creating a micro fiber pulling machine that will produce fibers one to twenty micrometers in diameter University
41. til the file and current parameters of the stage will not cause errors see section V C for more on error checking A 2 Distance calculation 24 University of Glasgow IREU 2014 Alyssa Conway It is important to note that this distance calculation only agrees with the actual distance travelled by the Newport stage on the order of one millimeter However the repeatability of the stage under identical settings for each parameter and pulling set 1s on the order of tens of microns In other words for each pulling file or parameter set the stage travels consistently to the same ending position within about 0 04 mm In summary motion is repeatable to an accuracy of approximately 1 mm and to a precision of about 0 04 mm A 3 Stop considerations in file entry In order to stop the Newport stage immediately or as close to the desired time distance as possible the user should include zero as the last velocity in the jog control pulling file If the stage 1s moving at fairly large velocities even a small time delay from transitioning states in the LabVIEW state machine could cause a significant change in ending position For example if the velocity 1s 250 mm s just half of its maximum the stage could move 2 5 mm in just 10 ms Clearly this distance in non negligible if our aim is on the order of microns or tens of microns of precision If the user would rather not include the immediate stop of the Newport stage in the pulling file for ti
42. ving carriage moving clamp drawn silica fiber lower moving carriage upper conical mirror horizontal ballscrew unit fixed clamp fixed 45 degree mirror rotating 45 degree mirror drive motor fixed conical mirror Figure 4 SOLIDWORKS rendering of the fiber pulling machine in cylindrical fiber configuration via Heptonstall et al Figure 4 University of Glasgow IREU 2014 Alyssa Conway drawn silica fiber _ BU vertical CO laser beam rotates and reflects off moving upper conical mirror to heat stock uniformly around 360 degrees SA SP p fixed 45 degree mirror fixed lower conical mirror rotating 45 degree mirror Figure 5 SOLIDWORKS rendered drawing of the laser beam delivery for cylindrical fiber production via Heptonstall et al Figure 5 University of Glasgow IREU 2014 Alyssa Conway Figure 6 Photograph of fiber puller optical setup CO laser delivered through articulated arm ZnSe output telescope and a pair of mirror galvanometers via Heptonstall et al Figure 9 University of Glasgow IREU 2014 Alyssa Conway Figure 7 Photograph of fiber puller at the University of Glasgow courtesy of Dr Alan Cumming and Russell Jones When pulling a cylindrically shaped fiber the lower carriage with the upper conical mirror can move up slowly to focus the laser and heat different positions on the 10 University of Glasgow IREU 2014 Alyssa Conway silica
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