Download - Minos Detector Experience in brief
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
Minos Detector Experiencein brief
Geoff Pearce, RALNF detector technology discussions
I.C. May 7, 2005
• The Minos Context• Detector Essentials & Elements• Assembly, installation, maintenance• Event reconstruction, resolutions, profiles• Finer grained calorimeter
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
Minos - context
Baseline : 730km
High intensity νμ beam from Fermilab to Soudan (Mn)
Two detectors, Near (1kT) and Far (5.4kT)
Primary measurement : Compare ν energy spectrum in the Far Detector to the un-oscillated expectation from the Beam and Near Detector
• Observe oscillation minimum
• Confirm oscillatory behaviour in νμ sector
• Measure Δm232 to ~10%
• Look for νμ → νe oscillations, measure θ13?
1kton near detector 5.4kton far detector
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
Minos – Energy Regime120GeV M.I. protons, graphite target
2.5 1013 / 8.67 µs pulse, 1.9s rep. rate (.25MW)
Beam energy can be tuned by adjusting position of 2nd horn relative to target
Both νµ and νµ beams_
Nominal Beam Configurations
Energy regime ~ 1 – 25 GeV
Δm2 expectation dropped considerably since conception/design
LE beam best match for Δm2 ~ 2-3 10-3 eV2 at the Minos baseline
Lower energy than NF, but not too disimilar
NF detector meetingIC, May 7 2005
Geoff Pearce, RALMINOS Far DetectorEssential features
5.4 kton magnetised tracking calorimeter, B ~1.5T
484 steel/scintillator planes built in 2 supermodules
2.54cm thick steel, 192 4x1cm scint. strips per plane
• orthogonal orientation on alternate planes – U,V
• optical fibre readout
Veto shield covers top/sides for atmospheric v
Multi-pixel (M16) PMTs read out with VA electronics
• 8-fold optical multiplexing
• chips individually digitised, sparsified & read out when dynode above a threshold
• excellent time resolution – 1.56ns timestamps
Continuous untriggered readout of whole detector
Interspersed light injection (LI) for calibration
Software triggering in DAQ PCs (independent of ND)
• highly flexible : plane, energy, LI triggers in use
• spill times sent from FNAL to FD trigger farm
GPS time-stamping to synch FD data to ND/Beam
Coil
Veto Shield
The completed Minos Far Detector
NF detector meetingIC, May 7 2005
Geoff Pearce, RALDetector Elements
U V U V U V U Vsteel
scintillator
orthogonal orientations of strips
4.1cm x 1cm extruded polystyrene strips
TiO2 reflective coating
Groove for 1.2mm WLS fiber to collect light
Steel scintillator sandwich
25.4mm steel, 1cm scintillator
Alternate planes have orthogonal strip orientations (U,V)
Fibres carry light to MAPMTs
M16 (FD) M64 (ND)
Optical multiplexing in FD
• 8 fibres per pixel
Scintillator strips in light-tight modules, 8/plane
192 scintillator strips on each plane
M16
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
Module Assembly & Testing
Placing Scintillator strips in light case
Design lends itself well to parallel construction
Matches many University workshop capabilities
Multiple factories for scintillator planes used by Minos
Division of labour – construction speed
Cost ~ $600 / module
Gluing WLS fibers
These can be important considerations
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
FD most challenging
• Remote (Soudan, Mn)
• narrow mine shaft
• taken down in pieces and assembled underground
ND planes assembled above ground
Both detectors installed to schedule
Detector assembly and Mounting
Installation / maintenance at remote location highly successful
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
MINOS Near DetectorEssential features
1 kton (total mass) magnetised tracking calorimeter
Partially instrumented
• 282 steel planes, 153 scintillator planes
• reduced sampling in rear planes (121-281) “spectrometer section” used for muon tracking
High instantaneous ν rate, ~ 20ev/spill in LE beam
No multiplexing except in spectrometer region (4x)
Fast “QIE” electronics
• continuous digitisation on all channels during spill
(19ns time-slicing). Mode enabled by spill signal.
• dynode triggered digitisation out of spill (cosmics)
GPS time-stamping / Software triggering in DAQ
• all in spill hits written out by DAQ
• standard cosmics triggers out of spill
Minos Near Detector as installation neared completion
Same basic design as Far Detector
NF detector meetingIC, May 7 2005
Geoff Pearce, RALEvent Reconstruction
‘u’ - view
‘v’ - view
ghost hits due to
multiplexing
plane #
stri
p #
Strip readout provides two 2D views (U,V) – combine to get 3D hits
Resolution ~ strip width (angular resoln. on moon shadow <0.5deg)
Multiplexing at FD complicates reconstruction, but soluble.
MC event – zoomed in
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
(Real) Far Detector Beam Event
νµ
NF detector meetingIC, May 7 2005
Geoff Pearce, RALNear Detector Eventsspecial needs
One spill in Medium Energy Beam
Intensity = 2.5 1013 pps
Multiple events in detector
Events resolved using timing
ND readout has 19ns bucket resolution
Near Detector must be able to cope with high rate
NF detector meetingIC, May 7 2005
Geoff Pearce, RALMagnetic Field
Stopping muonPrange = 3.86 GeV/c
Pcurvature = 4.03 GeV/c
B
PEs
time
VZ
UZ
1.5T magnetic field in steel generated by coil
• Momentum measurement
• Charge separation
Δpµ/pµ = 10% (curvature)
Δpµ/pµ = 6% (range – if available)
Far Detector cosmic muon (courtesy MT)
Good knowledge of field vital
NF detector meetingIC, May 7 2005
Geoff Pearce, RALCalibration DetectorThe 3rd major Minos detector
• Vital to understand energy response to reconstruct Eν
Eν = pµ + Ehad
• Minos design ports very well to test beam studies
• Can study detector issues vital to physics
• Minos built a 1m x 1m x 3.7m “mini-Minos and ran in CERN test beams to
• study response to π, µ, e, p
• test MC simulation
• look at near / far detector differences
• energy scale calibration
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
CalDet : sample events at 2 GeV
M. Kordosky
TOF/Cerenkov system at CalDet provides pure samples
Colour scale = MIPs
Energy distribution profile used to identify pid in Minos
NF detector meetingIC, May 7 2005
Geoff Pearce, RALMinos Calibration DetectorResponse to π, p, e
MC expectation
Preliminary
Energy Resolution
CalDet analysis nearing completion. Publications in preparation
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
MINOS Event Profiles
e CC Event
NC Event• often diffuse
NC Event
• can mimic , e
CC EventUZ
VZ
• +hadronic activity
• track
• compact shower
• typical EM shower profile
MCARLO
νe / NC
challenging but do-able at low energies.
NF detector meetingIC, May 7 2005
Geoff Pearce, RALBuilt for NDK, ~ 1Gev
1.6mm thin steel
(Minos has 25.4mm steel)
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
Soudan2 eventsHigh resolution
Bubble chamber quality
410 MeV electron shower
Gaps from γ propogation
Steel thickness can be tuned to needs -- and wallet
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
Summary and Conclusions
• Modular, simple, low risk, safe, not expensive • Magnet field can be applied over whole steel volume
– Momentum measurement– charge ID– You get iron.
• Sampling frequency, steel thickness can be chosen to match physics requirements
• Active components would be chosen to optimise cost/performance– Scintillator (eg liquid, like Nova)– Photodetectors (eg MA256, HPD, etc)– Electronics, DAQ would clearly be chosen from technology of the day
• Near detector can be same technology
• Minos style detector is an option worth consideration
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL
Soudan events
High energy event
fast exiting muon
two interacting pions
NF detector meetingIC, May 7 2005
Geoff Pearce, RAL