mcp based photodetectors for cryogenic applications

MCP based photodetectors for cryogenic applications

Bob Wagner for Ranjan Dharmapalan

Argonne National Laboratory CPAD 2015

University of Texas, Arlington

Argonne Photodetector R&D

Noble Liquid Detectors for Particle Physics

‣ Many current and near term particle physics experiments using noble liquids as detector medium

• Neutrino - µBooNE, SBND, LArIAT, DUNE

• Dark Matter search - CLEAN, LUX, XENONnnn

• Others - nEDM (He)

‣ Scintillation Light • Liquid is transparent to produced light • VUV: 128nm LAr 175nm LXe • Large signal (~10k γ/MeV for LAr)

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DOE Site Visit at ANL HEP Cryogenic MCP-PMTs

Noble Liquids in Experimental Physics‣ Many current and upcoming physics experiments using

noble liquids as detector medium. • Neutrino

- uBooNE, SBND, LArIAT, DUNE • Dark Matter search

- CLEAN, LUX, XENON • Others

- nEDM (He)

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ArgoNeut data:






- nEDM (He)

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ArgoNeut data:






- nEDM (He)

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ArgoNeut data:

Current Photon Detection Methods in Noble Liquids

‣ Use SiPMs or PMTs + wavelength shifter • t0 for reconstruction • background rejection

‣ Limitations • WLS degrades timing resolution • WLS handling • Limited position resolution

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Current Photon Detection Methods in Noble Liquids‣ Use SiPMs or PMTs and wavelength shifting (WLS)

• Used to get t0 for reconstruction • Background rejection !

‣ Cons: • WLS degrades timing resolution • WLS handling • Form factor (in case of PMTs) • Limited position resolution (light guides)

4DOE Site Visit at ANL HEP Cryogenic MCP-PMTs

Current Photon Detection Methods in Noble Liquids‣ Use SiPMs or PMTs and wavelength shifting (WLS)

• Used to get t0 for reconstruction • Background rejection !

‣ Cons: • WLS degrades timing resolution • WLS handling • Form factor (in case of PMTs) • Limited position resolution (light guides)

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MCP-based PMTs as Alternative for Cryogenic Detector

‣ Micro-channel plate (MCP) based photodetectors are capable of imaging, and having good spatial and temporal resolution.

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MCP-PMTs at Argonne

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ANL focus: 6 cm devices

Final goal: 20 cm

Traditional PMT MCP-PMT

‣ The Argonne MCP Photodetector program seeks to develop improved, lower cost MCP photodetectors: ‣ New MCP: borosilicate glass capillary array coated by Atomic Layer

Deposition (ALD). Very robust, large-area (20×20cm2).High gain: secondary emission layer engineered by ALD

‣ New packaging: all-glass package with an thermopressure indium seal

Argonne is focused on producing 6x6 cm2 small form-factor detectors, as a way to optimize the manufacturing process, for testing and getting devices out to the community.

MCP-PMTs Components

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MCP-PMT Major Components: - A glass anode plate with strip line readout - A glass side wall which is glass-frit bonded to the bottom plate - A pair of MCPs coated by Atomic Layer Deposition (ALD) - A glass top window with a bialkali photocathode - An indium seal between the top window and the sidewall.

Argonne Small Tube Processing System

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Argonne Small Tube Processing System

‣ Production facility and R&D platform

‣ ~1 device / 2 weeks

‣ 6 functional detectors with internal resistive grid spacers to bias MCPs

‣ 4 functional detectors with modified design for individual MCP biasing

- <50 ps time resolution for single-PE - <15 ps time resolution for multi-PE - <0.8 mm position resolution for large pulses

Typical MCP signal

‣ Pulse width: ~2-5 ns ‣ Rise time: ~700 ps ‣ Fall time: 2 - 3 ns

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Raw

Filtered

QE & Gain

‣ Photocathode QE scan measured at 350nm ‣ Gain was measured in single photoelectron mode

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QE scan Gain VS HV

Gain: ~107

¾ Average QE ~14% ¾ Better uniformity in large area ¾ Possible reason for the QE map shape: The flow of the precursor from effusion cell causes a temperature and precursor concentration gradient along the glass substrate, resulting lower QE at the direction of the pumps.

Tube #47 QE vs. wavelength and Map (2nd day)

To loadlock turbo

To ion pump

Projection of a pin for photocurrent monitoring during growth

~14% average QE

Time resolution

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▪ The light intensity is calibrated by the number of photoelectrons. Results are independent of the quantum efficiency (QE) of the photocathode.

σ VS HV (<Npe> < 0.2) σ VS <Npe> HV=2560V

57 ps15 ps

Position resolution / differential time resolution

‣ Dependent on the Noise/Signal ratio. ‣ Limited by the electronics (~7ps) and the beam size (~1mm)

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lt rt

Position distribution

Electronics & beam size

0.7mm (7.6 ps)

Large pulses Small pulses

Customizing MCP-PMTs for cryogenic applications

‣ Test the performance of individual components in cryogenic environment

‣ Tune, modify the component to achieve desired performance, e.g. fused silica or MgF window to replace borosilicate glass

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Window with photocathode

MCPs

Grid spacers

Anode base plate

6x6 cm2 ‘small tile’

Indium wire

‣ Structural integrity in cryogenic environment

• Indium seal • Glass frit bond

‣ Dunked device in LN2 ‣ Performed “slow” dunk and “fast” dunk ‣ for >48 hours at a time ‣ 4 devices tested (2 fully sealed) 1 failure

• Failure due to hairline crack on sidewall

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Indium seal

frit bond

Testing the seals

Tuning the MCP for cryogenic temperature

The Atomic Layer Deposition (ALD) : self-limited nanostructure deposition method. Precursors applied separately —excellent control over material growth and hence the MCP parameters

Working with Argonne Energy System Division (Anil Mane and Jeff Elam) on development of resistive and SEE coatings for MCPs.

Have produced two MCPs with lowered room temperature resistance that hit target resistance at LN2

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Development of Lower Cost Large Area MCP Photodetector, R. Wagner, Argonne, LIGHT11, Ringberg Castle, 20111101

Pore Activation via Atomic Layer Deposition (ALD)

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AlCH3

AlCH3

CH3

CH3OH OH OH

AlCH3

AlCH3CH3

OH OH OH

Al(CH3)3

Trimethyl Aluminum(TMA) O O O

AlCH3CH3

H2O

OH

OH OH OHAl Al

OHOH

Example:

• OH on surface provide reaction sites• Trimethyl aluminum reacts liberating methane, forms Al2O3 layer. Leaves methyl group inhibiting further reaction on surface• Exposure to H2O removes methyl group. Leaves OH sites for next reaction

pore

pore

1 KV

pore

pore

Resistive ALD

Emissive ALD

Conductive Electrode

Wednesday, November 2, 2011

conductive electrode

resistive ALDemissive ALD (AlO, MgO)

pore

R VsTime

R(oh

m)

1.00E+06

1.00E+07

1.00E+08

1.00E+09

1.00E+10

1.00E+11

1.00E+12

Time (sec)

0 125 250 375 500

Dip in liquid N2

‣ MCPs operational in cryogenic temperature developed • Test stability at 87K • Cryogenic behavior of ALD materials being explored • Gain measurements underway

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Tuning the MCP for cryogenic temperature

Photocathode for UV and low temperature

‣ Literature survey shows GaN, CsI works • Test cryogenic behavior

‣ Designed setup for testingQE vs temperature

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O. Siegmund et al

128 nm

‣ After preliminary tests at Argonne, seek to use the liquid argon test facilities at Fermilab.

‣ Looking at geometries and simulation • See how MCP-PMTs perform

Testing Simulations Physics capabilities

Testing/Simulation

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Window with photocathode

MCPs

Grid spacers

Anode base plate

Plans for Argonne MCP-PMTs

‣ Different geometries, smaller MCP pore size (10 µm) ‣ Pad readout ‣ Photocathode research ‣ Neutron detector

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Argonne MCP-PMT:

Other ideas welcome! Open to collaboration with early adopters: Please tell us about your new ideas

Plans for Argonne MCP-PMTs

‣ Bare MCP detector for two phase detectors ‣ Use MgF top window (no WLS)

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Cryogenic Applications

Other ideas welcome! Open to collaboration with early adopters: Please tell us about your new ideas

Summary

‣ Argonne Detector R&D group has successfully produced working MCP based detectors.

‣ Developing MCP photodetectors to operate in liquid argon. • Tuning MCP resistance for cryogenic operation • Assessing candidate photocathode materials for low T operation

‣ Seeking to demonstrate operation at LAr temperature with tuned MCPs and appropriate photocathode

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mcp based photodetectors for cryogenic applications

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