Ultrafast Chemical Separations (1993) / Chapter Skim
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5. Delivery Systems for Continuous Techniques
5. Delivery Systems for Continuous Techniques
Pages 49-58
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From page 49... ...
Gasjet systems have been routinely used in particle accelerators to transport reaction products from the production site to a detector position for counting; in some cases, the products are delivered to a chemical separation system. The gasket system has been adapted for continuous delivery of fission products from a target chamber to a separation system where chemical or mass separation can be carried out.
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From page 50... ...
The use of gas to transport nuclear reaction products produced in accelerators increased in He following decades. In the 1960s and early 1970s, a number of research groups expenmented with helium gasket systems for thermalizing and carrying reaction products from targets in accelerators.
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From page 51... ...
Wiesehahn and coworkers rwie731 invest extensively the role of clusters In the transport of radioactivity In a gasket system. They showed ~ impurities In ethylene play only a minor role In carrying radioactivity; they also showed that a neutron flux of 10§ n cm~2 so is unlikely to produce sufficient cluster density for transporting fission products.
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From page 52... ...
The Sinclair-LaMer generator produced aerosols of nearly uniform size that transported efficiently Croup long capillary tubes; this technique of production of aerosols gave the highest overall efficiency. The loule-Thomson effect produced a large number of particles of small size that were lost most readily during transport; the overall efficiency was smallest for transport using aerosols generated using this technique.
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From page 53... ...
measured the transport time as a function of flow rate of ethylene by injecting a pulse of helium into the carrier gas and using a helium-leak detector to signal the arrival of helium at the collection chamber. They observed a smooth decrease in transport time with increasing flow rate of the carrier gas.
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From page 54... ...
Even though the values reported are applicable to the specific system used, the information gives a general clue to the nature of microscopic transfer of reaction products. As mentioned in previous paragraphs, the transport time decreased with increase of flow rate and increase of target-chamber pressure.
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From page 55... ...
A multiscaling spectrum of p-ray counts of transported fission products for the measurements of ~ sweepout and transit times through an O ~ o Il.S-m capillary with I.O-mm inner diameter at a helium pressure of I.1 atm. The volume of the target chamber is 30 cm3.
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From page 56... ...
The outlet from the target chamber was connected to a two-way, electrically operated valve. The fission products carried by ethylene clusters passed Trough the valve and were retained by a quartz-woo} trap In front of a detector.
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From page 57... ...
. In both experiments, the target chamber pressure was 25 psi and the gas flow was 2.6 L/min (at ~ atm and 22°C)
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From page 58... ...
The fission products from the target chamber were transported through 7 m of capillary tubing. A transport time of ~ s from the target chamber to the end of the capillary was observed at a flow rate of 20 cm3/s [Tra751.
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