Magnetic sector mass selector

Although magnetic sector is an old technique for separating ions, it is still favored as a method for size selection in supported cluster systems [105-108], Thompson developed this technique and used it for chemical analysis in the 1910s. The physics behind this technique is attributed to the Lorentz force, which accelerates a point charge moving in a magnetic field but perpendicularly curves the particle s motion  

Substituting for v provides a relation between the mass-to-charge ratio and the magnetic field and kinetic energy of ions at the entrance of the magnetic sector  

From the aforementioned equation, one can see that there are two modes of operation for the magnetic sector mass spectrometer. One method holds the magnetic field constant and scans the mass by varying the potential applied to the ion optics the other method varies the magnetic field to control the selected mass while keeping the kinetic energy of the ions constant. 

The mass resolution for a magnetic sector mass selector is high, especially when combined with an electric sector in the so-called double-focusing mode. The disadvantage of this type of mass selector is that the system becomes rather complicated if 

---

Laser Ablation Cluster Source with a Magnetic Sector Mass Selector at the University of California, Santa Barbara... 

Buratto and coworkers use a laser ablation source to produce clusters and magnetic sector mass selector in their deposition instrument (see Fig. 3.13). The cluster intensity varies with materials and desired size for example, a current of about... 

FIGURE 7 Tandem mass separator. Sample ions enter mass selector 1, where the parent ions are separated. The selected ions next enter the collision chamber, where they collide with gas molecules to form the daughter ions, which are finally separated in the mass selector 2 and expelled for detection. Either magnetic sector or quadrupole mass analyzers or both types mixed can make up a tandem mass spectrometer. A single ion trap can also function as a tandem mass spectrometer performing the same processes as described above in the same location but in consecutive steps. 

---