[en] Short communication

[en] The description is given of a transit time mass spectrometer comprising an analyser chamber in which a pulse ion source, an ion detector and an ion reflexion system are placed along the same optical axis of the ions. The ion detector and the ion reflexion system are located on two opposite sides in relation to the pulse ion source, the latter being a source of which all the electrodes are transparent to the ions

[en] In this paper electronic circuits are described for the time measuring channel of a mass spectrometer designed for space applications. In this context the principal aspects of space electronics are described, such as low power consumption, low weight and low volume as well as high reliability. (orig.)

[en] Abstract only

No abstract available

No abstract available

[en] We have modeled, designed, built, and tested a novel reflectron time-of-flight (TOF) analyzer, which is capable of performing surface analysis using both secondary ion mass spectroscopy (SIMS) and mass spectroscopy of recoiled ions (MSRI). All elements (including H and He) can be identified, with isotopic resolution, using both MSRI and SIMS. For ions of a given mass, the higher energy ions penetrate further into the reflectron before being turned around while the lower energy ions do not penetrate as deeply. By properly adjusting both the experimental geometry and the reflectron voltages, all ions of a given mass arrive at the detector simultaneously resulting in enhanced mass resolution compared with simple TOF detection. SIM spectra are complicated by molecular fragments in addition to elemental ions. In MSRI only elemental ions are detected. As a result, data analysis in MSRI is less complicated than in SIMS. Being able to use a single analyzer to selectively obtain SIMS or MSRI data provides complementary surface information. MSRI has a number of unique capabilities for surface studies. In situ, real-time surface analysis can be performed during film growth at pressures of ∼2.5 mTorr at the substrate by differentially pumping both the ion source and the reflectron analyzer region. It has been demonstrated that the ratio of the positive to negative ion yield is phase specific; for example, one can clearly distinguish the different forms of carbon (diamond versus graphite versus amorphous carbon) during film growth. MSRI analysis of poorly conducting surfaces is possible. copyright 1999 American Vacuum Society

[en] Combination of Three Dimensional Quadrupole Ion Trap and Time Of Flight Mass Spectrometer is very interesting because they both rely on time though in a different manner. The 3DQIT can accumulate many ions of which the desired ions can be selected and kept for a very long period of time. Ions can subsequently be extracted in a short burst from the 3DQIT to be sent in a TOFMS. This process can be eased if the trapped ions are cooled by collisions with gas molecules inside the trap. We will discuss from the basic principles of physics what are the best conditions leading the maximum number of usable ions to penetrate in the TOFMS while keeping the resolving power at an acceptable level

[en] The ORNL Atom Probe is a microanalytical tool for studies in materials science. The instrument is a combination of a customized version of the vacuum system of the VG FIM-100 atom probe, an ORNL-designed microcomputer-controlled digital timing system, and a double curved CEMA Imaging Atom Probe detector. The atom probe combines four instruments into one - namely a field ion microscope, an energy compensated time-of-flight mass spectrometer, an imaging atom probe, and a pulsed laser atom probe

[en] A method for electrically adjusting an ion beam in an MSKh-4 mass-spectrometer has been developed. The adjusting system consists of two deflecting plates fastened to the frame of the ion source. By adjusting the potential difference at the plates in the range 0-150 v, one can increase the intensity of the mass-spectrum by a factor of 3 to 5