MCP Photodetector program Lei Xia ANL - HEP

Outline  Understand the capability  Scientific opportunities and R&D need  MCP photodetector R&D program 2

Understand our capability: core processing facilities 3 BENEQ commercial ALD system for MCP R&D, production (ES/HEP Division) Small tile processing facility (STPS), routinely produce sealed working MCP photodetectors in a very flexible way

Understand our capability: core testing facilities 4 Phosphor screen chamber for MCP test Photo cathode test stand Photodetector laser test stand Cryogenic test setup

Understand our capability: core processes  MCP processing –MCP resistive layer coating: several home developed recipes –MCP secondary emissive layer coating: home developed materials + possible others –Routine MCP production –Strong MCP R&D capabilities  Photocathode fabrication –Routine bi-alkali photocathode fabrication in BURLE system, QE ~20-25% BURLE system is a commercial system for cathode deposition studies using dispensers –Routine bi-alkali photocathode fabrication in STPS working tube QE ~13%, cathode only tube QE ~16% –R&D capability on different photocathodes  Glass packaging fabrication –Unique Argonne scientific glass shop –All glass packaging will lead to significantly lower device cost  6cm photodetector fabrication –Routine production of sealed, working and long-lasting photodetectors –Process is mature and flexible: demonstrated high processing yield for 3 very different detector designs (resistor chain design, IBD-1 design and photocathode only design) –Capable of producing 20 – 40 6cm photodetectors a year 5

Understand our capability:  We work on every single component of the MCP photo detector  We have good understanding and control of the detector processing  Start from new idea, we can produce working prototype detector in a short time (IBD-1 design is a perfect example)  We can also produce prototype detectors in some quantity for proof of principle experiments 6 This is a unique HEP capability that was built up in the last several years

Scientific opportunities  Cryogenic detector: liquid Argon Time Projection Chambers (LArTPCs), liquid Xenon detector –R&D need: out-of-the-box photodetector that works in cryogenic temperature (for MCP detector: detector structure, window, hermetic sealing, MCP, UV/VUV photocathode), –If successful: direct VUV sensitivity, great time resolution, mm or better position resolution, thin detector profile, potential large area and low cost  Time of Flight, particle ID application in HEP (and Nuclear Physics) experiments: Better time resolution, better QE, better performance in B field, higher rate capability, pad readout –R&D need: optimization of MCP photodetector  Water Cherenkov, (water based) liquid scintillator detector: optical TPC, tracking/vertex reconstruction, Cherenkov and scintillation light separation –R&D need: detector envelope that can work in liquid  Everyone (almost): low cost, large area –The detector technology we developed surely leads to lower cost, and enables large area –R&D need: support commercialization 7

R&D need: cryogenic detector  Structural integrity, mainly the indium seal and frit bond, cause some worry –Work already started: sealed and un-sealed devices ‘dunked’ into liquid nitrogen –4 devices tested, 1 failure (device fell apart due to a hairline crack on the sidewall)  MCP photodetector with glass package DO survive in cryogenic environment  Detector window and sealing –In order to let UV, VUV light get into detector, top window material need to go from borosilicate glass to quartz or MgF 2 –Have tried sealing quartz window in the past  not a problem  Need to try sealing process for MgF 2 window  Cryogenic MCP –Current MCP resistive coating will lose its conductivity at cryogenic temperature  Working on tuning the ALD recipe to bring down resistivity  Also need to verify the ALD secondary emission layer properties at cryogenic temperature 8

R&D need: cryogenic application  UV/VUV photocathode  Photocathode material o CsI cathode is able to cover the UV/VUV spectrum o CsI cathode can be made from solid material via physical vapor deposition o The process is compatible with our current setup  Photocathode electrical contact o Cathode loses conductivity at cryogenic temperature o Electrical contact can be achieved via thin metal coating or thin metal traces  Characterization of UV/VUV cathode o Need UV/VUV monochromator o Need vacuum test environment below 200nm 9 O. Siegmund et al 128 nm

R&D need: cryogenic application  The MCP and VUV cathode are the challenging part of this development  Other part of the R&D (sealing, package) are relatively straight forward for us  Everything fits very well within our unique capability, and we have started…  We view this as a chance to get it done once and for all  we will deliver out-of-the- box working cryogenic photodetectors 10

R&D need: detector optimization  The timing performance (~ 30ps/single p.e., ~10ps/multi p.e. with 20μm pore) of our current 6cm photo detector already outperform commercial products, but there are plenty of things that can make it even better –Optimization of internal detector stack, especially spacer configuration –Using MCP with smaller pore size –Using secondary emission layer with even higher gain (diamond, etc.)  Current photocathode QE is around ~16% (cathode only tube), development of high QE cathode for 6cm device is ongoing –High QE (20% - 35%) achieved with other systems/deposition method –Currently focusing on producing high QE cathode with STPS/effusion cells –Short term goal is 20% - 25%, comparable to current commercial MCP PMT –Implement co-evaporation to shoot for even higher QE 11

R&D need: detector optimization  Pad readout: highly desirable for many applications –Capacitively-coupled pad readout would be a good first try: relatively straightforward to implement, may have rate limitation for some application –Embedded in-detector silicon readout is very attractive but also very challenging  High B field performance –IBD-1 design should work better than the old design (tested by JLab, but not so great) –Need another test with newly produced detector (on-going) –If needed, internal configuration changes should be straightforward  Rate capability –Current design should work with pretty high rate (have some measurements) –If needed, can use MCP with lower resistance 12 These R&D are relatively straightforward for us, but not necessarily for others Since we currently have the capability, should just nail them!

R&D need: detector optimization  New test chamber –A very flexible MCP photodetector test chamber is designed and (partially) built –The internal MCP/spacer stack can be assembled in arbitrary configuration –Allow us to optimize the detector design without building a lot of finished tubes –Need to fix our fast UV laser for the test chamber  Recent bi-alkali photocathode development –Working with cathode only tubes to shorten turn-around time –Implemented better temperature control –Implemented fast cathode cooling after deposition –Working on internal reflector and anti-reflection coating –Need to fix our broken Oxygen plasma generator 13 MCP photodetector stack test chamber

R&D need: working in liquid  This is an area that our detectors can be used (almost) right away  A great chance for us to work with experimental projects –Proof of principle tests –Prototype or small scale experiments –Need to develop a water/liquid proof envelope for the photo detectors  We’ve identified several experiments –ANNIE (Atmospheric Neutrino Neutron Interaction Experiment) Working on installing 1 st 6cm tube from ANL for run 1 (starts in March – April) –TARDIS (Timing and Advanced Reconstruction Done In Scintillator)  We have identified collaborators (Iowa State, UC Davis, UC Berkeley) –Iowa State and UC Davis each received their first 6cm detector from us –UC Davis reported their first test result at ANNIE collaboration meeting –Workshop scheduled in March to discuss collaboration –Possibly support postdoc to spend time at ANL working with us 14

R&D need: working in liquid  One of our major roles is to supplying prototype detectors  Our latest IBD-1 detectors has become highly popular –More and more groups are requesting them (more requests than what we currently have) –6cm form factor fits very well for bench test and proof of principle tests –Commercial LAPPD’s still won’t be available in quantity for some time  Some small scale experiments actually prefer 6cm detector over LAPPD’s  TARDIS –TARDIS needs 40 6cm tubes by 2018 (fits within our capability)  Maintaining some level of 6cm MCP detector production in the next few years would greatly benefit some important project oriented R&D in HEP community  We have designed and started building a new baking/scrubbing chamber to cut down the production time to ~1 tube/week 15 Bake and scrub chamber TARDIS detector 6cm tubes Regular PMTs

R&D need: commercialization  INCOM, Inc. has been our glass capillary array (GSA) supplier and is also the one trying to commercialize the LAPPD –They just finished processing their fully equipped LAPPD #1 –Beside a few minor issues, LAPPD #1 is a big success: good seal, good vacuum –Looks like we can expect commercial LAPPD’s on the market not far in the future!  Argonne (together with SSL/Berkeley, UChicago, etc.) has been supporting INCOM’s effort as much as we can, and will continue to do so –Licensed ALD technology to INCOM –Transferred glass package manufacturing technology –Support of their detector processing –Bi-weekly phone conference with INCOM 16

R&D plan for the MCP photodetector group 17 Cryogenic development MCP detector optimization Develop HEP application Detector processing Support INCOM MCP development Sealing development UV/VUV photocathode development Prototype detector Bi-alkali cathode Optimize performance  IBD-2 design Pad readout Prototype detector Work with ANNIE, TARDIS to implement 6cm tubes Identify and start working with new users 10 tube for users 20 tube for TARDIS (?) Support INCOM commercialization

R&D plan: other activities outside HEP  The MCP detector group is also involved in some application outside HEP, with ANL LDRD and outside support –Compact thermal neutron detector development  GSS Division –EIC detector R&D  Physics Division, BNL, JLab, etc. –3D printing MCP  Material Science Division –Novel photocathode material  Material Science Division –Polarized X-ray detector  NE Division  We take these type of work as a substantial help to maintain our unique capability for future HEP application with resource from outside.  It also help us to bring in resources/capability from outside the HEP division to HEP applications 18

Summary  We have built up a unique MCP photodetector R&D capability at Argonne over the last several years  Now it is the rare (if not the only) chance that our HEP community can custom develop this type of detector for specific application  The next several years would be the time that our HEP community gets benefit from the investment into the MCP photodetector development  We plan to continue the R&D effort in the next several years, in order to maximize the benefit to the HEP community for the investment –Cryogenic application of MCP photodetector –Photodetector optimization: time resolution, QE, pad readout, etc. –Implement 6cm MCP photodetector into small scale experiments –Continue providing sample detectors to potential users –Support INCOM for commercialization 19