Spectrometer for cluster ion beam induced luminescence

A spectrometer to detect the ultra-weak luminescence originated by the collision of cluster ions on the surfaces of solid materials was constructed. This spectrometer consists of 11 photomultipliers with band-pass interference filters that can detect the luminescence within the wavelength ranging from 300 to 700 nm and of a photomultiplier without filter. The calibration of the detection system was performed using the photons emitted from a strontium aluminate fluorescent tape and from a high temperature tungsten filament. Preliminary measurements show the ability of this spectrometer to detect the cluster ion beam induced luminescence.

Characteristics of acetone cluster ion beam for surface processing and modification

An acetone cluster ion beam was produced by the adiabatic expansion method without using helium as a support gas. The cluster source for the production of ethanol clusters was replaced with that sealed with metal gaskets. The Laval nozzle for the production of ethanol clusters was also replaced with a stainless steel conical nozzle. The cluster size distributions of the acetone cluster ion beams had mean values approximately at 2 × 10(3) molecules and increased with source pressure. The typical beam current density of the acetone cluster ion beam was approximately 0.5 μA/cm(2).

Equipment to detect luminescence induced by cluster ion collision

The possibility to analyze on-line the surface region of solid materials using the cluster ion beam luminescence spectroscopy has been examined. At this aim, the cluster ion beam apparatus for the processing of solid materials was modified. The neutral clusters were ionized by the electron impact ionization to obtain an intense cluster ion beam. The tungsten filament used in this ionization method was replaced with an oxide one to reduce the emission of the background light by decreasing the operating temperature of the filament. To further suppress this light, antireflection materials were used to cover the parts inside the vacuum chamber, such as walls and inner surfaces of the einzel lens. The signal to noise ratio was improved more than one order of magnitude. The emission of photons induced by the irradiation of cluster ion beams was detected.

Characteristics of liquid cluster ion beam for surface treatment

A liquid cluster ion source, which is an ion source for the cluster beams produced with liquid materials, has been developed for the surface treatment of solid materials. The electrodes were designed for increasing the cluster beam intensity by a computer simulation of beam trajectories. The peaks of the cluster size distributions of the water and ethanol cluster ion beams of 3 atm vapor pressure were approximately at 2.4x10(3) and 1.6x10(3) molecules, respectively. The cluster size distributions of ethanol clusters were not sensitive to the variations of the acceleration voltages (V(e)) and currents (I(e)) of the electrons for ionization when the V(e) and I(e) were larger than approximately 200 V and 200 mA, respectively.

Sources of polyatomic ions of organic liquids

We have developed two types of liquid ion sources, one of which was a polyatomic ion source using liquid organic materials with a high-vapor pressure. Liquid materials such as octane and ethanol could be heated up to a maximum temperature of 100 degrees C, and the vapors were introduced into an ion source. They were ionized by an electron bombardment method and extracted from the ionizer. The ion current obtained at an extraction voltage of 2 kV was 230 microA for octane and several fragment ions such as alkyl ions were produced. On the other hand, another type of polyatomic ion source using alkyl naphthalene mixed with ionic liquid such as imidazolium dicyanamide has been developed. Instead of the electron bombardment method, a high-electric field method was used for the ion-emission from a sharp tip, because the vapor pressure of the liquid materials was relatively low. The threshold voltage was approximately 4.5 kV and the ion current of approximately 250 nA was obtained at an extraction voltage of 9.5 kV.