PN B05577AC
1-6
Theory
PIDS Sizing
Description
The PIDS assembly provides the primary size information for particles in the 0.017 µm to 0.4 µm
range. It also enhances the resolution of the particle size distributions up to 0.8 µm. This additional
measurement is needed because it is very difficult to distinguish particles of different sizes by
diffraction patterns alone when the particles are smaller than 0.4 µm in diameter.
The PIDS assembly in the Optical Module uses an incandescent tungsten-halogen lamp and three
sets of vertically and horizontally polarized filters to provide polarized monochromatic light at
three different wavelengths: 450 nm (blue), 600 nm (orange), and 900 nm (near-infrared, invisible).
The light is focused through a slit and is formed into a narrow, slightly diverging beam that is
projected through the PIDS sample cell.
The PIDS assembly measures the pattern of the difference in scattering of vertically and
horizontally polarized light. To obtain as much information as possible about the small particles
measured by the PIDS assembly, it illuminates the particles sequentially with vertically and
horizontally polarized light of the three different wavelengths (colors). The three wavelengths of
light permit three independent measurements of the PIDS effect at different ratios of particle sizes
to light wavelength.
For each of the three wavelengths, the differential scattering pattern (PIDS pattern) is observed at
six detectors centered at a scattering angle of about 90°. In total, the PIDS assembly makes 36
measurements of the light scattered from the sample: scattered light of two polarizations at three
wavelengths and six scattering angles (2 x 3 x 6 = 36). A seventh detector on the opposite side of the
cell from the light source measures the intensity of the unscattered light to determine the amount
of obscuration. The 36 measurements are then reduced to 18: the difference in scattering between
the two polarizations measured at each of the three wavelengths and five scattering angles. These
18 measurements form a pattern that varies sensitively with particle size.
The PIDS measurements are added to the same deconvolution matrix that is used for diffraction
sizing. The relative volume of particles in each size channel is determined by a solution for this
matrix. The analysis is completely integrated, so although two methods are used, a single solution
is obtained.
Содержание LS 13 320
Страница 4: ...PN B05577AC iv Revision History ...
Страница 12: ...PN B05577AC xii Safety Notice Scope of Manual ...
Страница 30: ...PN B05577AC xxx LS 13 320 Introduction System Components ...
Страница 57: ...PN B05577AC 2 21 Installation Making Measurements 2 Figure 2 18 Run Cycle Options Dialog ...
Страница 58: ...PN B05577AC 2 22 Installation Making Measurements Figure 2 19 Reference Background File Selection ...
Страница 59: ...PN B05577AC 3 1 CHAPTER 3 LS 13 320 Software Figure 3 1 LS 13 320 Software ...
Страница 80: ...PN B05577AC 3 22 LS 13 320 Software Preference Options ...
Страница 86: ...PN B05577AC 3 28 LS 13 320 Software Preference Options ...
Страница 105: ...PN B05577AC 3 47 LS 13 320 Software High Security 3 Figure 3 5 User Privileges Dialog High Security ...
Страница 116: ...PN B05577AC 4 10 Regulatory Compliance 21 CFR Part 11 Starting Security Enabled Software ...
Страница 118: ...PN B05577AC 5 2 Data File Menus RunFile Menu 3 Select the file you wish to overlay with the current opened file 4 Open ...
Страница 169: ...PN B05577AC 6 39 Sample Modules Micro Liquid Module 6 Figure 6 27 SOM List Dialog ...
Страница 216: ...PN B05577AC 6 86 Sample Modules Universal Liquid Module ...
Страница 228: ...PN B05577AC B 10 Sample Handling Diluent Selection ...
Страница 238: ...PN B05577AC C 10 Optical Models Statistics ...
Страница 252: ...PN B05577AC Warranty 2 Beckman Coulter Inc Customer End User License Agreement ...
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