Engineering topics
Wilder, M.
Publications and source records attributed to Wilder, M..
Toward an integrated multi-gigahertz ionizing particle diagnostic
Needs arising at both current and future accelerator facilities call for the development of radiation-hardened position-sensing diagnostics that can operate with multi-GHz repetition rates. Such instruments are likely to also have applications in the diagnosis of rapid plasma behavior. Here, building on the recent work of our Advanced Accelerator Diagnostics Collaboration, we are exploring the development of integrated multi-GHz ionizing particle detection systems based on chemical-vapor deposition diamond sensors, with the initial goal of producing a quadrant detector that can determine the intensity and centroid position of a particle beam at a repetition rate between 5 and 10 GHz. Results from our initial high-speed characterization work are presented, including those from a single-channel sensor with a GHz response. Approaches to achieving multi-GHz (5–10 GHz) rate capability, including the design of a dedicated Application Specific Integrated Circuit and the use of 3D RF-solver computer aided design software, are presented and discussed in more detail. 3D RF simulations suggest clean pulses of duration less than 250 ps (FWHM less than 125 ps) can be achieved with the approaches developed by this work.
A first look at AS-ROC: a Si-Ge integrated chip readout for fast timing
Abstract Advances in timing detector technology require new specialized readout electronics. Applications demand below 10 ps time of arrival resolution and low power for a low repetition rate. A possible path to achieve O(10 ps) time resolution is an integrated chip using Silicon Germanium (SiGe) technology. Using DoE SBIR funding, Anadyne, Inc., in collaboration with UC Santa Cruz, has developed a prototype SiGe front-end readout chip optimized for low power and timing resolution. Two versions of the chip were produced with performance in simulation: a more power version with 10 ps resolution at 5 fC with 1.1 mW/channel, and a less power version with 10 ps resolution at 8 fC with 0.6 mW/channel.The chip was produced at Tower Semiconductor with 350 nm technology. The ASIC from the prototype run shows good performance: a rise time of 0.7–1 ns and 25 mV per fC response with RMS noise <1 mV. Simulation and results from the prototype will be reported in this paper.
Development of diamond-based diagnostics for next-generation XFELs
The composition and performance of three different diamond sensor based pass-through diagnostics are presented. A position-sensitive quadrant sensor was designed and characterized using the XPP beam at the SLAC LCLS, demonstrating a generated-charge resolution of 0.025 pC and a position sensitivity of 2 μm, measurable pulse-by-pulse at a repetition rate of up to 50 MHz. A compact signal path capable of repetition rates up to 1 GHz was used to characterize the charge collection properties of diamond sensors as a function of the density of electron-hole pairs created within the sensor, finding a limit of approximately 10 16 electron-hole pairs per cm 3 beyond which the collection efficiency and time began to degrade. Finally, a proposed scheme for measuring ionizing radiation at multi-GHz rates is presented, along with results preliminarily demonstrating signal transport capability in excess of 5 GHz.
First test results of the trans-impedance amplifier stage of the ultra-fast HPSoC ASIC
Abstract We present the first results from the HPSoC ASIC designed for readout of Ultra-fast Silicon Detectors. The 4-channel ASIC manufactured in 65 nm CMOS by TSMC has been optimized for 50 μm thick AC-LGAD. The evaluation of the analog front end with β-particles impinging on 3 × 3 AC-LGAD arrays (500 μm pitch, 200 × 200 μm 2 metal) confirms a fast output rise time of 600 ps and good timing performance with a jitter of 45 ps. Further calibration experiments and TCT laser studies indicate some gain limitations that are being investigated and are driving the design of the second-generation pre-amplification stages to reach a jitter of 15 ps.
Development of a Pass-Through Diagnostic for Next-Generation XFELs Using Diamond Sensors
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Use of diamond sensors for a high-flux, high-rate X-ray pass-through diagnostic
X-ray free-electron lasers (XFELs) deliver pulses of coherent X-rays on the femtosecond time scale, with potentially high repetition rates. While XFELs provide high peak intensities, both the intensity and the centroid of the beam fluctuate strongly on a pulse-to-pulse basis, motivating high-rate beam diagnostics that operate over a large dynamic range. The fast drift velocity, low X-ray absorption and high radiation tolerance properties of chemical vapour deposition diamonds make these crystals a promising candidate material for developing a fast (multi-GHz) pass-through diagnostic for the next generation of XFELs. A new approach to the design of a diamond sensor signal path is presented, along with associated characterization studies performed in the XPP endstation of the LINAC Coherent Light Source (LCLS) at SLAC. Qualitative charge collection profiles (collected charge versus time) are presented and compared with those from a commercially available detector. Quantitative results on the charge collection efficiency and signal collection times are presented over a range of approximately four orders of magnitude in the generated electron–hole plasma density.
Digital switch boards for IV and CV measurements of large-array Low Gain Avalanche Detectors
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Effect of deep gain layer and Carbon infusion on LGAD radiation hardness
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Radiation hardness of the low gain avalanche diodes developed by NDL and IHEP in China
This paper presents a study on the radiation hardness of low gain avalanche detector (LGAD) developed by the Novel Device Laboratory (NDL) in Beijing and the Institute of High Energy Physics (IHEP) of Chinese Academy of Sciences, in the context of an upgrade project of the ATLAS detector for the high luminosity phase of LHC. NDL LGAD sensors with different layouts, epitaxial resistivity and doping profile were irradiated up to 1.02 × 10 15 n eq /cm 2 by 70 MeV protons at Cyclotron and Radioisotope Center (CYRIC). The timing resolution of NDL LGAD sensors reached 50 ps and the collected charge reached 3 - 4 fC after irradiation.
Experimental Study of Acceptor Removal in UFSD
The performance of the Ultra-Fast Silicon Detectors (UFSD) after irradiation with neutrons and protons is compromised by the removal of acceptors in the thin layer below the junction responsible for the gain. In this study, the effect is tested both with capacitance–voltage, C–V, measurements of the doping concentration and with measurements of charge collection, CC, using charged particles. We find a perfect linear correlation between the bias voltage to deplete the gain layer determined with C–V and the bias voltage to collect a defined charge, measured with charge collection. An example for the usefulness of this correlation is presented.
Layout and performance of HPK prototype LGAD sensors for the High-Granularity Timing Detector
The High-Granularity Timing Detector is a detector proposed for the ATLAS Phase II upgrade. The detector, based on the Low-Gain Avalanche Detector (LGAD) technology, will cover the pseudo-rapidity region of 2.4 < |n| < 4.0 with two end caps on each side and a total area of 6.4 m 2 . The timing performance can be improved by implanting an internal gain layer that can produce signals with a fast rising edge. It significantly improves the signal-to-noise ratio. The required average timing resolution per track for a minimum ionizing particle is 30 ps at the start and 50 ps at the end of the HL-LHC operation. This is achieved with several layers of LGAD. The innermost region of the detector would accumulate a 1MeV neutron-equivalent fluence up to 2.5 10 15 n eq /cm 2 including a safety factor of 1.5 before being replaced during the scheduled shutdowns. The addition of this new detector is expected to play an important role in the mitigation of high pile-ups at the HL-LHC. The layout and performance of the various versions of LGAD prototypes produced by Hamamatsu (HPK) have been studied by the ATLAS Collaboration. The breakdown voltages, depletion voltages, inter-pad gaps, collected charge as well as the time resolution have been measured and the production yield of large size sensors has been evaluated.
Radiation campaign of HPK prototype LGAD sensors for the High-Granularity Timing Detector (HGTD)
In this work, we report on the results of a radiation campaign with neutrons and protons of Low Gain Avalanche Detectors (LGAD) produced by Hamamatsu (HPK) as prototypes for the High-Granularity Timing Detector (HGTD) in ATLAS. Sensors with an active thickness of were irradiated in steps of roughly 2 up to a fluence of 3. As a function of the fluence, the collected charge and time resolution of the irradiated sensors will be reported for operation at °C.
Conformal Ablative Thermal Protection Systems (CA-TPS) for Venus and Saturn Backshells
This poster provides an overview of the work performed to date on the Conformal Ablative TPS (CA-TPS) element of the TPSM project out of GCDP. Under this element, NASA is developing improved ablative TPS materials based on flexible felt for reinforcement rather than rigid reinforcements. By replacing the reinforcements with felt, the resulting materials have much higher strain-to-failure and are much lower in thermal conductivity than their rigid counterparts. These characteristics should allow for larger tile sizes, direct bonding to aeroshells and even lower weight TPS. The conformal phenolic impregnated carbon felt (C-PICA) is a candidate for backshell TPS for both Venus and Saturn entry vehicles.
Conformal Ablative Thermal Protection Systems (CA-TPS) for Venus and Saturn Backshells
The new conformal ablator C-PICA, which was developed under STMD GCD, is an optimal candidate for use on the backshells for high velocity entry vehicles at both Venus and Saturn. The material has been tested at heat fluxes up to 400 Wcm2 in shear and over 1800 Wcm2 and 1.5 atm in stagnation with good results. C-PICA has similar density to PICA, but shows half the thermal penetration and similar recession at the same conditions, allowing for a lighter weight TPS to be flown. This poster for VEXAG will show the progress made in the development of the material and why it should be considered for use.
Ferredoxin of clostridium thermosaccharolyticum
Electron transfer by energy producing biochemical fuel cell reactions