Improvement of a Simultaneous Detection System of Several Kinds of Particles Desorbed from a Surface in the Same Instant

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 10650027
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 表面界面物性
• Research Institution: Kanagawa Institute of Technology
• Principal Investigator: USAMI Seiji Engineering, Professor, 工学部, 教授 (40017877)
• Co-Investigator(Kenkyū-buntansha): BANDAI Toshio Engineering, Associate Professor, 工学部, 助教授 (10121229)
• Project Period (FY): 1998 – 1999
• Keywords: SIMULTANEOUS DETECTION OF IONS / 90° ION-DEFIECTOR MAGNET / 90°偏向磁石

Research Abstract

In this research, it was attempted to detect in the manner of mass separation simultaneously several kinds of particles desorbed from a surface for a study on surface-particle interaction. A mass analyzer that resolves different mass particles with a compact permanent magnet was constructed. A permanent magnet formed in a modification of a sector of an open angle 225°(=180°+45°) drives ionized particles in a semi-circular orbit, then when the particles leave the edge of the magnet every kinds of charged particles moves in parallel along a straight line perpendicular to the incident direction which is parallel to the another edge of the sector. After mass separation, all of ions move in parallel with a different distant length from the entrance point as a function of mass number.
For instance, an ion enters into the magnetic field along the horizontal direction, then it runs towards the vertical direction with a distant length proportional to the root of mass number. Therefore, the parti cles distribute on a straight line and take different positions depending on the mass number.
When number of detectors are located along the above line, it is possible to obtain signals of different particles in a separated way at the same time.
Here three secondary electron multiplers(EMS-6081B, Murata Co.) were mounted to catch ions running in a straight way to them. The output signals of detectors were observed on a 4-channel sampling oscilloscope(TDS 3034, Tektronix). Signals appear on either of channels by adjusting the ion acceleration voltage in the ion chamber.
The average density of magnetic flux in the center of the magnetic pole gap was 146 gauss and the detectors were located at 50,75 and 100 mm distant from the entrance. On this condition, the signals were observed with definite values of acceleration voltages ; in the one case, single signal on a single channel or in another case, signals on all channels. Signals were attributed to be either of hydrogen atom or of hydrogen molecule, or of helium.