6 Calorimetry
227
Fig. 6.21 Measured average fractional containment in iron of infinite transverse dimension as a
function of thickness and various pion energies [38, 39]
16
14
12
10
8
6
4
1
1 0
1 0 2
10 3
10 4
p T (GeV)
Total thickness (λ)
Jet containment at 98%
MC FCC mean
MC FCC peak
Fig. 6.22 Total thickness, expressed in λ, to contain up to 98% of a jet as a function of the jet
transverse momentum. Mean and peak refer to different statistical measures of containment [40]
These results indicate that for 98% containment at the 100 GeV scale a
calorimeter depth of 9 λ int is required. At the LHC, where single particles energies
in the multi-hundred GeV and jets in the multi-TeV range have to be well measured,
the hadrons are typically measured in 10 λ int . For the next jump in collider energy,
as is presently studied e.g. for “Future Circular Collider, FCC”, particle and jet
energies are approximately a factor 10 higher. For adequate containment, i.e. at the
98% level, calorimeter systems with ~12 λ int will be required, see Fig. 6.22 [40]