10 Signal Processing for Particle Detectors
479
In particle physics, recently developed cold monolithic electronics has enabled
scaling up of liquid argon time projection chambers to a very large size, required for
studies of neutrino oscillations and nucleon decay. Such detectors, which originated
with the ICARUS project [58], in the size range of up to few hundred tons, will have
to be built in the range, unthinkable so far, of tens of kilotons. The number of sense
electrodes (wires) and the readout amplifiers will be in the range of ~5·10 5 to 3·10 6 ,
assuming a reasonable electron drift length in the time projection chamber (TPC)
and the sense wire length. Readout by monolithic amplifiers (with multiplexing)
placed at wire electrode frames, results in a significantly lower noise (due to a
lower capacitance) than with long cables bringing the signals from each sense
wire to the outside of the cryostat, and in a much lower number of cables and
feedthroughs. This also allows the design of the cryostat to be freed from the signal
cable constraints. The “cold electronics” in this case will have a beneficial impact
on both the engineering and the physics, i.e., a higher signal-to-noise ratio allowing
better background rejection and a higher precision in the track measurement and
reconstruction increasing the sensitivity for detection of interesting phenomena [59,
60]. Such a detector, on a smaller scale (~75 tons of liquid argon with ~8300 sense
wires and electronic channels immersed in liquid argon), has been built and operated
for two years. Uniformity and stability of the gain and noise has been demonstrated
[61].
10.9.3 Beyond the Moore’s Law
As the MOSFET technology advances further into the nanoscale domain (gate
widths down to 5–10 nm), Moore’s law, as defined for CMOS transistors, is running
up against the physical, technical and economical limitations, and eventually
against the granularity of matter (silicon lattice constant ~0.54 nm). Physical
phenomena associated with small dimensions, such as quantum mechanical effects
and fluctuations in the decreasing number of dopants, take place. These effects cause
leakage currents (incomplete drain current turn-off and gate tunnelling currents) and
dispersion in device parameters (threshold voltage). Associated with the necessity
for tighter control of all device and fabrication process parameters are increasing
costs.
Recent research toward smaller, faster and lower power devices has been concentrated on “beyond CMOS” devices [62–64]. As with the CMOS, new developments
are being driven by the needs for high density-high speed digital and computer
circuits. Besides the physical variables considered as “computational variables”
familiar in CMOS (current, voltage, charge), other variables are being considered
(electric dipole, magnetic dipole, orbital state). Among possible device concepts
being explored are:
• Tunneling FET
• Graphene nanoribbon FET
479
In particle physics, recently developed cold monolithic electronics has enabled
scaling up of liquid argon time projection chambers to a very large size, required for
studies of neutrino oscillations and nucleon decay. Such detectors, which originated
with the ICARUS project [58], in the size range of up to few hundred tons, will have
to be built in the range, unthinkable so far, of tens of kilotons. The number of sense
electrodes (wires) and the readout amplifiers will be in the range of ~5·10 5 to 3·10 6 ,
assuming a reasonable electron drift length in the time projection chamber (TPC)
and the sense wire length. Readout by monolithic amplifiers (with multiplexing)
placed at wire electrode frames, results in a significantly lower noise (due to a
lower capacitance) than with long cables bringing the signals from each sense
wire to the outside of the cryostat, and in a much lower number of cables and
feedthroughs. This also allows the design of the cryostat to be freed from the signal
cable constraints. The “cold electronics” in this case will have a beneficial impact
on both the engineering and the physics, i.e., a higher signal-to-noise ratio allowing
better background rejection and a higher precision in the track measurement and
reconstruction increasing the sensitivity for detection of interesting phenomena [59,
60]. Such a detector, on a smaller scale (~75 tons of liquid argon with ~8300 sense
wires and electronic channels immersed in liquid argon), has been built and operated
for two years. Uniformity and stability of the gain and noise has been demonstrated
[61].
10.9.3 Beyond the Moore’s Law
As the MOSFET technology advances further into the nanoscale domain (gate
widths down to 5–10 nm), Moore’s law, as defined for CMOS transistors, is running
up against the physical, technical and economical limitations, and eventually
against the granularity of matter (silicon lattice constant ~0.54 nm). Physical
phenomena associated with small dimensions, such as quantum mechanical effects
and fluctuations in the decreasing number of dopants, take place. These effects cause
leakage currents (incomplete drain current turn-off and gate tunnelling currents) and
dispersion in device parameters (threshold voltage). Associated with the necessity
for tighter control of all device and fabrication process parameters are increasing
costs.
Recent research toward smaller, faster and lower power devices has been concentrated on “beyond CMOS” devices [62–64]. As with the CMOS, new developments
are being driven by the needs for high density-high speed digital and computer
circuits. Besides the physical variables considered as “computational variables”
familiar in CMOS (current, voltage, charge), other variables are being considered
(electric dipole, magnetic dipole, orbital state). Among possible device concepts
being explored are:
• Tunneling FET
• Graphene nanoribbon FET