We present advances made in the Large Area Picosecond Photodetector (LAPPD), an 8" $\times$ 8" microchannel plate photomultiplier tube (MCP-PMT), since pilot production was initiated at Incom, Inc. in 2018. The Gen-I LAPPD utilizes a stripline anode for direct charge readout. The novel Gen-II LAPPD employs an internal resistive thin-film which capacitively couples to a customizable external signal readout board, streamlining production. The Gen-II LAPPD, with an active area of 373 cm$^2$, is capable of high single photoelectron (PE) gain of $\sim$10$^7$, low dark rates ($\sim$1 kHz/cm$^2$), single PE timing resolution of $\sim$65 ps, and $\mathcal{O}$(mm) position resolution. Coupled with a UV-grade fused silica window, the LAPPD features a high quantum efficiency (QE) bialkali photocathode of $>$30% with spectral response down to $\sim$165 nm. The LAPPD is an excellent candidate for electromagnetic calorimeter (ECAL) timing layers, photon-based neutrino detectors, high energy collider experiments, medical imaging systems, and nuclear non-proliferation applications.

Conventional PbO-based Microchannel Plates (MCPs) are known to experience large drops in gain as a function of extracted charge, with a particularly large drop known as a “burn-in” period that occurs in the first 1 C/cm2 of extracted charge. Incom has developed ALD-GCA-MCPs that use Atomic Layer Deposition (ALD) to coat Glass Capillary Arrays (GCAs) of a base glass in order to make MCPs. In this way, the electrical and mechanical properties of the MCPs are separated. One advantage of this is that Incom can make MCPs out of various types of glass, such as aluminosilicate, which is substantially free of alkalis that can migrate in the glass matrix and change the electrical properties of the MCPs. This process has enabled Incom, using their proprietary C14 glass, to make MCPs that have much longer device lifetimes. The goal of these experiments was to compare the lifetime performance of Incom MCPs to PbO MCPs, as well as to compare the performance of ALD-GCA-MCPs made out of two types of glass substrates: C14 glass and an alkali-containing C5 glass. The MCP made with C14 glass had a gain of 1E4 at 950 V after 300 C/cm2 extracted charge, and no spatial variations in gain out to at least 23 C/cm2. The MCPs made of C5 glass exhibited imaging defects after 3 C/cm2. The gain of the PbO MCP fell to 1E3 at 950 V after 110 C/cm2.

High Resolution Picosecond Photon Detectors (HRPPDs) are large area Microchannel Plate (MCP) detectors that can provide ultrafast timing and detect single photons with high efficiency and good spatial resolution. This makes them an excellent choice for use in Ring Imaging Cherenkov (RICH) detectors that can be used for particle identification in high energy particle collisions. These devices are being considered for several RICH detectors for the ePIC Experiment at the future Electron Ion Collider (EIC) at Brookhaven National Lab. An effort is currently under way to improve the properties of HRPPDs for RICH applications and to optimize their performance for use at the EIC. This contribution will report on the latest developments with HRPPDs for their use with various types of RICH detectors, and also discuss some of the RICH detector designs for the future ePIC experiment at the EIC.

We have used a subpicosecond laser with an output trigger synched to a 4-GHz oscilloscope sampling at 25 GSa/s to characterize the temporally resolved response of a large area picosecond photodetector (LAPPD) to single photons/photoelectrons. The LAPPD is a large area (20 cm x 20 cm) photosensor with a nanosecond-width time response arising from its underlying multichannel plate photomultiplier tube (MCP-PMT) structure. We used optical filters to attenuate the laser pulse intensity to a single-photon level. LAPPD pulses are nearly identical in shape, particularly for pulses whose peak amplitude is a large multiple of our system's 0.6-mV rms baseline electronic noise. Three waveform timing algorithms were compared in their measurements of the transit time spread (TTS) Gaussian fitted to the distribution of measured single-photoelectron (SPE) pulse times under zero-width laser excitation: 1) a constant fraction algorithm; 2) a pulse centroid timing algorithm; and 3) a pulse model-fitting algorithm. The measured SPE values with the three algorithms are: [79 +/- 17, 67 +/- 15, and 82 +/- 20] ps Gaussian sigma, respectively. The LAPPD provides independent voltage control for its photocathode (PC), and at the entry and entry faces of its chevron pair of MCPs. We found no or minimal change in TTS with PC voltage for pulses >15 mV.

Incom Inc. is developing and commercializing microchannel plate (MCP) electron multiplier devices made from leadfree glass capillary array (GCA) substrates that are functionalized using atomic layer deposition (ALD) thin film coating technology. Notable benefits over conventional lead-oxide based MCP technology are larger MCP size, high and stable gain, low dark counts and gamma-ray sensitivity, improved mechanical and thermal stability, and the unique ability to tune the MCP resistance and electron amplification characteristics over a much wider range and independently from the glass substrate. Incom now routinely produces ALD-GCA-MCPs with 10 and 20 m pore size at MCP dimensions up to 20 cm x 20 cm. ALD-GCA-MCPs are used for photon counting and charged particle detection in analytical instruments, high energy physics, nuclear physics, and space science applications. For future astronomical applications such as LUVOIR, HabEx, and CETUS, large-area, high-performance MCP electron amplifiers are paired with high-performance cross-strip readout systems and integrated into large format (≥ 50 mm sq.) photodetectors operating in the UV and optical regimes. Incom’s large area ALD-MCP-GCA technology is critical for realizing such large format photodetectors. In this paper, we provide a brief update on recent developments addressing the quality of the glass substrate as well as the thermal stability of the MCPs.

1131 Objectives: We are developing novel TOF-PET detector designs by adopting a Large Area Picosecond PhotoDetector (LAPPD), a photosensor technology originally designed for high energy and nuclear physics experiments. The goal is to achieve large detector area with high timing resolution but at low readout channel count, a potential diametric solution to the ongoing silicon photomultiplier based quest with one-one coupling detection scheme. In this work we have measured the fundamental response of a generation-1 (Gen-I) LAPPD device to pairs of coincident Single Photo-Electrons (SPE) using a femtosecond laser. The LAPPD device features a 20x20 cm2 detector area with 28 anode strips with 7 mm anode pitch and a total of 56 readout channels. METHODS: The LAPPD obtains 2D coordinates for each photoelectron in transaxial direction between the strips using charge division of collected multiplied charge clouds at the anode, and in axial direction along the strips using pulse time differences at the two strip ends. This spatial information that can be obtained for SPE (as well as multiple photoelectrons) with our measured LAPPD SPE time response and with independent LAPPD pulse shape and known amplitude distributions, enables accurate system response modeling for design iteration. We have illuminated a Gen-I LAPPD using 230-fs laser pulses at 514 nm and 96 kHz repetition rate. In the optical path between the laser output and LAPPD, we used Thorlabs NB1-K13 mirrors and dual wheel ND filter FW2AND to reduce laser power to single photon level to provide ~35% photoelectron detection efficiency per pulse. We used Thorlabs 50/50 CCM1-BS013 beam splitter to split the laser beam to two spots each 1mm Dia. (by using a 1 mm diameter precision optical pinhole Thorlabs P1000D sitting 2 cm above the LAPPD) illuminating a single LAPPD anode strip. The two spots were at 49 mm separation (7 strips apart) to eliminate potential charge sharing across the strips. In our measurements, we read out four signals, both ends of two anode strips with a 4GHz Tektronix MSO64 oscilloscope running at 25GS/s and 12-bit vertical resolution. We used the scope’s 2-Ch coincidence trigger function, with 5mV thresholds (from one end each of the two illuminated strips), to collect a digitized waveform record for each event. For each of the acquired 100k coincidence triggers, we recorded 1000 data points with 40 ps time binning. Photocathode voltage was set at 100V, while the voltage across both upstream and downstream MCPs in the Chevron pair was set to 900V. Results: Observed pulses were uniform in near-Gaussian shape, with ~1ns FWHM. The time difference jitter between pulses on the two strips was consistent with previously measured SPE time response widths times √2 as expected for two independent photons. SPE time response and widths reflect multiplied charge cloud transit time spread convolved with a uniform pulse shape collected at the stripline anodes, as we observed in previous measurements using the laser’s synced output to trigger the oscilloscope. With coincidence trigger, we measured a pulse arrival time distribution difference (using digital constant fraction discriminators) for coincident single photoelectrons with ~350ps FWHM. The distribution was principally Gaussian, with an expected tail from photoelectrons scattering off the entry MCP before entering a microchannel pore and being multiplied. The time width was nearly independent of LAPPD pulse amplitude for pulses above our fixed 5mV threshold. CONCLUSION: The LAPPD response function measured is specific to this generation of LAPPD, which has 20 microns MCP pores, and where MCP-PMT performance is known to be strongly dependent on pore size and other device design parameters. A 10-micron LAPPD is currently under development, with anticipated improvement of coincidence SPE which will potentially pave the way for large-area TOF-PET detector technology at very modest readout channel count.

Large Area Picosecond Photon Detectors (LAPPDs) are micro-channel plate based photosensors featuring hundreds of square centimeters of sensitive area in a single package and capable of providing timing resolution on the order of 50 ps for single photon detection. However, LAPPDs currently do not exist in finely pixelated 2D readout configurations which, in addition to high-resolution timing, would also provide high spatial resolution required for Ring Imaging CHerenkov (RICH) detectors. One of the recent LAPPD models (Gen II) provides the opportunity to overcome the lack of pixellation by coupling an external readout to the sealed detector itself. The readout plane in this case is a simple printed circuit board (PCB) that can be laid out in a custom application-specific way for 1D or 2D sensitive area pixellation. This allows for a much shorter readout-plane prototyping cycle and provides unprecedented flexibility in choosing an appropriate segmentation that can be optimized for any particular detector need in terms of pad size, orientation, and shape. We fully exploit this feature by designing and testing a variety of readout PCBs with conventional square pads and interleaved anode designs. Data acquired in the lab using a laser system to probe the response of several interleaved and standard pixelated patterns are presented as well as results from a beam test.

Incom Inc. is developing and commercializing a new type of microchannel plate (MCP) electron multiplier, as well as MCP-based photodetectors such as the Large-Area Picosecond Photodetector, LAPPD(TM), and the High-Resolution Picosecond Photodetector, HRPPD. This new class of MCPs is called “ALD-GCA-MCPs” because these are MCPs that are made from glass capillary arrays (GCA) – glass plates with a regular array of hollow glass capillaries – that are functionalized using atomic layer deposition (ALD) thin film coating technology. ALD-GCA-MCPs are a technology advancement that affords MCPs with significantly improved performance, as compared to conventional MCPs. We will provide a brief ALD-GCA-MCP technology overview highlighting the current state of the art of Incom’s ALD-GCA-MCP technology, as well as ongoing developments addressing the GCA glass substrate, the resistive and secondary-electron-emissive ALD coatings, and their implications for detectors used in astronomical applications.

In chronic heart failure (CHF) several studies of iron deficiency (ID) phenomenon were performed. Nevertheless, the data about ID in non-anaemic population are still lacking. 94 stable CHF patients with reduced (<40%) left ventricular ejection fraction (rLVEF) on standard treatment were examined. Only patients with haemoglobin level ≥130 g/L (men) and ≥120 g/L (women) were included. ID criteria: ferritin level <100ng/ml or ferritin 100-299 ng/ml + transferrin saturation <20%. ID was found in 51 (54%) of 94 patients. ID group was characterised by prevalence of New York Heart Assosiation class III-IV patients, lower systolic blood pressure, lower glomerular filtration rate, shorter 6 minutes walking test distance, worse musculus quadriceps femori endurance, worse Minnesota score, higher N-terminal pro b-type Natriuretic Peptide (NT-proBNP), interleukin-6 (IL-6) and citrulline levels. Simultaneously there were no difference in any echocardiographic parameters (LVEF, left ventricular volumes, left atrial size, myocardial mass index). According to Kaplan-Meier analysis, in comparison to non-ID group ID patients demonstrated significantly worse 2-year survival, as well as combined end-point (all-cause mortality/heart failure hospitalisation). In non-anaemic CHF patients and rLVEF, ID is associated with worse functional state, worse quality of life, higher levels of inflammatory (IL-6) and inducible nitric oxide synthase activity (citrulline) markers and with worse 2-year clinical prognosis. Higher level of plasma NT-proBNP in ID patients needs to be explained in the future.

The availability of large-area, economically produced, microchannel plate (MCP) photodetectors with tens of picosecond timing resolution and millimeter level spatial resolution for single photoelectrons are enabling new techniques where fast timing facilitates critical benefits including: more efficient background rejection and high vertex resolution in large scale high energy and nuclear physics (HEP and NP) experiments, particle track directionality information, and precise track reconstruction, as well as separation of Cherenkov and scintillation light. LAP-PDs are now being produced on a routine pilot production basis, and are available to be employed in high energy and nuclear physics, for commercial applications such as in detectors for mass spectrometers, neutron detection for scientific and homeland security (non-proliferation), and for medical imaging time-of-flight positron emission tomography (TOF-PET). In the following, we provide an update on target performance of routinely produced prototype LAPPDs, including the performance of one specific LAPPD which is being evaluated at UC Davis for potential TOF-PET application. Previously obtained preliminary TOF-PET test results, taken at Incom Inc. with an earlier LAPPD, are also discussed.

We report on performance results achieved for recently produced LAPPDs - largest comercially available planar geometry photodetectors based on microchannel plates. These results include electron gains of up to $10^{7}$, low dark noise rates ($\sim$100 Hz/cm$^{2}$ at a gain of $6\cdot10^6$), single photoelectron (PE) timing resolution of $\sim$50 picoseconds RMS (electronics limited), and single photoelectron spatial resolution along and across strips of 3.2mm (electronics limited) and 0.8 mm RMS respectively and high (about 25\% or higher in some units) QE uniform bi-alkali photocathodes. LAPPDs is a good candidate to be employed in neutrino experiments (e.g. ANNIE, WATCHMAN, DUNE), particle collider experiments (e.g. EIC), neutrinoless double-beta decay experiments (e.g. THEIA), medical and nuclear non-proliferation applications.

ALD-GCA-MCPs are a technology advancement that affords microchannel plates (MCPs) with significant performance benefits compared to conventional MCP technology. Incom now routinely produces ALD-GCA-MCPs with dimensions up to 20 cm x 20 cm. Notable advancements and benefits over conventional lead-oxide based MCPs are larger size and higher mechanical stability, high and stable gain (>1e4for single MCP @ 1000 V, stable gain to ≥ 1 C/cm2 extracted charge), low dark counts (≤ 0.05 cts/sec/cm2), ~3x lower gamma-ray sensitivity, and the unique ability to individually customize and control the MCP resistance and secondary electron emission (SEE) amplification characteristics. ALD-GCA-MCPs find application in a variety of photon and charged particle counting applications and are particularly suited for applications that require fast timing, high spatial resolution, radiation hardness, and long detector life times, such as Ion-TOF, electron spectroscopies, and a variety of other analytical instruments. They can also be incorporated into low-power, low-background photodetectors suitable for applications in extreme environments such as remote sensing applications in rugged environments, in space flight instrumentation, as well as in high-energy physics and nuclear physics experiments. In this paper we will provide a brief ALD-GCA-MCP technology overview highlighting recent developments that focused on improving the glass capillary array (GCA) substrate, and their implications for large-area photodetectors and spectrometers used in nuclear and high energy physics, space science, and other sensing applications.

Multi-energy CT with triple x-ray beams and photon-counting-detector CT for simultaneous imaging of two contrast agents: an experimental comparison

Incom Inc. is developing and commercializing a novel type of microchannel plate (MCP) electron multipliers. These new devices are called "ALD-GCA-MCPs" and are made from glass capillary arrays (GCA), glass plates with a regular array of hollow glass capillaries that are functionalized using atomic layer deposition (ALD) thin film coating technology. ALD-GCA-MCPs are a technology advancement that affords MCPs with significantly improved performance, as compared to conventional MCPs. Notable benefits over conventional lead-oxide based MCPs are larger size, high and stable gain, low dark counts and gamma-ray sensitivity, improved mechanical stability, and the unique ability to tune the MCP resistance and electron amplification characteristics over a much wider range and independent from the glass substrate. Incom now routinely produces ALD-GCA-MCPs with 10 and 20 mu m pore size at MCP dimensions up to 20 cm x 20 cm. The MCPs show a number of favorable characteristics, such as 3x lower gamma-ray sensitivity compared to conventional MPCs, low background (< 0.05 cts/s/cm(2)), and stable, high gains (>1x10(4) for single MCP and >1x10(7) for a chevron pair configuration, at 1000V/MCP). ALD-GCA-MCPs find use in a variety of photon counting applications and are particularly suited for charged particle detection that requires high timing and spatial resolution, such as Ion time-of-flight (TOF), electron spectroscopies, analytical and space instruments, and MCP-based photomultipliers such as the Large-Area Picosecond Photodetector (LAPPDTM), which is also being developed by Incom Inc. In this paper, we provide a brief technology overview highlighting the current state of the art of Incom's ALD-GCA-MCP technology, as well as current and future development efforts that address the GCA glass substrate as well as the resistive and electron emissive ALD coatings.

In proton therapy treatment, proton residual energy after transmission through the treatment target may be determined by measuring sub-relativistic transmitted proton time-of-flight velocity and hence the residual energy. We have begun developing this method by conducting proton beam tests using Large Area Picosecond Photon Detectors (LAPPDs) which we have been developing for High Energy and Nuclear Physics Applications. LAPPDs are 20cm x 20cm area Micro Channel Plate Photomultiplier Tubes (MCP-PMTs) with millimeter-scale spatial resolution, good quantum efficiency and outstanding timing resolution of ≤70 picoseconds rms for single photoelectrons. We have constructed a time-of-flight telescope using a pair of LAPPDs at 10 cm separation, and have carried out our first tests of this telescope at the Massachusetts General Hospital's Francis Burr Proton Therapy Center. Treatment protons are sub-relativistic, so precise timing resolution can be combined with paired imaging detectors in a compact configuration while still yielding high accuracy in proton residual energy measurements through proton velocity determination from nearly monoenergetic protons. This can be done either for proton bunches or for individual protons. Tests were performed both in "ionization mode" using only the Microchannel Plates to detect the proton bunch structure and also in "photodetection mode" using nanosecond-decay-time quenched plastic scintillators to excite the photocathode within each of the paired LAPPDs. Data acquisition was performed using a remotely operated oscilloscope in our first beam test, and using 5Gsps DRS4 Evaluation Board waveform digitizers in our second test, in each case reading out both ends of single microstrips from among the 30 within an LAPPD. First results for this method and future plans are presented.

We report performance results achieved for fully functional sealed Large Area Picosecond Photodetectors (LAPPD (TM)) in tests performed at Incom Inc., as well as independent test results reported by our early adopters. The LAPPD is a microchannel plate (MCP) based large area picosecond photodetector, capable of imaging with single-photon sensitivity at high spatial and temporal resolutions in a hermetic package. The LAPPD has an active area of 350 square centimeters in an all-glass hermetic package with a fused silica window and bottom plate and sidewalls made of borosilicate float glass. Signals are generated by a bi-alkali Na2KSb photocathode and amplified with a stacked chevron pair of MCPs produced by applying resistive and emissive atomic layer deposition coatings to glass capillary array (GCA) substrates. Signals are collected on RF stripline anodes applied to the bottom plates which exit the detector via pin-free hermetic seals under the side walls. LAPPD test and performance results for product produced and delivered to early adopter customers during the first half of 2018 are reviewed. These results include electron gains >= 7.5 x 10(6) @ 850/950 V (entry/exit MCP), low dark noise rates (22 Cts/s/cm(2)), single photoelectron (PE) timing resolution of 64 picoseconds RMS, and single photoelectron spatial resolution along and across strips of 2.8 mm and 1.3 mm RMS respectively. Many of these devices also had very high QE photocathodes that were uniform over the full 195 mm x 195 mm window active area (LAPPD #15 QE% @ 365 nm Max/Avg/Min = 25.8/22.3 +/- 3/15.7). An update is also provided of developments that enable capacitive signal coupling from the detector to application specific pads or stripline readout patterns deployed on printed circuit boards positioned beneath the file, outside of the vacuum package. We conclude with examples of how sensors offering picosecond timing, in diverse applications can bring transformative change to detector technology and applications in future experiments.

Microchannel Plate (MCP) detectors combine high spatial resolution (<20 μm FWHM), photon counting (noiseless) imaging in a robust, radiation-hard package that is scalable to very large formats (>10 cm & > 4k x 4k pixels). They operate at room temperature with very low dark count rate and provide event timing at the level of 10 ps. Advances in MCP technology offer potential performance improvements in quantum efficiency, long term stability, environmental stability, image quality and spatial resolution. These are being realized with cross strip (XS) readout techniques and high performance encoding electronics in concert with atomic layer deposited (ALD) microchannel plate technologies. Specific objectives are to make sensors with large areas (up to 400 cm2) with spatial resolutions of <20 μm FWHM and timing resolutions of <100 ps for dynamic imaging. Photocathodes for the UV and visible regimes are being investigated which also allow reduction of the red response of classical multialkali photocathodes. Borosilicate MCPs processed with ALD techniques are providing large formats (20 cm) with reduced background levels, improved image fidelity and uniformity. High resolution cross strip anodes and electronics for 50mm and 100 mm detectors have been demonstrated and high-performance ASIC versions of the electronics are in development. Planacon sealed tube devices with 50 mm format provide a good test vehicle for ALD MCPs and XS anodes are already showing promising results.

Incom, Inc. is now producing commercially available Large Area Picosecond Photo-Detectors (LAPPDT) usable in applications by early adopters. The first generation LAPPD (TM) is an all-glass 230 x 220 x 22 mm(3) flat panel photodetector with a chevron stack of glass capillary array microchannel plates functionalized by atomic layer deposition, a semitransparent bi-alkali photocathode, and a strip-line anode. The photodetector is being optimized for applications requiring picosecond timing and millimeter spatial resolution and has achieved single photoelectron (PE) timing resolutions of sigma <= 52 ps. Typical performance metrics include electron gains of 10(7) at 1 kV per MCP, low dark noise rates (15-30 Hz/cm(2) at moderate gains), single PE spatial response along and across strips of 1.8 mm and 0.76 mm respectively and quantum efficiencies that are typically >= 20% at 365 nm. Changes to the "baseline" LAPPD (TM) are under development to optimize the photodetector for applications requiring very high spatial resolutions.

Incom is reporting on success in its DOE SBIR Phase I feasibility demonstration of our ability to optimize and characterize the magnetic field insensitivity of Large Area Picosecond Photon Detectors (LAPPDs) which we manufacture, this was accomplished principally by decreasing MCP pore sizes. LAPPDs are cost-effective ultra-high time precision imaging quantum photodetectors that incorporate Incom’s unique large-area ALD- (Atomic Layer Deposition) GCA- (Glass Capillary Array) MCPs (Microchannel Plates). Several applications of LAPPDs, including for potential upgrades to existing DoE NP detectors or as part of proposed designs for future DoE NP experiments (including at the future EIC Electron Ion Collider) will require LAPPD operation in strong magnetic fields. We are improving and verifying the performance of LAPPDs in strong magnetic fields both by modifying their internal construction and most importantly by modifying their constituents by using smaller-pore MCPs; we and others have shown that this improves magnetic field insensitivity in MCP-PMTs like our LAPPD. We have begun a series of magnetic field tests at Argonne National Laboratory on 6 x 6cm MCP-PMTs constructed at ANL using Incom MCPs, and on 20 x 20cm LAPPDs constructed at Incom again using Incom MCPs, each in a series of devices containing MCPs of ever smaller pore diameters, from 20μ to 10μ to 5μ; in addition to improving magnetic field insensitivity, smaller pores will improve LAPPD timing and thus benefit physics performance in future DoE NP detectors, including at the EIC.