16 Integration of Detectors into a Large Experiment: Examples from ATLAS. . .
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responsibilities were not allowed to operate for too long in a stand-alone mode
without synchronising with and reporting back to Technical Co-ordination, the
management of the experiments and the collaboration at large. The risks involved
in letting things go astray too much are simply unacceptable for projects of this
complexity and size.
• As stated above, one weakness perhaps of the multiple dimensions under
which ATLAS and CMS are viewed is that the funding agencies have often
conducted their own necessary review processes in a way largely decoupled
from the review process operated by the management of the experiments. This
weakness stems from the lack of central control of expenditures because of the
distributed funding and spending responsibilities. This can obviously lead to
inefficiencies in the actual execution of the project and, worse, sometimes to
conflicting messages given to the institutes concerning priorities, since those of a
given funding agency may not always coincide with those of the experiment.
The common funds necessary to the construction of significant components
of the experiments, such as magnets, infrastructure, shielding, cryostats, etc.,
are a prominent example which comes to mind, when assessing which of the
components of the experiments had the most difficulty in dealing with the multithreaded environment, in which the detector construction has been achieved.
Finally, it is in the very recent phase of assembly, installation and commissioning
of the ATLAS and CMS detectors that the enormous efforts and contribution from
the Technical Co-ordination teams have been most visible: they have had to organise
the vast teams of sub-contractors and specialised personnel from the collaborating
institutes and they have had to deal with the daily burden of making sure all the
tasks were executed as smoothly as possible with safety as one of the paramount
requirements.
16.3 Inner Tracking System
16.3.1 Introduction
The ATLAS tracker is designed to provide hermetic and robust pattern recognition,
excellent momentum resolution and both primary and secondary vertex measurements [17] for charged tracks above a given p T threshold (nominally 0.5 GeV, but
as low as 0.1 GeV in some ongoing studies of initial measurements with minimumbias events) and within the pseudorapidity range |η| < 2.5. It also provides electron
identification over |η| < 2.0 and a wide range of energies (between 0.5 and
150 GeV). It is contained within a cylindrical envelope of length ±3512 mm and of
radius 1150 mm, within the solenoidal magnetic field of 2 T. Figures 16.8 and 16.9
show the sensors and structural elements traversed by 10 GeV tracks in respectively
the barrel and end-cap regions.
715
responsibilities were not allowed to operate for too long in a stand-alone mode
without synchronising with and reporting back to Technical Co-ordination, the
management of the experiments and the collaboration at large. The risks involved
in letting things go astray too much are simply unacceptable for projects of this
complexity and size.
• As stated above, one weakness perhaps of the multiple dimensions under
which ATLAS and CMS are viewed is that the funding agencies have often
conducted their own necessary review processes in a way largely decoupled
from the review process operated by the management of the experiments. This
weakness stems from the lack of central control of expenditures because of the
distributed funding and spending responsibilities. This can obviously lead to
inefficiencies in the actual execution of the project and, worse, sometimes to
conflicting messages given to the institutes concerning priorities, since those of a
given funding agency may not always coincide with those of the experiment.
The common funds necessary to the construction of significant components
of the experiments, such as magnets, infrastructure, shielding, cryostats, etc.,
are a prominent example which comes to mind, when assessing which of the
components of the experiments had the most difficulty in dealing with the multithreaded environment, in which the detector construction has been achieved.
Finally, it is in the very recent phase of assembly, installation and commissioning
of the ATLAS and CMS detectors that the enormous efforts and contribution from
the Technical Co-ordination teams have been most visible: they have had to organise
the vast teams of sub-contractors and specialised personnel from the collaborating
institutes and they have had to deal with the daily burden of making sure all the
tasks were executed as smoothly as possible with safety as one of the paramount
requirements.
16.3 Inner Tracking System
16.3.1 Introduction
The ATLAS tracker is designed to provide hermetic and robust pattern recognition,
excellent momentum resolution and both primary and secondary vertex measurements [17] for charged tracks above a given p T threshold (nominally 0.5 GeV, but
as low as 0.1 GeV in some ongoing studies of initial measurements with minimumbias events) and within the pseudorapidity range |η| < 2.5. It also provides electron
identification over |η| < 2.0 and a wide range of energies (between 0.5 and
150 GeV). It is contained within a cylindrical envelope of length ±3512 mm and of
radius 1150 mm, within the solenoidal magnetic field of 2 T. Figures 16.8 and 16.9
show the sensors and structural elements traversed by 10 GeV tracks in respectively
the barrel and end-cap regions.