Bandwidths of Transmission Line Anodes Jean-Francois GENAT LPNHE Paris LAPPD Workshop, Chicago, April 26th 2011

LAPPD 8” x 8” Micro-channel Plates Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011 Micro-strip Lines Parameters: - Strip width W - Inter-strip distance d - Metal conductivity  - Dielectric constant  r

Timing resolution (Stefan Ritt) Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011 Since and where whith

MCP signals Segmented anodes, Burle-Photonis Glass + ALD MCPs (from Matt Wetstein, ANL) Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011 Rise-time 66ps abw=5.3 GHz

MCP ‘nominal’ signals spectra 25 microns at 2 kV, 50 Photo-electrons 10 microns at 2.5 kV “ Data taken at Argonne (Ed May’s laser test stand) Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011

‘Nominal’ Timing resolution (model) Assume: SN = 50 f s = 10 GS/s abw = 1 GHz T r =.35/abw = 350ps T s = 1/ f s = 100ps Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011

Skin effect Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th No need to have more than 10  m metal (~5 x  at 1 GHz) Resistivity and Skin Depth at 1 GHz Al 2.8 n .m 2.4  m Au Cu Ag

Test plate Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011

Measured Microstrip Bandwidth Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th dB bandwidth is 3.77GHz for a 8” trace This measured bandwidth agrees with the simulations using HFSS (Mentor-Graphics)

Transmission Lines Bandwidths Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011 Two main factors for losses: - Resistance of the metal traces vs 50  : metal conductivity, skin effect, as - Dielectric losses: complex dielectric constant The Borofloat glass loss tangent is unknown at 10 GHz, but we measured it at 3.77 GHz for a 8 ’’ long microstrip line. The loss tangent at 10 GHz can be deduced from this measurement to Copper 10 GHz A 5m copper line has a metal induced 3dB bandwidth of 10 GHz

Examples with Quartz and Alumina Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011 Dielectric losses Example: f=10GHz, tan(  )= , C=60pF/m, Z 0 =50  Quartz Alumina The strip length for a 3dB bandwidth is: At 10 GHz: Quartz: 58m Alumina: 35m

Thanks !

Borofloat 33 properties Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011

Dielectric constants Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011 Quartz Beryllia Fused Quartz Alumina 96% Alumina 99.5% GHz Glass (Borofloat) MHz GHz RF ceramic Dielectric constant Loss 1 GHz

Example: FR4 Microstrip line Losses Jean-Francois Genat, LAPPD Workshop, Chicago, April 28 th 2011 Dielectric FR4 losses dominate > 200 MHz Conductor losses contribute > 5 GHz Andrew Byers (Tektronix)