SURFACES OF ELECTRON-EMITTING GLASSES STUDIED BY A SLOW POSITRON BEAM

D. Pliszkaa, M. Gazdab, B. Kuszb, K. Trzebiatowskib, G.P. Karwaszc, W. Dengc, R.S. Brusac and A. Zeccac aInstitute of Physics, Pedagogical University, Arciszewskiego 22B, 76-200 Słupsk, Poland bFaculty of Technical Physics and Applied Mathematics, Technical University Narutowicza 11/12, 80-952 Gdańsk, Poland cIstituto Nazionale per la Fisica della Materia, Unita' di Trento, 38-050 Povo, Italy

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Semi-conducting glasses used for electron multipliers and microchannel plate devices are obtained by surface modification of Pb or Bi-reach silicon-based glasses. The reduced layer extends down to 200-500 nm, much more than the effective depth of the electron-emitting layer. By the use of slow-positron beam we monitor the structural changes undergoing in near-to-surface layers after isothermal annealing. The measurements suggest a possible correlation between secondary-electron emission coefficient and the Doppler-broadening S-parameter. On these samples there were also performed atomic force microscopy, secondary electron emission, differential scanning calorimetry, and electric conductivity measurements.

DOI: 10.12693/APhysPolA.99.465 PACS numbers: 71.60.+z, 78.70.Bj