16 Integration of Detectors into a Large Experiment: Examples from ATLAS. . .
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general enough nature that they might well apply to any complex high-tech project
of this size. It is therefore hard to classify them in a clear logical order, and this
review has attempted to rank them from the general and common to the specific and
unique to the LHC.
16.2.3.1 Time-Scales, Project Phases and Schedule Delays
If there has been one lesson learned from the days in the early 1990s when ATLAS
and CMS came into being as detector concepts, it is certainly that the research and
development phase of projects of this complexity are impossible to plan with real
certainty about the time-scales involved. Modern tools for project management are
of little help here because the vagaries of the initial phase do not generally obey the
simple laws of project schedules and charts. These can be a posteriori explained of
course:
• the research and development phase for new high-tech detector elements, such
as radiation-hard silicon sensors and micro-electronics, crystals grown from
a new material, large-scale electrodes for operation at high voltage in liquid
Argon, etc., will always be a phase to which one has to allocate as much time
as feasible within the overall project schedule constraints. The justification for
this is basically that the potential rewards are enormous, as was exemplified
by the late but striking success of the deep sub-micron micro-electronics chips
pioneered by CMS and now used throughout all LHC experiments, and by
the late but successful operation of CMS PbWO 4 crystals with their avalanche
photodiode readout and associated electronics. Making the appropriate research
and development choices at the right time will however always remain a
challenge for any new project of this scope and complexity.
• less known to many colleagues in our community is the phase during which
the components for producing complex detector modules are launched for
manufacturing in industry. This phase can indeed be planned correctly if the
required physicist/engineering experience is available, if the funding allows for
multiple suppliers to mitigate potential risks, and if the physicists agree quickly
to moderate their usually very demanding specifications to adapt them to the
actual capabilities of industry.
Experience has shown however that success was far from guaranteed in this
phase, with causes for delays or outright initial failures ranging from being forced
to award contracts to the lowest bidder, to incomplete technical specifications, to
handling and packaging issues during manufacturing, particularly for polyimidebased products, of which there are many thousands of m 2 in both experiments.
This material shows up under various forms (especially in flexible printed circuit
boards for various applications) and is a basic insulating material with excellent
electrical and mechanical properties, with very high tolerance to radiation, but
unfortunately also with a high propensity to absorb moisture and thereby lead to
unexpected changes in even the course of a well-defined manufacturing process.
707
general enough nature that they might well apply to any complex high-tech project
of this size. It is therefore hard to classify them in a clear logical order, and this
review has attempted to rank them from the general and common to the specific and
unique to the LHC.
16.2.3.1 Time-Scales, Project Phases and Schedule Delays
If there has been one lesson learned from the days in the early 1990s when ATLAS
and CMS came into being as detector concepts, it is certainly that the research and
development phase of projects of this complexity are impossible to plan with real
certainty about the time-scales involved. Modern tools for project management are
of little help here because the vagaries of the initial phase do not generally obey the
simple laws of project schedules and charts. These can be a posteriori explained of
course:
• the research and development phase for new high-tech detector elements, such
as radiation-hard silicon sensors and micro-electronics, crystals grown from
a new material, large-scale electrodes for operation at high voltage in liquid
Argon, etc., will always be a phase to which one has to allocate as much time
as feasible within the overall project schedule constraints. The justification for
this is basically that the potential rewards are enormous, as was exemplified
by the late but striking success of the deep sub-micron micro-electronics chips
pioneered by CMS and now used throughout all LHC experiments, and by
the late but successful operation of CMS PbWO 4 crystals with their avalanche
photodiode readout and associated electronics. Making the appropriate research
and development choices at the right time will however always remain a
challenge for any new project of this scope and complexity.
• less known to many colleagues in our community is the phase during which
the components for producing complex detector modules are launched for
manufacturing in industry. This phase can indeed be planned correctly if the
required physicist/engineering experience is available, if the funding allows for
multiple suppliers to mitigate potential risks, and if the physicists agree quickly
to moderate their usually very demanding specifications to adapt them to the
actual capabilities of industry.
Experience has shown however that success was far from guaranteed in this
phase, with causes for delays or outright initial failures ranging from being forced
to award contracts to the lowest bidder, to incomplete technical specifications, to
handling and packaging issues during manufacturing, particularly for polyimidebased products, of which there are many thousands of m 2 in both experiments.
This material shows up under various forms (especially in flexible printed circuit
boards for various applications) and is a basic insulating material with excellent
electrical and mechanical properties, with very high tolerance to radiation, but
unfortunately also with a high propensity to absorb moisture and thereby lead to
unexpected changes in even the course of a well-defined manufacturing process.