724
D. Froidevaux
Table 16.9 Main parameters of the ATLAS pixel system
Number of hits per track
3
Total number of channels
80 · 10 6
Pixel size (μm in Rφ) × (μm in z/R)
50 × 400
Lorentz angle [degrees], initial. . . end
12. . . 4
Tilt in Rφ [degrees]
20 (only barrel)
Total active area of silicon [m 2 ]
1.7 (n + /n)
Sensor thickness [μm]
250
Total number of modules
1744 (288 in disks)
Barrel layer radii [mm]
50.5, 88.5, 122.5
Disk layer min.. . . max. radii [mm]
88.8. . . 149.6
Disk positions in z [cm]
49.5, 58.0, 65.0
Signal-to-noise ratio for m.i.p. (initial)
120
Total fluence at L = 10 34 (n eq /cm 2 /year)
3 · 10 14
at radius of 5 cm (innermost layer)
Signal-to-noise ratio (after 10 15 n eq /cm 2 )
80
Resolution in Rφ (μm)
≈10
Resolution in z/R (μm)
≈100
of close to 300 fb −1 . Table 16.9 shows the most relevant parameters concerning the
ATLAS pixel system.
Finally, Fig. 16.11 shows the results of test-beam measurements of the Rφ accuracy of production modules of the ATLAS pixel detector before and after being
irradiated with a total equivalent fluence corresponding to about 10 15 neutrons
per cm 2 [22]. These results are somewhat optimistic because they were obtained
with analogue readout and at an ideal incidence angle, but they nevertheless
demonstrate the extreme robustness of the pixel modules constructed for ATLAS.
This is one striking example of the painstaking validation work done in the early
phase of the construction years.
16.4 Calorimeter System
The design of the ATLAS calorimeter system is to a large extent the end product
of about 25 years of development and experience gained over several generations
of high-energy colliders and general-purpose experiments, all of which have
brought major advances in the understanding of the field. These advances range
from the concept of full coverage in total transverse energy at UA1, to that of
precision hadron calorimetry at ZEUS, and to that of very high granularity of the
electromagnetic calorimeters and the use of energy-flow techniques in the LEP
detectors [23].
D. Froidevaux
Table 16.9 Main parameters of the ATLAS pixel system
Number of hits per track
3
Total number of channels
80 · 10 6
Pixel size (μm in Rφ) × (μm in z/R)
50 × 400
Lorentz angle [degrees], initial. . . end
12. . . 4
Tilt in Rφ [degrees]
20 (only barrel)
Total active area of silicon [m 2 ]
1.7 (n + /n)
Sensor thickness [μm]
250
Total number of modules
1744 (288 in disks)
Barrel layer radii [mm]
50.5, 88.5, 122.5
Disk layer min.. . . max. radii [mm]
88.8. . . 149.6
Disk positions in z [cm]
49.5, 58.0, 65.0
Signal-to-noise ratio for m.i.p. (initial)
120
Total fluence at L = 10 34 (n eq /cm 2 /year)
3 · 10 14
at radius of 5 cm (innermost layer)
Signal-to-noise ratio (after 10 15 n eq /cm 2 )
80
Resolution in Rφ (μm)
≈10
Resolution in z/R (μm)
≈100
of close to 300 fb −1 . Table 16.9 shows the most relevant parameters concerning the
ATLAS pixel system.
Finally, Fig. 16.11 shows the results of test-beam measurements of the Rφ accuracy of production modules of the ATLAS pixel detector before and after being
irradiated with a total equivalent fluence corresponding to about 10 15 neutrons
per cm 2 [22]. These results are somewhat optimistic because they were obtained
with analogue readout and at an ideal incidence angle, but they nevertheless
demonstrate the extreme robustness of the pixel modules constructed for ATLAS.
This is one striking example of the painstaking validation work done in the early
phase of the construction years.
16.4 Calorimeter System
The design of the ATLAS calorimeter system is to a large extent the end product
of about 25 years of development and experience gained over several generations
of high-energy colliders and general-purpose experiments, all of which have
brought major advances in the understanding of the field. These advances range
from the concept of full coverage in total transverse energy at UA1, to that of
precision hadron calorimetry at ZEUS, and to that of very high granularity of the
electromagnetic calorimeters and the use of energy-flow techniques in the LEP
detectors [23].