secondary emission ionization calorimetry detectors david r winn for fairfield/iowa/mississippi
Post on 29-Dec-2015
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Secondary Emission IonizationCalorimeters
•Secondary Emission: Rad-Hard, Fast– Metal-Oxide/Cs Dynodes survive > 500 GigaRad
•Signal from SE surface(s) in Hadron Showers: – SE yield Scales with particle momentum ~dE/dx– e-: 3 < <100, per 0.1 <e-<100 KeV (material depnt)– ~1.05 -1.1 or 0.05-0.1 SE e- per MIP NB: This is a lower limit on hadron shower SE signals– 4-6 MIP equiv per GeV sampling calorimeters– ~50 SE e- per 100 GeV pi shower w/ MIPs alone
• Achtung! SE e- Must be Amplified!
Al2O3,TiO2
~0.05 e- per MIP. Yet used as beam monitors:Rad Hard!
HadronShowers:Sub-mipCharged particles
Signal Generation from e, pi Showers
0
5
10
15
20
25
30
1E+16 1E+17 1E+18 1E+19 1E+20
B Doping Level (cm-3)
1St Dynody Gain
High SE Yield MaterialsPeak Yields~5-10+; Alumina Easy
MgO
DiamondSE YieldStable in
air!
Electrons on MgO
Diamond Gain 300 V vs B Doping Level
~5cm Fe Sampling HCal:~4-6 mip equiv/GeVThe Lower Limit on Signal:
100 GeV Fe Hadron Cal:Minimum of 25-50 SE e-…But need amplifier!
SE Signal: MIP Equivs in Hadron Calorimeter
->800 SEe/GeV(100 events)
GEANT4: Cu, 1cm plates, 10 GeV e incidentElectrons counted as cross 1cm “gap”
Showering e energy
10 GeV e
100 GeV e
Implies~900 e/GeV
Crossing gaps.
Implies > 45 SEe/GeV !
GEANT4 e’s in Cu1 cm absorber Plates
Count shower e crossing gapsNumber shower e vs e energy
SE e Detector Option A: Etched Metal Sheet Dynodes
- Chemo-electro machined Metal “Mesh” Dynode Sheets-~1mm thick dynode layer - scale to 500-200 µm- HV Vacuum: <10KV/mm -> 500V/0.2 mm ok.- Sheets can be up to square meters- Pressure + HV insulators: monotonous insulators
-walls, posts, fibers (glass ceramics oxides)- Quasi Channelized: e- confined ->MCP operation - Metal cathode directly D1- B -> ~2T, as mesh dynode PMT
Hamamatsu Slat Dynodesup to 6” now. Can be Scaled.
fine mesh distance between dynodes: 0.9 mm step of the dynode mesh: 13 mm mesh wires diameter: 0.5 mm
SE e Detector Option B: Metal Screen Dynodes: 15D: g~105, Bz~2 T
µMachined Mesh DynodesLow Cost ~ 30 minute processChannel Width ~200 mOffset layer layer helical channelsInsulator: Si3N4 or SiO2Confined e- = High BCan be taken to air repeatedly~ microTorr operation ok
SE e Detector Option C: MEMS Mesh Dynodes
A - El-Mul/A.BreskinSintered SE MicroSpheres ~20- 100 µmPorous Plate: ~0.5-1 mm thickGain ~ 106 at 3000 V @ 1G
Alternative High-B SE e- Gain Mechanisms:MCP-Like Devices
B - Anodic Alumina ~ MCP-like?~100 nm poresAspect ratio ~ 50-100:1
Minimum Signal: muon MIP~0.1 SE e- per module w/ g > 100,000 (delta rays~SE peak)~ 40 Samples -> MIP Signal ~ 4 SE electrons/MIP ~ 2 “SE electron”/GeV @ 105/SEe
Hadron Shower Signal:Larger SE e per GeV - particles of lower momentum:
->SE ~1.5-6 compared with 1.1-1.05 for MIP. <E> ~ 60 MeV/2cm cube; Calice: ~23 “particles”/Hadron GeVGEANT4 MC: ~740 charged hits/GeV ~35-75 SEe -> 4-75 SEe/GeV hadron calorimeter showers
Electron Shower Signal:GEANT4 MC: ~900 SEe/GeV ~45-90 SEe
N.B.: e/pi ~ 0.8 - possible compensation
Anticipated Performance:SE 12 Cu Hadron Calorimeter
Secondary Emission Calorimeter Sensor Basics:
- Top Metal Cathode, thin film SE inner Surface – Square/Hex/ –can be thick!
- Ceramic (Green Form) Edge Wall; HV feedthrus, supports; ~1cm high
- Dynode Stack – mesh, MCP, slats, etc ~5-10 mm
- Bottom Metal Anode – thick/identical to Cathode/Vacuum pump tip;-
SLHC R&D technology –Secondary Emission Sensor Modules for Calorimeters
Schematic SEM Calorimeter Sensor Module - Plate Cathode/Anode Option
brazed ceramic insulators
10 mil HV insulator (polymer)
signal (male)
signal (female) -optional for stacking
film bias resistor chain
1.8 mm thick Cu
HV connector
HV female socket (optional for stacking)
stackable
-2kV
signal out6 dynodes (200 µm thick @ 0.8mm spacing) 50?
2 silicon micro channel plates
Cs3Sb SEM Surface
1cm
15 cm
top view
ceramic
Cu plate
- Similar to m2 Low Pressure Gas Plasma Display Technology - Proof of Principle/Manufacture - SE Calo sensor far simpler- Hermetic + Voltages similar to dynodes- Vacuum Supported by Ceramic walls or posts -> thin metal windows
SE Calorimeter Manufacture Issues
Ceramic Body 2.5” MCP-PMT
SE Calorimeter R&D technology Secondary Emission Sensors for Calorimeters
• Basic Idea: Dynode/SE Stack is a High Gain Radiation Sensor- High Gain & OK Efficient (MgO yield ~0.1 e/mip per sample)- Energy Resolution: stochastic term ~10-50 SEe/GeV- Compact (micromachined metal ~0.3-1mm thick/stage)- Rad-Hard (PMT dynodes>100 GRads)- Uber-Fast- Potentially low cost/Non-Critical Assy- Simple Al oxide SEM monitors proven at accelerators - Rugged/Could be structural element- Easily integrated into large calorimeters/Arbitrary Shapes- ~Minimal Dead Areas- Minimal services needed.
SE Detector Modules Are Applicable to:- Energy-Flow Calorimeters (e+e-, µC, SLHC,….)- Forward HiRad HiRate Calorimeters- Compensation
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