364
L. Camilleri
the last four modules which used a single scintillator plane for triggering. The drift
chambers were 4 m wide hexagons and drifted vertically or at ±60 ◦ to the vertical
in order to resolve ambiguities. The average efficiency was typically 99.5% and the
spatial resolution 0.7 mm, which was adequate given the contribution of multiple
scattering in the iron.
NuTeV/CCFR [92] used at Fermilab for a similar range of neutrino energies,
differed from CDHS in that the calorimeter was separate from the magnetic
spectrometer used to measure muon momenta. The 690 ton calorimeter consisted
of 168 3 × 3 × 5.15 cm steel plates instrumented with Bicron 517L scintillator oil
counters placed every two plates and drift chambers every four plates. This was
followed by the magnetized iron toroidal spectrometer with an inner diameter of
25 cm to accomodate the four coils and an outer diameter of 350 cm. It consisted of
three sections each followed by a drift chamber and two additional drift chambers
downstream of the last section for improved momentum resolution. An important
feature of this experiment was that a calibration beam was available in situ to
determine the response [92] of the detector to electrons, muons and hadrons. The
hadronic resolution was σ E /E = 0.86/
√
E(GeV )
0.022 with an absolute scale
uncertainty of 0.43%. The muon scale uncertainty was 0.7%, dominated by the field
map determination in the iron. NuTeV performed a precise measurement of sin
2 θ W
necessitating the measurement of both neutral and charged current events. They
discriminated between the two on the basis of event length defined as the number of
scintillator planes with non-zero pulse height in an event.
The 5.4 kiloton, 31 m long MINOS detector [93], similar in concept to CDHS,
consists of 486 2.54 cm thick iron plates interleaved with planes of scintillator
strips read by wave length shifting fibres. It was exposed to the Fermilab NuMI
beam and housed in the Soudan mine 735 km away from Fermilab. This detector
is studying ν μ disappearance and therefore the shape and magnitude of the beam
energy distribution must be very well understood. To minimize its dependence on
Monte Carlo calculations the experiment is equipped with a near detector, located
1015 m from the target, which measures the beam spectrum and composition before
any significant oscillations can occur. A transfer matrix is then used to predict the
flux at Soudan. The transformation does not depend simply on the inverse of the
square of the distance to the detector as the near detector, being close to the target,
is not exposed to an exact point source because of the finite (725 m) length of the
decay tunnel. The extruded polystyrene scintillator strips are 4.1 cm wide and 1 cm
thick and are read by a 1.2 mm wave-length shifting fibre housed in a groove. The
fibres are read by multi-anode photomultipliers, structured as 16 pixel in the far
detector and 64 pixel in the near one. The data is multiplexed to reduce the number
of readout channels. The coil provides a toroidal magnetic field in the iron allowing
the measurement of the momentum and charge of secondary muons.
L. Camilleri
the last four modules which used a single scintillator plane for triggering. The drift
chambers were 4 m wide hexagons and drifted vertically or at ±60 ◦ to the vertical
in order to resolve ambiguities. The average efficiency was typically 99.5% and the
spatial resolution 0.7 mm, which was adequate given the contribution of multiple
scattering in the iron.
NuTeV/CCFR [92] used at Fermilab for a similar range of neutrino energies,
differed from CDHS in that the calorimeter was separate from the magnetic
spectrometer used to measure muon momenta. The 690 ton calorimeter consisted
of 168 3 × 3 × 5.15 cm steel plates instrumented with Bicron 517L scintillator oil
counters placed every two plates and drift chambers every four plates. This was
followed by the magnetized iron toroidal spectrometer with an inner diameter of
25 cm to accomodate the four coils and an outer diameter of 350 cm. It consisted of
three sections each followed by a drift chamber and two additional drift chambers
downstream of the last section for improved momentum resolution. An important
feature of this experiment was that a calibration beam was available in situ to
determine the response [92] of the detector to electrons, muons and hadrons. The
hadronic resolution was σ E /E = 0.86/
√
E(GeV )
0.022 with an absolute scale
uncertainty of 0.43%. The muon scale uncertainty was 0.7%, dominated by the field
map determination in the iron. NuTeV performed a precise measurement of sin
2 θ W
necessitating the measurement of both neutral and charged current events. They
discriminated between the two on the basis of event length defined as the number of
scintillator planes with non-zero pulse height in an event.
The 5.4 kiloton, 31 m long MINOS detector [93], similar in concept to CDHS,
consists of 486 2.54 cm thick iron plates interleaved with planes of scintillator
strips read by wave length shifting fibres. It was exposed to the Fermilab NuMI
beam and housed in the Soudan mine 735 km away from Fermilab. This detector
is studying ν μ disappearance and therefore the shape and magnitude of the beam
energy distribution must be very well understood. To minimize its dependence on
Monte Carlo calculations the experiment is equipped with a near detector, located
1015 m from the target, which measures the beam spectrum and composition before
any significant oscillations can occur. A transfer matrix is then used to predict the
flux at Soudan. The transformation does not depend simply on the inverse of the
square of the distance to the detector as the near detector, being close to the target,
is not exposed to an exact point source because of the finite (725 m) length of the
decay tunnel. The extruded polystyrene scintillator strips are 4.1 cm wide and 1 cm
thick and are read by a 1.2 mm wave-length shifting fibre housed in a groove. The
fibres are read by multi-anode photomultipliers, structured as 16 pixel in the far
detector and 64 pixel in the near one. The data is multiplexed to reduce the number
of readout channels. The coil provides a toroidal magnetic field in the iron allowing
the measurement of the momentum and charge of secondary muons.