Dielectric Donut Final Design B. Freemire IIT HPRF/HCC Design Meeting August 27, 2014
Quotes Accuratus – No ● Morgan – Largest parts they ● make are 8” in diameter, can get one from sister companies; solid disk $1,200 - $1,500 Coorstek – 1 piece for $1,800, 2 pieces for $2,500, 10 week lead time ● I received a sample piece today (99.5%) – Offer 85, 90, 94, 96, 98.5, 99.5, 99.8 & 99.9% alumina – 8/13/14 B. Freemire - HPRF/RF Breakdown 2
CoorsTek AD-995 ● Specs: – ε r = 9.81 ( σ = 0.01) – tan δ = 7x10 -5 ( σ = 5x10 -6 ) – Above measured at 5 GHz – Dielectric strength = 8.7 MV/m ● This dielectric constant requires changing Frank's donut's dimensions 8/13/14 B. Freemire - HPRF/RF Breakdown 3
Donut Simulations Gaskets Teflon Alumina 100 atm H 2 ε r = 9.0, f =799.31 MHz ε r = 9.81, f = 794.55 MHz 8/13/14 B. Freemire - HPRF/RF Breakdown 4
Donut Criteria Dimensions of ring will have to be tweaked slightly ● I will aim for a “high” frequency ● Easier to bring down frequency of cavity – Teflon spacers are arbitrary ● Making them smaller is one way to bring up frequency – Variation in ε r effect on frequency to be investigated ● Frank's thermal calculations show heating not an issue ● 8/13/14 B. Freemire - HPRF/RF Breakdown 5
“Easier” Geometry I've been looking at an insert geometry that would be simpler to machine ● Approaching optimal dimensions ● 20 atm H 2 100 atm H 2 f = 806.59 MHz f = 800.65 MHz 8/13/14 B. Freemire - HPRF/RF Breakdown 6
Plan ● Take measurements of sample provided by Coorstek this week ● Finalize dimensions of approved geometry ● Order 2-3 pieces of varying purity next week 8/13/14 B. Freemire - HPRF/RF Breakdown 7
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