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Temperature course in small volume [18O]water targets for [18F]F- production
J Steinbach1, K Guenther, E Loesel
1Academy of Sciences of the G.D.R., Central Institute of Nuclear Research Rossendorf, Dresden.
International Journal of Radiation Applications and Instrumentation. Part A, Applied Radiation and Isotopes
|January 1, 1990
Summary
High beam currents cause static water targets to reach boiling point. Heat transfer primarily occurs via molecule movement, not conduction or convection, at these temperatures.
Area of Science:
- Thermal Physics
- Fluid Dynamics
- Materials Science
Background:
- Understanding heat transfer in water targets is crucial for applications involving high-energy beams.
- Previous models did not fully account for thermal processes at boiling point under irradiation.
Purpose of the Study:
- To investigate the thermal processes in small volume water targets under high beam currents.
- To compare heat transfer calculations with experimental temperature measurements.
Main Methods:
- Performed heat transfer calculations for beam energy absorbed by water targets.
- Measured target water temperatures during irradiations.
- Analyzed heat transfer mechanisms including conduction, convection, and molecular movement.
Main Results:
- Experimental and calculated results indicate water targets reach boiling point at high beam currents.
- Heat transfer is dominated by the movement of water molecules generated by boiling.
- Conduction and free convection alone are insufficient to explain the observed heat transfer.
Conclusions:
- Static small volume water targets operate at boiling point under high beam currents.
- Boiling-induced molecular movement is the primary mode of heat transfer, overriding conduction and convection.
- Vaporization and reflux do not significantly contribute to heat transfer in this scenario.