1. Detector  Basically the NOvA detector. Planes of plastic tubes filled with liquid scintillator. Fully active: Good for electron identification Total mass: 30 kilotons. 150m long, 15.7m x 15.7 m.  Surrounded by coils providing a magnetic field.  Use the ATLAS toroid coils as examples.  The advantage over a magnetic iron detector is that it also gives us a handle on the momentum and charge of the hadrons as well as those of the muons.  NOMAD was a successful magnetic detector that used this principle.

2. Detector concept: End view Detector Coil Return yoke

3. Detector concept: Side view 10 coils per side

4. More details  ATLAS has 8 rectangular coils each 25m x 5m. Superconducting.  120 turns per coil  20.5 kA  Field at centre 0.41 T  Cost is 75 MCHF  NOvA is 15m high, so lets’s modify the coil to 15m x 15m  same circumference  NOvA is ~ 150m long, so we would need 10 coils on either side  20 coils  We don’t need such a big field for the charge: drop it to 0.15T.  Reduce the number of turns/coil.  Does the decrease in number of turns compensate the increase in number of coils?  Do we need a superconducting setup?  With such a small field and with iron saturating at about 1.8T, the cross section of the return yoke need only be 25m x (15m x 0.15/1.8) ~ 25m x 0.75m per coil pair

5. Performance  Each tube: 15.7m long, 3.8cm transverse to the beam, 6cm along the beam.  Precision per coordinate 3.8 / (12) 1/2 = 1.2 cm.  Track length given by muon range, but taken to be maximum of 50m. Momentum(GeV/c)Range(m)Curvature(1/R) m -1 # Stand. dev 2 10.4 0.06 5.6 6 29.7 0.02 10.0 10 48.2 0.012 13.0 20 92.6 0.006 13.0 30 135.7 0.004 13.0 50 219.2 0.0024 13.0