Muon detectors
Muon Detectors
Overview of the muon system
The muon system instruments the iron yoke plates with layers of track sensitive chambers.
- Technology implemented: Glass Resistive Plate Chamber
- Solenoid central field: 3.57 T
- Magnetic field in the barrel region: -1.34 T
- Magnetic field in the endcap region: 0.01 T
| radius [mm] | |z| [mm] | #layers | sensor area [mm2] | cell size [mm2] | #channels [106] | |
|---|---|---|---|---|---|---|
| Barrel | 4461 < r < 6450 | < 4179 | 7 | 1942 | 30 x 30 | 2.2 |
| Endcap | 446 < r < 6450 | 4179 < |z| < 5700 | 6 | 1547 | 30 x 30 | 1.7 |
Beam-Induced Background
BIB muon hit spatial distribution in the first layer of the muon system endcap:
Number of hits per bunch crossing in each layer of the muon system:
Particle flux for rate calculation
BIB particles flux [Hz/cm2] in different regions (bunch crossing time 10 μs):
| Particle | Endcap (θ>12o) | Endcap (8o<θ<12o) | Endcap (θ<8o) | Barrel |
|---|---|---|---|---|
| photons | 6.2 · 102 | 1 · 104 | 7.2 · 105 | 5 |
| protons | 16 | 3 · 102 | 2.4 · 104 | ---- |
| e+ e- | 3 | 3.3 · 102 | 5 · 103 | < 1 |
| μ+ μ- | 3 | 3.7 · 102 | 1.2 · 104 | ---- |
| neutrons | 1.2 · 103 | 5 · 104 | 1.2 · 106 | 1.4 · 102 |
| pions, kaons | < 1 | 70 | 1 · 103 | ---- |
| Total | ≈ 2 kHz/cm2 | ≈ 60 kHz/cm2 | ≈ 2 MHz/cm2 | ≈ 200 Hz/cm2 |