Source slit

SOURCE SLIT (FIXED) FOCUS (BEAM CENTRE) SOURCE EI/CI... 

Figure 3.1 (a) Schematic diagram (not to scale) of Young s double-slit experiment. The narrow slits acts as wave sources. Slits S and S2 behave as coherent sources that produce an interference pattern on screen C. (b) The fringe pattern formed on screen C could look like this. (Reproduced with permission from R. A. Serway Physics for Scientists and Engineers with Modern Physics, 3rd ed, 1990, Saunders, Figure 37.1.)... 

Source slit Multiplier slit Monitor exposure Multiplier and amplifier gains Electrodes, vibrated... 

The reduction in energy spread means that double focusing is unnecessary. Micromass achieves excellent peak shape and reproducibility with single (directional) focusing. So the lens system is virtually identical to that used in TIMS, accelerating the ions through a stack that starts with an extraction plate at —900 V and ends with a source slit at —8 kV. 

Figure 7.15 Two slit experiment demonstrating the interference of monochromatic light. Concentric curves (cylinders) represent locations of maximum intensity of light waves propagating from the slit sources. Dimensions have been accentuated for clarity generally the slits are 0.1 mm wide and 1 mm apart, the distance from the source slit to the double slit screen is 0.6 m and from the double slit to the screen, 3 m [16). As the double slits are brought closer together, more interference fringes will appear on the screen.

An important component in any instrument is a set of one or more mechanical slits (or holes) that limit the spatial width of radiation (i) The "source slit" limits the width of the radiation source seen by the sample (ii) the "detector slit" limits the width of the radiation emitted by the sample and sent to the detector. On the one hand, the narrower the slit (or hole), the better the resolution, but on the other hand, the narrower the slit or hole, the weaker the signal seen by the detector. The slits also control the effective bandwidth of the instrument Very narrow slits yield the smallest bandwidth and the best energy or wavelength resolution, but this comes at a price of a weaker signal. 

When a curved reflecting crystal (Fig. 15-5) is used, the line width depends mainly on the width of the source slit 5 and the precision with which the crystal is ground and bent. The line width is normally about the same as that obtained with a flat crystal, namely, about 0.5°. 

In Fig. 3 the apparatus is shown with which Stolte (1972) has performed measurements of this type NO molecules were selected with the help of electrostatic sixpole fields, in accordance with their linear Stark effect in strong fields. The source slit of 0 05 mm width has an image formed by the selected NO molecules in the plane of the detector slit which has an experimental width of 1-4 mm f.w.h.m. this width includes all disturbing effects like the magnification factor (about 18), the imperfect linear Stark effect of the NO molecules in the selected state, the finite width of the transmission of the velocity selector (Av/v = 7% f.w.h.m.) in combination with the chromatic lens errors and the directional dependence of the maximum transmitted velocity of the velocity selector. The j = nij = Q = 3/2 state was selected where 1 is the projection of the electronic angular momentum on the molecular axis. The hyperfine structure of NO influences the situation only slightly. 

A monochromator is usually used as a wavelength selector. Monochromators are composed of a dispersing medium to separate the wavelengths of the polychromatic radiation from the source, slits to select the narrow band of wavelengths of interest and lenses or mirrors to focus the chosen radiation. 

Imaging system it ordinarily contains little reflector, cutter point, filter, special lens and imaging medium. The cutter point includes black-white and color edge and is the key component of schlieren apparatus. It is parallel to the source slit and is located in the focal plane of reflector. When there is no disturbance in the flow field, if the knife cut off part of the image of the source, light intensity on photographic plane will weaken uniformly. Black and white edge has steel sheet with... 

Fig. 30. Schematic diagram of ICP 1) = HF generator 2) = plasma 10,000 K 3) = source slit = refractor plate 5) = grating 6) = atomizer 7) = sample 8) = amplifier 9) = exit slit 10) = photomultiplier 11) = argon 12) = simultaneous measurement system 13) = computer U) = terminal 13) = printer...

Fig. 39 c. Magnetic sector mass spectrometer 1) = Ion source 2) = FFR 1 collision cell 3) = Source slit = Magnetic sector 3) = Focusing element 6) = Intermediate slit 7) = FFR 2 collision cell 8) = Focusing element 9) = Electric sector 10) = Collector slit 11) = Conversion dynode 12) = Secondary electron multiplyer (SEM)... 

The ion beam width (w ) at the image position is related to the ion beam width defined by the source slit (t g), the image lateral magnification (M) and the sum of the imaging aberration coefficients (a) by ... 

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