Superconducting RF Injector Fundamental Power Coupler Water Freezing

Superconducting RF Injector Fundamental Power Coupler Water Freezing after Flow has Stopped September 6, 2007 Advanced Energy Systems Inc. TJS 9 -06 -07 Slide # 1

Outline Superconducting RF Injector l Determine rate of ice forming on cold surface – Ice will form behind “pringle” – Radiant heat loss to cavity walls – Pringle cools from RT to 0°C – Heat within pringle – Ice begins to form at rate related to radiant energy loss – RF side of pringle has a much larger area than coolant side l Conservative assumptions – – Heat within pringle only – adjacent parts not included Heat of fusion of water-ice / heat within water not included No thermal resistance in pringle No accounting of conduction from warm end of FPC TJS 9 -06 -07 Slide # 2

Power Coupler With Pringle Superconducting RF Injector Planar-coaxial window Rectangular to coaxial doorknob transition Pringle attached to inner conductor TJS 9 -06 -07 Slide # 3

Pringle Heat Balance Superconducting RF Injector Radiant energy Heat in Pringle Water freezing = 20°C (36°F) TJS 9 -06 -07 Slide # 4

Time for Pringle to Cool and rate of water freezing Superconducting RF Injector Pringle cooling to 32°F _____________ = BTU/hr ________ = BTU/ft . 95 hrs =. 011 ft/hr. 136 in/hr Annular channel is depth =. 097 inches from metal to metal. 097/. 136 =. 72 hrs to fill channel with ice TJS 9 -06 -07 Slide # 5

Conclusions Superconducting RF Injector l Significant amount of time prior to channel filling with ice – > 1. 6 hrs – Heat from other regions of FPC will decrease freezing rate – Local channel depth behind pringle >. 2” l This is a simplified model/analysis – In-depth FE analysis can be done – Time consuming – Include phase change – Results expected to show more time available TJS 9 -06 -07 Slide # 6