A high-energy particle-beam transmission window for use at atmospheric pressure

Summary form only given. Although it is possible to transmit a high-power particle beam pulse through a transmission window, the integrated energy remains low because of energy deposition in the transmission window, which heats it and reduces its mechanical strength. A theoretical analysis of heat transport for a transmission window exposed to atmospheric pressure suggests that a straightforward cooling technique employing direct fluid flow within the transmission window will lead to a one to three order of magnitude increase in beam flux, thereby circumventing the limitation of low heat dissipation. Estimates of the convective heat-transfer coefficient for fully developed turbulent fluid flow indicate that a significant increase in beam flux can be realized compared with that of a traditional transmission window membrane. Mechanical and thermal constraints are discussed, as well as the hydraulic system necessary to achieve appropriate fluid flow. Experimental heat-transfer coefficients for turbulent flow in capillary tubing indicate that it would be possible to fabricate a foil window capable of supporting continuous heat dissipation of approximately 1 kW/cm/sup 2/ across a 2-cm diameter window.