Secondary Emission Ionization Calorimetry Detectors David R Winn for Fairfield/Iowa/Mississippi

Secondary Emission Ionization Calorimeters 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!

Signal Generation from e, pi Showers Al2O3,TiO2 ~0.05 e- per MIP. Yet used as beam monitors: Rad Hard! Hadron Showers: Sub-mip Charged particles

High SE Yield Materials Peak Yields~5-10+; Alumina Easy MgO Electrons on MgO Diamond SE Yield Stable in air! Diamond Gain 300 V vs B Doping Level

SE Signal: MIP Equivs in Hadron Calorimeter ~5cm Fe Sampling HCal: ~4-6 mip equiv/GeV The Lower Limit on Signal: 100 GeV Fe Hadron Cal: Minimum of 25-50 SE e- …But need amplifier!

Digital Calorimetry: ~12 hits/GeV ->0.5-1 SEe/GeV (CALICE) B.Bilki et al., 2009 JINST 4 P04006

->800 SEe/GeV GEANT4: Cu, 1cm plates, 10 GeV e incident Electrons counted as cross 1cm “gap” ->800 SEe/GeV (100 events) Showering e energy

Implies ~900 e/GeV Crossing gaps. > 45 SEe/GeV ! GEANT4 e’s in Cu 1 cm absorber Plates Count shower e crossing gaps Number shower e vs e energy 10 GeV e Implies ~900 e/GeV Crossing gaps. > 45 SEe/GeV ! 100 GeV e

~740 Charged Particles/GeV More low E than electron -> ~35-80 SEe/GeV

SE MIP Detector w/ 5 x 107 Gain SE e- Already In Vacuum Use Dynodes To Amplify

Etched Metal Sheet Dynodes SE e Detector Option A: Etched Metal Sheet Dynodes Hamamatsu Slat Dynodes up to 6” now. Can be Scaled. - 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

5” wide PMT Etched Dynodes

Metal Screen Dynodes: 15D: g~105, Bz~2 T SE e Detector Option B: Metal Screen Dynodes: 15D: g~105, Bz~2 T 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 C: MEMS Mesh Dynodes µMachined Mesh Dynodes Low Cost ~ 30 minute process Channel Width ~200 mm Offset layer layer helical channels Insulator: Si3N4 or SiO2 Confined e- = High B Can be taken to air repeatedly ~ microTorr operation ok

Alternative High-B SE e- Gain Mechanisms: MCP-Like Devices A - El-Mul/A.Breskin Sintered SE MicroSpheres ~20- 100 µm Porous Plate: ~0.5-1 mm thick Gain ~ 106 at 3000 V @ 1G B - Anodic Alumina ~ MCP-like? ~100 nm pores Aspect ratio ~ 50-100:1

Anticipated Performance: SE 12 l Cu Hadron Calorimeter 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 GeV GEANT4 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

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; -

Schematic SEM Calorimeter Sensor Module - Plate Cathode/Anode Option SLHC R&D technology –Secondary Emission Sensor Modules for Calorimeters Schematic SEM Calorimeter Sensor Module - Plate Cathode/Anode Option

SE Calorimeter Manufacture Issues - 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 Ceramic Body 2.5” MCP-PMT

Basic Idea: Dynode/SE Stack is a High Gain Radiation Sensor 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