Update TPC_Bonn.tex

Tracker/TPC_Bonn/TPC_Bonn.tex

@@ -11,10 +11,10 @@ \section{LCTPC Overview}
 additional charge-spreading mechanism was necessary, even for \SI{1}{mm} pads. Such a method was introduced by the Carleton group, using a superposition of an insulator and a resistive cover. This arrangement provides a continuous Resistor-Capacitance (RC) network over the surface which spreads the charge around the avalanche. The induced
 signal is measured, shaped and digitized by the electronics connected to each pad. Note that this technique is applicable also to GEMs and allows pad widths of 2, 3 or more mm.
 
-A higher density of the electronics might be necessary, to mitigate the background at small radius and to improve two-track separation
-where the track density is highest, as well as the fake hit density. This can be done by switching to the \SI{65}{nm} technology for the
+On the electronics side, a higher density readout might be necessary, to mitigate the background at small radius and to improve two-track separation where the track density is highest, as well as the fake hit density. This can be done by switching to the \SI{65}{nm} technology for the
 chip design. Though the present consumption is rather moderate (\SI{15}{mW/channel}), a suitable power-pulsing operation should be adapted.
 Early estimates show that such a system can be designed, but requires a careful balance between power saving and increased complexity.
+
 At the beginning of the years 2000, several small prototypes were built in Aachen, Amsterdam, Saclay-Orsay with a Berkeley electronics, DESY, Munich, Karlsruhe, Carleton, Victoria, Saga, KEK, Tsinghua, to study various aspects of the GEM and Micromegas technology. Ion feed-back was studied, resolution was measured in various prototypes, and the possible gases were studied. The fundamental proof was made that a TPC with MPGD readout can be operated stably, and can reach intrinsically the anticipated resolutions.
 
 Then, in 2004, part of the nascent collaboration gathered around a \SI{5}{GeV} pion beam and cosmic-ray tests at KEK. The detector was immersed in a \SI{1}{T} magnetic field from a permanent-current superconducting magnet. The \SI{25}{cm} drift field cage was designed in Munich and electronics was recuperated from ALEPH. Several endplates were adapted to this cage with wires, Micromegas (without resistive foil) and GEM technologies. In 2006 the Carleton \SI{16}{cm} drift length prototype with a Micromegas resistive foil took data simultaneously with the Munich prototype.