Although the theory of Giordmaine and Wang adequately predicts the centerline intensity of a molecular beam from a channel source, it is less successful in describing the angular distribution. This deficiency has been ascribed to a nonzero number density at the tube exit. The end conditions chosen by previous workers lead to angular distributions which fail to satisfy total flow and average cosine restrictions. A method of choosing the parameters of the linear density profile which satisfies these integral constraints is described. The computed angular distributions according to the theories utilizing different end conditions differ very little from each other, but represent a clear improvement over Giordmaine and Wang's angular distribution.
How to cite this article: Kruger V, Redlinger-Grosse K, Walters ST, et al. Development of a motivational interviewing genetic counseling intervention to increase cascade cholesterol screening in families of children with familial hypercholesterolemia.
An apparatus for measuring the leak rates and angular distributions of the molecular flux from multichannel sources was constructed. Four types of beam sources were tested: A single capillary, a crinkly foil stack, an electron-beam milled quartz membrane, and two sources constructed by fiber optics techniques. The leak rates of the sources were compared to the predictions of Knudsen flow. The angular distributions were characterized by a ``peaking factor,'' defined as the ratio of the center-line beam intensity from the source to that from a cosine emitter of the same total flow rate. The measured peaking factors agreed with the theoretical predictions of free molecule flow at low source pressures and approached the limit for isentropic flow at high source pressures.
An experimental system was developed to enable on-11ne mass spectrometrlc analysis of gas phase radlolysls flow systems, and was applied to observation of the oxygen radlolysls system In particular. In this experimental system, energy from a beam of 1-NeV protons is deposited In the oxygen as it flows through a fast-flow reaction tube. A molecular beam source samples the flow gas, and the resulting molecular beam Is then modulated and analyzed with a quadrupole mass spectrometer. Experimentally determined quantities are the concentrations of atomic oxygen, molecular oxygen, and ozone as functions of reaction time, system pressure, and total absorbed dose. Operating parameters were in the following ranges: System pressure: [1.5-4.0] Torr Irradiation time: [0.2-0.3] sec Total energy deposited: [O.S-15] 10 12 heV/cm 3 Dose Rate: [0.2-20] 10 20 heV/gm-sec Observed concentrations of the radlolysls products atomic oxygen and ozone were of the order: Atomic oxygen: [5-40] 10 12 atoms/cm 3 Ozone: [3-20] 10 13 molecules/cm 3 35 character (charge, mass, velocity) of the Ionizing radiation. 35 The value for oxygen is 30.9 eV/lon pair (measured with tritium e), so that the ion g-value 1s: 9 1on ° O00/30.9) = 3.2 ion pa1rs/heV. This g-value applies directly to e", but must be modified to account for the production of both 0 and Q». The latter are assumed to appear with the relative abundance observed In mass spectrometrlc fractionation, (0.83:0.17). The ion g-values are therefore: 9 + • 0.5
An experimental system for on-line mass spectrometric analysis of gas phase radiolysis systems was developed. Oxygen in a fast flow reaction tube was irradiated with 1 MeV protons and subsequently sampled with a molecular beam source~ Analysis of the modulated molecular beam with a quadrupole mass spectrometer provided the concentrations of 0, 0 2 , and 0 3 as functions of reaction time, dose rate, and system pressure. Observed ozone levels were anomalously high compared to the predictions r of existing chemical models, with apparent g-values considerably above theoretical maximum values. Agreement of theory with the data was improved by postulating an excited state of o 2 as a direct precursor to ozone.
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