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Measurements of the relative transmission properties of optical fiber for use on Proto-MPEX. Presented at the 56th APS Division of Plasma Physics Meeting New Orleans, LA, USA, October 27th – 31st, 2014 T.M. Biewer1, K. Collins2, B. Johnson3, A.  Lancaster4, R. Mosby5, H. Ray1, G. Shaw1,6, B. Young7 1Oak Ridge National Laboratory, Oak Ridge, TN 2Monroe County High School, Tompkinsville, KY 3Wilkes Central High School, Wilkes County , NC 4Allegany High School, Cumberland, MD 5Oak Ridge High School, Oak Ridge, TN 6University of Tennessee, Knoxville, TN 7Clay County High School, Clay, WV

JP8.00006

2 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014

Abstract The prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device being developed at Oak Ridge National Laboratory (ORNL). This machine plans to study plasma-material interaction (PMI) physics relevant to future fusion reactors. Measurements of plasma emission will be made on Proto-MPEX using spectrometers and filterscopes, which are couple to the plasma by fiberoptic cables. The transmission properties of these fiberoptics are critical to the accurate estimation of the plasma emission levels. This presentation will highlight some of the issues encountered during calibration of hardware for use on Proto-MPEX.

This material is based upon work supported by the U.S. D.O.E. Office of Science under Award Number DE-AC05-00OR22725.

3 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014

• 2014 High School Summer Math-Science-Technology Institute –  July 5-19, 2014 at Oak Ridge National Lab. –  http://www.orau.org/arc-ornl/2014/index.html

• Applications will be accepted for 2015 beginning in December through the state program managers of the Appalachian Regional Commission –  http://www.arc.gov/program_areas/

ARCOakRidge2014SummerPrograms.asp

High School Summer Science Program

4 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014

ARC/ORNL 2014 Team

6 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014

OVERVIEW

• Plasma: What is it? –  Fusion

•  ITER and Proto-MPEX • Diagnostic Systems: Why, What, and How?

–  Relative Transmission

• The Investigation –  Data and Results –  Conclusions & Significance –  Summary

• Acknowledgements

7 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014

Plasma: The 4th State of Matter

o  a collection of electrons and atomic nuclei that occurs when an element is heated beyond the gas phase

o  Gas/Fluid like motion (Navier-Stokes Equation) Electrically conductive (Maxwell’s Equations)

Solid

Plasma Liquid

Gas

8 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014

Fusion

What is Fusion? o  Fusion is a nuclear process in which light nuclei fuse together. The temperature at which fusion occurs

is where plasma is formed.

Why is it Important? o  Inexhaustible o  Better for the Environment o  Safer than Fission

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Ant-ITER

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ITER

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JET

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Proto-MPEX

o  Proto-MPEX is a linear plasma device used to study plasma material interactions (PMI) for future nuclear fusion devices (such as ITER).

o  ITER is the world’s biggest International

Collaboration for future energy and includes China, The European Union, India, Japan, South Korea, Russia, and the United States.

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Diagnostics Systems: Why, What, and How?

o  Fiber Optics

o  To transfer light emissions of plasma produced by proto-MPEX to the Spectrometer to be studied

o  Couplers

o  To connect fibers and transmit light emissions across greater distances

o  Spectrometer

o  To read the spectrum of light produced and record data o  Labsphere

o  A proxy for the light that will be emitted from Proto-MPEX during normal operation

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15 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014

Relative Transmission

o  Relative transmission is how well a fiber optic cable transfers light.

o  To calculate the relative transmission: o  Measure a fiducial (starting light transmission

without a cable) and then measure each individual cable.

o  Divide the cable transmission by the fiducial transmission. The quotient of the two is the relative transmission.

16 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014 Infrared

0

0.2

0.4

0.6

0.8

1

1.2

450.0000 500.0000 550.0000 600.0000 650.0000 700.0000 750.0000 800.0000 850.0000 900.0000

Data and results

Graph of Fiber A_03 Wavelength (nm)

400 500 550 600 650 700 750 800 850 900

Rel

ativ

e Tr

ansm

issi

on

Ultraviolet

17 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014 Infrared

0

0.2

0.4

0.6

0.8

1

1.2

450.0000 500.0000 550.0000 600.0000 650.0000 700.0000 750.0000 800.0000 850.0000 900.0000

Graph of Fiber B3_02 Wavelength (nm)

400 500 550 600 650 700 750 800 850 900

Rel

ativ

e Tr

ansm

issi

on

Ultraviolet

Data and results

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Relative Transmissions

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 20 40 60 80 100 120 140 160 180

Relativ

e  Tran

smission

Fiber  Number

Relative  Transmissions  

532

656

19 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014 0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 10 20 30 40 50 60

Comparison of Coupler Transmissions

Fiber Number

Cou

pler

Tra

nsm

issi

on

TC= TT/(TA*TB)

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Conclusion o  The transmission of 156 individual fibers were

measured o  Some fibers transmitted better than others at

separate wavelengths o  The transmission of 60 coupled fibers were

measured o  From these, the transmission of the couplers

was calculated o  When collecting data from Proto-MPEX, it is

important to keep track of the specific fiber and couplers that are being used.

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Significance

o  Without calculation of each fiber, inaccurate measurements for light transmission could occur

o  The diagnostic system must be calibrated in

order to meet experimental conditions

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The Investigation: Summary o  A spectrometer was used to measure plasma emission

that will be made on Proto-MPEX o  Data was transferred to the computer by connecting

fiber optic cables to a labsphere and a spectrometer o  Excel was used to plot data and find the relative

transmission between the fiducial and each cable. o  Cables were then connected using a coupler o  The relative transmission was once again found, and

the mean value of each cable was found to compare all transmissions and wavelengths for the best cable

23 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014

Acknowledgements

o  Jeff Schwartz o  Jennifer Tyrell o  ORAU o  Theodore (Ted) Biewer o  Guinevere (Guin) Shaw o  Holly Ray o  ORNL o  ARC

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The End

25 T.M. Biewer, et al, APS 2014, New Orleans, LA, USA, October 30th, 2014

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