Wüest M. 51 Wykes M. 82 Yamaguchi M. 17 Ybarra G. 129 Yubero F ...

JUNE 28 WEDNESDAY MORNING
RIVA-SS-WeM-OR.1 USE OF A RADIO-FREQUENCY POWER SUPPLY COUPLED
TO A HIGH TEMPERATURE FURNACE IN ULTRAVIOLET PHOTOELECTRON SPEC-
TROSCOPY. E. M. C. C. Reis 1,2 , A. A. Dias 1,2 , O. M. N. D. Teodoro 1,2 and M. L. Costa 1,2 . 1 Centre
for Physics and Technological Research, CEFITEC. 2 Departamento Física Faculdade de Ciências e
Tecnologia, Universidade Nova de Lisboa, Monte de Caparica, 2829-516, Caparica, Portugal. e-
mail: aad@fct.unl.pt
Temperatures up to 2500 ºC have to be attained for analysing solid samples by Ultraviolet Photoelectron
Spectroscopy (UVPES), using a high temperature furnace[i]. A radio-frequency (RF) power
supply seems ideal for this purpose [ii].
The RF source, operating near the photoelectron spectrometer, creates an electromagnetic field that
causes interference in photoelectron trajectories. In order to eliminate this effect the RF power supply
should be used in a pulsed mode in conjunction with a linear gate in detector circuits.
The frequency chosen to obtain these pulses is of 50 Hz, since that is the frequency used by the
mains. The 50 Hz waves are rectified, being allowed to pass only the positive voltages, eliminating
the negative ones.
Considering that the maximum power available from the generator is reduced to less than half of its
original value, as a result of the pulses, a considerable amount of power is necessary to raise the
temperature.
Modifications performed in both a RF power supply and detector circuits, together with its coupling
to an existing high temperature furnace will be presented.
References
[i] J.M. Dyke, G. Levita, A. Morris, J. S. Ogden, A.A. Dias, M. Algarra, J.P. Santos, M.L. Costa,
M.T. Barros, J. Phys. Chem. A 2004, 108, 5299-5307.
[ii] D. Bulgin, J. Dyke, F. Goodfellow, N. Jonathan, E. Lee, A. Morris, J. Elec. Spec. Rel. Phen.
1977, 12, 67-76.
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