Laser ion source

Glow discharge source (GDMS) Laser ion source (LIMS) Secondary ion source (SIMS) Sputtered neutral source (SNMS) Thermal ionization source (TIMS) Inductively coupled plasma ion source (ICP-MS)... 

The development of laser ionization mass spectrometry was started by Honig and Woolston in 196359 with studies of laser beam sohd surface interaction and ion formation processes. Due to the pulse character of laser-induced ions, ToF analyzers were coupled to laser ion sources in the seventies and produced commercially as LAMMA-500 and later LAMMA-1000 and 2000 (Leybold-Heraeus, Cologne, Germany). 

The ion source is an essential component of all mass spectrometers where the ionization of a gaseous, liquid or solid sample takes place. In inorganic mass spectrometry, several ion sources, based on different evaporation and ionization processes, such as spark ion source, glow discharge ion source, laser ion source (non-resonant and resonant), secondary ion source, sputtered neutral ion source and inductively coupled plasma ion source, have been employed for a multitude of quite different application fields (see Chapter 9). 

To make the instrument more versatile, some spark source units have been redesigned in the past to make them interchangeable with other types of ion sources (e.g., laser ion source). The insertion of a laser ion source instead of a spark ion source allows the direct analysis of insulators without any treatment, as described by Dietze.74 75 79... 

Figure 2.19 Experimental arrangement of laser ion source (H. ]. Dietze, ]. S. Becker and Z. Fresenius, Anal. Chem. 32 i, 490 (1985). Reproduced by permission of Springer Science and Business Media.)...

It is characteristic of such a laser ion source that the experimental conditions for LIMS can be optimized with respect to a stoichiometric evaporation and effective ionization of solid sample material by varying the laser power density as demonstrated in Figure 2.20. Under certain experimental conditions fractionation effects can be avoided. Stoichiometric laser evaporation and ionization of analyzed material is found at a laser power density between 109Wcm 2 and 1010Wcm-2. In this laser power density range, the relative sensitivity coefficients of the chemical elements (RSC = measured element concentration/true element concentration) are nearly one for all the... 

A high vacuum laser ion source is combined with a dynamic (ToF-MS) or static mass spectrometer (Mattauch-Herzog instrument) for the separation of the ion beams formed and used in LIMS for multi-element major, minor and trace analysis of compact solid samples (bulk analysis).74... 

Laser ion source in laser plasma by e impact Wa 1°4-nx1°5K ne 1 016-1 O20 crrr3 M+ high < 1 4 Pa double-focusing SFMS (Mattauch-Herzog) traces, high-purity ceramics... 

Figure 5.24 Experimental setup of a double-focusing sector field mass spectrometer with Mattauch-Herzog geometry with interchangeable spark and laser ion source. (/. 5. Becker and H. /. Dietze, Int. /. Mass Spectrom. Ion Proc. 197, 1 (2000). Reproduced by permission of Elsevier.)...

The magnet of an on-line mass separator will generally assure the selectivity in respect to different isotopes. Hence, the isobaric selectivity of laser ion sources is of primary interest, although isotopic selectivity might also be achieved by RIS using the HFS and IS, which differ from isotope to isotope. 

Fig. 4 Right Principle of resonance ionization spectroscopy. Three tunable pulsed Dye lasers are used to stepwize excite and ionize the atom. The effective cross-sections are indicated for the different transitions in cm2. Left Layout of a laser ion source for on-line mass separators.

Observation of fluorescence with pulsed ion beam 10 duty cycle of laser ion source rare earth in preparation [KLU85]... 

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