S. Kaszczyszyn

Atomic force microscopy and friction force microscopy studies of ferroelastic crystal surfaces

Abstract Topography and frictional properties of freshly cleaved surfaces of ferroelastic crystals: K 3 Na(SeO 4 ) 2 (KNSe), and NH 4 LiH 3 (SO 4 ) 4 (ALHS), and Gd 2 (MoO 4 ) 3 (GMO) were investigated by combined scanning and friction force microscopy (FFM) under ambient and UHV conditions. Atomic force microscopy (AFM) images revealed stepped surfaces with step heights corresponding to the multiplication height of crystal lattice constant fractions e.g., c /2 or c /4. A frictional contrast was observed between terraces which are separated by steps and between different domains of ferroelastic crystals. We suggest that the frictional contrast is due to different molecular orientations at different terraces and/or at different domains of a ferroelastic crystal, in the case of GMO, surface bends at the domain boundary with the angle estimated to be about 2.35°. It was also shown that the ALHS crystal surface can be modified (e.g., by changing the step profile and creation of the artificial bumps) by an AFM tip imaging with normal force above 100 nN.

AFM investigation of bismuth doped silicate glasses

Abstract Bismuth doped glasses were reduced in hydrogen atmosphere at temperatures above 250 °C. This process leads to changes in stoichiometry of the glass in the region close to the glass surface. Relatively high surface conductivity of 10 −6 S allows this material to be applied to channeltron production. AFM investigations of freshly cleaved bismuth doped glasses were done in constant and friction force modes. The AFM topographical images show the presence of different concentrations of nanocrystals vs distance from the glass surface. Atomic resolution images obtained in both modes of these nanocrystals, together with XRD data, suggest that they are composed of bismuth.

Flicker noise of the channel electron multiplier

Abstract The spectral density function of the channel electron multiplier noise has been investigated. The existence of flicker noise ( 1/f α ) has been shown. Changes of the exponent α versus the multiplier current have been observed and the relationship between them has been established.

AFM investigations of K3Na(SeO4)2 single crystals

Abstract K3Na(SeO4)2 single crystal cleaved surfaces were imaged by means of an atomic force microscope in air. The images revealed atomically flat terraces 500 nm wide, with steps, this height being the multiple of the K3Na(SeO4)2 c 2 lattice constant. For the first time, atomic resolution was observed on the KNSe crystal surface in air. Correlation between the images obtained and crystal structure is discussed.

Application of the channel electron multiplier to the unipole mass spectrometer

Abstract The performance of a channel multiplier, type KPE, applied to the ion detection system of the unipole mass spectrometer was tested. It was found that this type of multiplier is fully useful in ion spectrometer systems in the pressure range 10−4–10−12 torr. The amplification characteristic of the ion current vs the pressure of gases reveals a good linearity. The shape of the characteristic indicates that amplification of the electron multiplier for the mixture is dependent only on the amount and kinetic energy of the ions. All three measurement series were taken with the electron multiplier used in the analogue mode of operation.

Energetic dependence of the surface-independent peak in the electron spectrum

Abstract A small peak in the electron energy spectrum at an apparent energy value above the energy of elastically scattered electrons was observed using the cylindrical mirror analyzer (CMA) of our own construction. Calculations based on the parameters of this CMA indicate that this peak can be attributed to some elastically scattered electrons which undergo an additional elastic scatter between the entrance and exit slits of the CMA.