Investigating Thermal Shock*
Fran Morrissey
 DOE ERULF
Kutztown University
Oak Ridge National Laboratory
Oak Ridge, Tennessee 37830

April 29, 1999
CONCLUSIONS

Fabry-Perot Interferometric Strain Sensor

Demonstrated functionality with qualitatively similar results under similar strain. Obtained data detailing deformation on the target wall. This deformation is characterized by an oscillation of the cavity wall, which transgresses into a steady state that eventual reaches equilibrium.

Phosphor Temperature Sensor

Demonstrated that the system was successful in producing laser excited fluorescence signals during the interaction with the proton beam. The beam was found to excite fluorescence with no phosphor degradation after 37 shots. By pulse averaging, it was possible to obtain transient temperature measurements both before and after beam arrived. Using this technique, temperature fluctuations of the mercury were shown to vary by approximately three degrees during data acquisition.

High Sensitivity Diaphragm Pressure Sensor

Demonstrated functionality of both high and low pressure diaphragm sensors, with excellent signal to noise characteristics. Obtained data showing variation in mercury target pressure after the beam shot. The pressure observed is characterized by an oscillation of the mercury within the cavity due to interaction with the proton beam. The oscillatory nature of the data obtained from the strain sensors located on the cavity walls is in accordance with the pressure data which is based on the response of the mercury to the proton beam.

BIBLIOGRAPHY

1. R.O. Claus, M.F. Gunther, A.B. Wang, K.A. Murphy and D. Sun, "Extrinsic Fabry-Perot Sensor for Structural Evaluation," Applications of Fiber Optic Sensors in Engineering Mechanics, 1993, pp. 60-70.

2. S.W. Allison, G.J. Capps, D.B. Smith, M.R. Cates, W.D. Turley, J. Gleason, "Thermographic Phosphor strain Measurements," Research Project 8004-3, U.S. Department of Energy, February, 1994, pp. 1-8.

3. S.W. Allison, G.T. Gillies, "Remote thermometry with thermographic phosphors: Instrumentation and applications," Review of Scientific Instruments, American Institute of Physics, Vol. 68, No. 7, July 1997, pp. 2615-2650.

SUMMARY

During neutron spallation experiments at Los Alamos Neutron Science Center, a target cavity filled with mercury was examined using various sensing equipment developed by the Engineering Technology Division, this included fiber optic strain sensors, phosphor temperature sensors, and high sensitivity fiber optic diaphragm pressure sensors. The goal is to determine the characteristics of the target container and cavity which contains liquid mercury. The pressure and temperature of the mercury, along with the strain on the cavity, was measured during its interaction with a 10^13 proton pulse, which had proton energies of approximately 0.8 GeV.

All sensing systems demonstrated functionality in producing temperature, pressure, and strain measurements. The phosphor sensor detailed variations in temperature during transient measurements, before, during, and after the beam interaction with the mercury target. The diaphragm pressure sensor divulged that the mercury underwent oscillations in response to the proton beam. This is in agreement with the oscillation of the cavity walls as presented by the strain sensor data.

ACKNOWLEDGMENT

Photonics and Measurement Systems Group
 Engineering Technology Division
United States Department of Energy

  • Dr. Steve Allison, Mentor
    As my advisor, he supervised the main thrust of the research conducted at Oak Ridge National Laboratories. He provided direction for the majority of the details concerning all aspects of the complexities of Fluorescence-Based Thermometry. After completing the preliminary temperature studies from the data at Los Alamos, with his help, over 20 phosphors were thoroughly investigate for their decay time temperature dependence. His help was also invaluable concerning the formulation of the final paper presented to ORISE, my poster presentation to ORNL, and my formal ERULF presentation! WEBSITE: http://www.ornl.gov/sci/phosphors/index.htm

  • Dr. Mike Cates
    Most of my interaction with Dr. Cates was concerning the Fiber Optic Strain Sensing Equipment. Many hours were spend in his office working out the details for accurately interpreting the interferometric signal. With his help along with Dr. Jim Tsai and Duncan Earl, results were finally obtained!

  • Duncan Earl
    Duncan Earl's lab was were the majority of research work was completed; including both the calibration investigations and the data analysis. He is the primary contributor to the project for the strain sensing data acquisition application. Currently pursuing a Electrical Engineering Degree at the University of Tennessee. Even though he often would arrive at the lab in the afternoon, I seemed to arrive from lunch just at the right time to bump into him. He also helped me change my dead battery that was rusted to the interior of my engine!

  • Dave Beshears
    Had completed a number of phosphor calibrations under the direction of Mr. Beshears for an industrial application to be completed in the near future. With his assistance, I became immediately acclimated to the phosphor experimental setup.

  • Doris Shubert
    Doris was invaluable to my workings for the ERULF program. She assisted in obtaining materials and services for both office and computer needs. She also assisted in the making of overheads for various presentations to the SNS project group at ORNL and the ERULF/ORISE seminar. It would have been impossible to be completely prepared for these events without her assistance!

    Fusion Energy Division
    United States Department of Energy

  • Dr. Jim Tsai
    Dr. Tsai and myself, worked closely with the stain data from both Los Alamos and Brookhaven National Laboratories. Attacking the data from slightly different directions we were able to compare our finds and ultimately obtain accurate results.

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