Brightness of micronozzle helium source
نویسندگان
چکیده
We have measured the brightness of several helium free jet sources. Five converging nozzles with diameters between 0.6 and 5 m, and three tube nozzles with diameters between 2 and 10 m were studied at stagnation temperatures of 77 and 300 K and at stagnation pressures depending on nozzle size from 350 to 17000 kPa. Smaller nozzles produced higher brightness beams with values approaching 1028 s sr m2 −1. At low-temperature quantum effects on the helium collision cross section significantly decreased the source brightness. We explore the possibility of producing even higher brightness sources with smaller diameter. © 2006 American Institute of Physics. DOI: 10.1063/1.2198813
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