Status of ALD MCP Program at Argonne within last Six Months Qing Peng, Anil Mane, Joe Libera, Jeffrey Elam Energy Systems Division

MCP Structure 2 1)resistive coating (ALD) 2)emissive coating (ALD) 3)conductive coating (thermal evaporation) pore

Work Plan and Deliverables Year 1 Emissive coatings Resistive coatings Year 2 Stripe coating (“Dynode Chain”) MCPs from AAO templates Begin scale-up Year 3 Scale-up 3 Majority of Year One goals completed!!!

Six months Ago Only ALD available 4

Right Now New Hardware: Measurement 5 Mercury probe – conductance of thin films in air, computer controlled Fixture for electrode evaporation with end spoiling on 3 MCPs Vacuum setup – HV conductance and thermal coefficient of MCPs Shadow mask – measure lateral resistance of thin films Order placed Various substrate holders Have been built

General procedures for Fabrication of MCPs Pristine MCPs Acetone sonication clean Air dry at 200C >2h Loading in Vacuum reactor Ozone clean ALD coatings Baking at 400C under N2 Electrode coating Testing resistance Deliver for testing 30mins2 hrs 10 hrs 6 hrs 3 hrs 4 hrs For fabricating one pair MCPs: ~20-30hrs if everything is right

Resistive Coatings: Al 2 O 3 /ZnO (AZO) 7 Good: existing process Bad: hard to control (etching of ZnO by trimethyl aluminum precursor) Can we make working MCPs with AZO? Still working on it Problem: Big slope (10 5 resistance change over 10% composition change) Etching of ZnO by trimethyl aluminum precursor Strong dependence of resistivity on Annealing conditions Strong dependence of resistivity on environment etching AZO can be prepared by a variety of methods Unable to eliminate etching

120C 100C 80C 60C 40C 25C Temperature dependence of 20% AZO conductivity 8 Gas chromatograph (GC) for temperature control MCPs in in GC with leads Standard Glass MCP: β T =-0.02 Micromachined silica MCP: β T = Commercial MCP (using our setup): β T = % AZO MCP: β T =-0.06

Resistive coatings: MgO/ZnO (MZO) 9 No etching in MZO Resistance is tunable MgO is candidate for SEY layer No MCPs made yet with MZO Thickness (Angstroms) Quartz Microbalance Data: Will work more on this system.

Resistive Coatings: “New Chemistry 1” 10 No etching Resistance is tunable, small slope (10 2 over 10%) Very reproducible (different locations, different batches) MCPs work: (20 micron, 60 L/D, 1x10 6 gain at 1200V) 11 MCPs to testing group Relative Composition MCP Resistance (Ohms)

Temperature coefficient – “New1” 11 Standard Glass MCP (literature): β T =-0.02 Commercial MCP (using our setup): β T = % AZO MCP: β T =-0.06 New1: β T =-0.027

Emissive Coatings Substrates: Si(100) - conductive, smooth, flat, cheap Photonis MCPs ALD MCPs Films: Al 2 O 3, MgO, SiO 2, ZnO/Al 2 O nm Major parameters to investigate: Annealing conditions Deposition conditions 55 samples to characterization group Goals: Manuscript on ALD emissive coatings Optimal thickness and composition for ALD MCPs 12 ALD No ALD

Electrode Deposition Thermal evaporator (Au) Hau Wang, MSD: Au has poor adhesion, can’t do endspoiling E-beam coaters (NiCr) Orlando Auciello, MSD Beihai Ma, ES Robert Erck, ES John Pearson, MSD Wai Kwok, MSD Eileen Hahn (FermiLab) CNM  Proposal accepted, Ebeam working for three weeks. Can’t do endspoiling Outside ANL: Clausing, Arradiance, Photonis (sent samples 3 weeks ago) Electrode first???

Future Plans AZO: Manuscript on AZO MCPs Explore anisotropy of conductance (thru film vs. across film) MZO: Manuscript on “ALD method” Make and test MCPs “New1”: Complete study Continue making and testing MCPs “New2”, “New3”… Scale-up large area coater, Beneq (4/26/10) 14