Münster 2011 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 55: Instrumentierung X

HK 55.7: Vortrag

Donnerstag, 24. März 2011, 15:45–16:00, HS2

A novel scheme for suppresing signal cross-talk and ensuring signal integrity in Multi-Strip Counters — •Diego Gonzalez-Diaz — TU, Darmstadt, Germany — GSI, Darmstadt, Germany — Tsinghua University, Beijing, China

Signals induced in typical multi-strip Resistive Plate Chambers (RPCs) can travel up to 40 electrical lengths (40 times the characteristic signal wavelength) over densely packed multi-electrode parallel structures (typically on the number of  30-60 strips). This figure corresponds to a 100ps exponential signal travelling over 2 meters, surrounded by  15 anodes and 15-30 cathodes.

This makes RPCs easily the most extreme scenario for electrical signal transmission of all known detectors in Nuclear and Particle physics. Indeed, when reading out several strips simultaneously, a highly disperssive system arises, stemming fundamentally from modal disperssion and dielectric losses.

So far the topic of signal transmission in multi-strip RPCs has been always addressed on the basis of requiring the system to be ’impedance matched’. We will show that this requirement represents just a minor aspect of the transmission in an RPC structure. Indeed, best transmission is achieved for an impedance matched system only if the capacitive and inductive coupling are accurately balanced. Failing to do so properly results in a cross-talk increase up to a factor of 10 and signal degradation by up to 600 ps. Several simple ways to restore the capacitive-inductive balance are given and verified experimentally, allowing to largely improve the counter behavior with striking ease.