708
D. Froidevaux
Serious technical problems in this area have affected the manufacturing schedule
of major components of both experiments (hybrids for semi-conductor detectors,
flexible parts of printed-circuit boards, large-size electrodes for electromagnetic
calorimetry), but other issues such as welding, brazing and general integrity and
leak-tightness of thin-walled cooling pipes have also been a concern for several
of the components in each experiment.
In addition, several of the more significant contracts were seriously affected by
changes in the industrial boundary conditions (insolvency, change of ownership).
The recommended purchasing strategy of having multiple suppliers for large
contracts, to minimise the consequences from a possible failure in the case of a
single supplier, has not always been the optimal one (high-quality silicon sensors
are perhaps the most prominent example).
The detailed construction planning can be consulted in the various Technical
Design Reports (TDR), most of which were submitted from 1996 to 1998 to
seek approval for construction of the major detector components. This called for
completion of this construction phase by mid-2001 to mid-2003. At the time when
a big schedule and financial crisis shook the LHC project in fall 2001 (see below),
it was already clear that many detector components would not be on schedule by a
significant margin.
The 2-year delay in the completion of the accelerator resulting from this crisis
was also needed by the experiments, as can be seen from Table 16.5, which
illustrates the major construction milestones originally planned at the time of
the TDRs and actually achieved. When trying to assess the significance of the
differences between the dates achieved for the delivery of major components of
Table 16.5 Main construction milestones for the ATLAS and CMS detectors
Detector system
ATLAS
CMS
TDR
Actual
TDR
Actual
Pixels
06/03
03/07
03/05
12/07
Silicon micro-strips (barrel)
12/02
07/05
03/04
10/06
Silicon micro-strips (end-caps)
12/02
06/06
03/04
10/06
Transition radiation tracker
03/04
12/05
Electromagnetic calorimeter
(barrel)
06/03
07/04
12/03
03/07
Electromagnetic calorimeter
(end-caps)
01/04
09/05
06/04
03/08
Hadronic calorimeter
12/02
02/04
12/03
12/04
Muon chambers
12/04
12/05
12/03
06/06
Solenoid magnet
01/02
09/01
03/03
12/05
Barrel toroid magnet
06/02
06/05
End-cap toroid magnet
12/03
11/06
Shown are the milestones for the delivery of major components to CERN, as planned at the time
of the Technical Design Reports (TDR), and the actual delivery milestones achieved
D. Froidevaux
Serious technical problems in this area have affected the manufacturing schedule
of major components of both experiments (hybrids for semi-conductor detectors,
flexible parts of printed-circuit boards, large-size electrodes for electromagnetic
calorimetry), but other issues such as welding, brazing and general integrity and
leak-tightness of thin-walled cooling pipes have also been a concern for several
of the components in each experiment.
In addition, several of the more significant contracts were seriously affected by
changes in the industrial boundary conditions (insolvency, change of ownership).
The recommended purchasing strategy of having multiple suppliers for large
contracts, to minimise the consequences from a possible failure in the case of a
single supplier, has not always been the optimal one (high-quality silicon sensors
are perhaps the most prominent example).
The detailed construction planning can be consulted in the various Technical
Design Reports (TDR), most of which were submitted from 1996 to 1998 to
seek approval for construction of the major detector components. This called for
completion of this construction phase by mid-2001 to mid-2003. At the time when
a big schedule and financial crisis shook the LHC project in fall 2001 (see below),
it was already clear that many detector components would not be on schedule by a
significant margin.
The 2-year delay in the completion of the accelerator resulting from this crisis
was also needed by the experiments, as can be seen from Table 16.5, which
illustrates the major construction milestones originally planned at the time of
the TDRs and actually achieved. When trying to assess the significance of the
differences between the dates achieved for the delivery of major components of
Table 16.5 Main construction milestones for the ATLAS and CMS detectors
Detector system
ATLAS
CMS
TDR
Actual
TDR
Actual
Pixels
06/03
03/07
03/05
12/07
Silicon micro-strips (barrel)
12/02
07/05
03/04
10/06
Silicon micro-strips (end-caps)
12/02
06/06
03/04
10/06
Transition radiation tracker
03/04
12/05
Electromagnetic calorimeter
(barrel)
06/03
07/04
12/03
03/07
Electromagnetic calorimeter
(end-caps)
01/04
09/05
06/04
03/08
Hadronic calorimeter
12/02
02/04
12/03
12/04
Muon chambers
12/04
12/05
12/03
06/06
Solenoid magnet
01/02
09/01
03/03
12/05
Barrel toroid magnet
06/02
06/05
End-cap toroid magnet
12/03
11/06
Shown are the milestones for the delivery of major components to CERN, as planned at the time
of the Technical Design Reports (TDR), and the actual delivery milestones achieved