PHOSPHOR THERMOMETRY TECHNIQUES FOR THE REALIZATION OF THERMAL STANDARDS

The possibility of using single-crystals of thermographic phosphors in a new realization of the degree kelvin has been explored. The experimental technique would involve the laser-induced fluorescence of a rare-earth-doped phosphor, the optical decay lifetime of which would be measured relative to an atomic clock, in order to obtain a primary standard of temperature based only on atomic quantities. In principle the technique could provide the first realization of the kelvin over continuous ranges of temperature, without the need for interpolation between fixed thermodynamic transition points. Possible experimental arrangements for carrying out such a realization of the degree kelvin will be discussed.

By:           Allison, S.W., Beshears, D.L., Gillies, G.T.
Date:         August 2002
Distribution: Published
Formats:      pdf (165KB)
Filename:     48th ISA Symposium Paper

RECENT DEVELOPMENTS INVOLVING THERMOGRAPHIC PHOSPHORS

In the past year we have made significant advances in identifying and testing short-decay time phosphors, testing high temperature binder materials, testing phosphors to very high temperatures, and measuring microcantilever temperatures.  We tested a variety of cerium-doped phosphors, which, prior to quenching, exhibit decay times of 60 ns.  The short decay means such phosphors are particularly good for imaging surfaces moving at high speeds.  A new binder combination was mixed with any of several YAG phosphor compounds, and showed good adherence to at least 1000 C.  Testing will shortly commence to 1500 C.  Microcantilevers are key components of many MEMS (microelectromechanical systems) devices.  We attached phosphor to one such cantilever.  The piezoresistive cantilever heated with application of a current.  The temperature rise was approximately 500 C for about 5 ma.

By:           Allison, S.W., Beshears, D.L., Cates, M.R.
Date:         August 2002
Distribution: Published
Formats:      pdf (338KB)
Filename:     9th Pressure Sensitive Paint Conference Paper

PHOSPHOR THERMOMETRY TECHNIQUES FOR THE REALIZATION OF THERMAL STANDARDS (PRESENTATION)

This presentation was given at the 48th ISA Symposium, held in San Diego, CA. May 6-9, 2002.  The presentation was based on the paper entitled: PHOSPHOR THERMOMETRY TECHNIQUES FOR THE REALIZATION OF THERMAL STANDARDS

By:           Allison, S.W., Beshears, D.L., Cates, M.R.
Date:         August 2002
Distribution: External
Formats:      pdf (2.03MB)
Filename:     48th ISA Symposium Presentation

HIGH TEMPERATURE SURFACE MEASUREMENTS USING LIFETIME IMAGING OF THERMOGRAPHIC PHOSPHORS:  BONDING TESTS

Temperature-sensitive paint (TSP) comprised of thermally sensitive phosphor can provide a viable means for noncontact thermometry in wind tunnel and other aeropropulsion applications.  Described here are recent results aimed at developing a phosphor and binder system that will cover a wide temperature range, ambient to 1000 C.  The phosphor/binder mixture is to be sprayed directly on the surface with an airbrush.  Whereas many surfaces are candidates for various uses, the present effort concerned silicon carbide, silicon nitride and silica substrates.  Initial tests show that a phosphor mixture with two water-soluble materials, designated LK and HPC and manufactured by ZYP Inc., adhered well to these substrates.  This same material was earlier shown to function well on a high strength nickel alloy.

By:           Allison, S.W., Beshears, D.L., Gadfort, T., et. al.
Date:         August 2001
Distribution: Published
Formats:      pdf (325KB)
Filename:     NASA Paper 1

Development of Temperature-Sensitive Paints for High Temperature Aeropropulsion Applications

Fluorescence from a phosphor coating will indicate the temperature of the substrate to which it is attached, assuming thermal equilibrium is achieved. The goal of this investigation is to identify phosphors for making temperature measurements on aerospace surfaces with temperatures varying from ambient to 1000o C and to identify and test binders/adhesives that may be mixed with thermographic phosphors and sprayed onto surfaces of interest to provide a durable and uniform coating. The surfaces of interest include various high-strength metal alloys, such as stainless steel and nickel with and without thermal barrier coats, ceramics, carbon/carbon composites, and copper.

By:           Allison, S.W., Beshears, D.L., Bencic, T., et. al.
Date:         July 2001
Distribution: Published
Formats:      pdf (326KB)
Filename:     AIAA Paper 3528

SUB-MICROSECOND DECAY TIME PHOSPHORS  for Pressure Sensitive Paint Applications

The purpose of the effort described herein is to identify and characterize thermally sensitive phosphors of potential use to pressure-sensitive paint (PSP) applications.  Some PSPs show a pronounced dependence on both temperature and pressure.  Pressure dependence of a phosphor is negligible.  Thus a phosphor can unambiguously indicate temperature.  A suitable combination of a PSP and a phosphor can therefore potentially provide for both pressure and temperature measurement.

By:           Allison, S.W., Beshears, D.L., and Cates, M.R.
Date:         May 2001
Distribution: Published
Formats:      pdf (306KB)
Filename:     ISA Paper 471

Dyanmic Pressure of Liquid Mercury Target During 800 MeV Proton Thermal shock tests

Described herein are efforts to diagnose transient pressures generated by a short-pulse (about 0.5 microseconds) high intensity proton (~ 2 * 1014 per pulse) beam.  Proton energy is 800-MeV.

By:           Allison, S.W., Beshears, D.L., and Cates, M.R., et.al.
Date:         May 2000
Distribution: External
Formats:      pdf (753KB)
Filename:     ORNL/TM-2000/46

A Survey of Thermally Sensitive Phosphors for Pressure Sensitive Paint applications

We discuss selection and testing to thermally sensitive phosphors for use with pressure-sensitive paints (PSP's).  These phosphors exhibit essentially no pressure dependence and therefore, can provide an independent means for removing the temperature-dependent response of PSP's.

By:           Allison, S.W., Beshears, D.L., and Cates, M.R.
Date:         May 2000
Distribution: External
Formats:      pdf (49 KB)
Filename:     ISA Paper 472 

Application of Phosphor thermometry to a galvanneal temperature measurement system

The Galvanneal Temperature Measurement System (GTMS) was developed for the American Iron and Steel Institute by the Oak Ridge National Laboratory through a partnership with the National Steel Midwest Division in Portage, Indiana.  The GTMS provides crucial on-line thermal process control information during the manufacturing of galvanneal steel.

By:           Allison, S.W., Beshears, D.L., and Cates, M.R. et. al.
Date:         April 2000
Distribution: External
Formats:      pdf (705 KB)
Filename:     GTMS 

excitation of thermographic phosphors using a blue led: spectral characteristics and instrumentation applications

A blue light emitting diode (LED) has been used as the excitation source in a series of sensor-related characterization studies carried out on thermographic phosphors.  The motivation for the described effort is the potential utility of light emitting diodes for fluorescence based thermometry applications.

By:           Allison, S.W., Cates, M.R.
Date:         May 1999
Distribution: External
Formats:      pdf (172 KB)
Filename:     ISA Paper 473 

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