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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

AC-LGADs Fermilab front-end electronics characterization

Here, we characterized the front-end electronics used to process high-frequency signals from low-gain avalanche diodes (LGADs) at the Fermilab Test Beam Facility. LGADs are silicon detectors employed for charged particle tracking, offering exceptional spatial and temporal resolution. The purpose of this characterization was to understand how the time resolution is influenced by the front-end electronics. To achieve this, we developed a setup capable of generating input signals with varying amplitudes. The output results demonstrated that signal processing by the front-end electronics plays a crucial role in enhancing time resolution. We showed that the time resolution achieved by the FEE board is better than 2 p s at the 1 σ level.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Performance of an X-γ ray detection system based on a thick silicon LGAD

We present the performance of a X-γ ray detection systems based on a 300 µm thick silicon low-gain avalanche diode (LGAD) and of an equivalent Diode structure without the gain layer, read-out by a custom-made low-noise charge amplifier. For the LGAD structure, the multiplication gains M s from 10.2 to 19.3 are measured, and the Equivalent Noise Charge (ENC) components have been studied in detail. As expected, a significant reduction of the white and 1/f voltage series and dielectric ENC components is observed with increasing gain, shortening the optimum peaking time to τ = 0.4÷8 μs depending on the gain value, with respect to the standard diode, while the parallel ENC component increases proportionally to the gain up to M s = 15. Setting the gain M s = 12.7, a minimum ENC = 34.5 electrons r.m.s. (298 eV FWHM) at τ = 1 μs is found. However, the electronic noise, evaluated on the pulser FWHM, is found to only marginally contribute to the width of the spectral lines of a radioactive source, which are dominated instead by the statistical noise of the charge multiplication within the LGAD structure. The spectral lines' excess width is found to be proportional to the signal multiplication gain M s and increases with the energy of the photons. A minimum line width of 850 eV FWHM at 13.9 keV is measured at room temperature, τ = 2 μs and a gain M s = 10.2.

47 OTHER INSTRUMENTATION↗
DOE OSTI2025

Precision Timing in CMS at the HL-LHC: Current Progress on Validation and Production

During the High Luminosity phase of LHC, up to 200 proton-proton collisions per bunch crossing will bring severe challenges for event reconstruction. To mitigate pileup effects, an extended upgrade program of the CMS experiment is expected. Among which, a new timing layer, the MIP Timing Detector (MTD), will be integrated between the tracker and the calorimeters. With a time resolution of 30-60 ps, the MTD will enable 4D vertexing, bringing significant improvements in track-to-vertex association and object identification. The MTD is composed of two subsystems based on different technologies: the Barrel Timing Layer (BTL) consists of LYSO:Ce scintillating crystals readout by SiPMs, and the Endcap Timing Layer (ETL) is made of Low-Gain Avalanche Diodes. The BTL is currently under production, while ETL sensor prototyping and validation are ongoing. Recent system tests have confirmed the performance of the full acquisition chain. This talk will provide an overview of the MTD design, along with the physics motivation, and the current status of BTL construction and ETL development.

Safdari, Murtaza [Fermilab] (ORCID:000000018323731↗
DOE OSTI2026

CMS Endcap Timing Layer: System Validation and Assembly

The High-Luminosity Large Hadron Collider (HL-LHC) will operate at unprecedented luminosities, resulting in up to 200 simultaneous interactions per bunch crossing. To mitigate the resulting pileup challenges, the CMS experiment is implementing the MIP Timing Detector (MTD), designed to provide precise timing information with a resolution of 30 – 40 picoseconds per track. The MTD consists of the Barrel Timing Layer (BTL) and the Endcap Timing Layer (ETL), each optimized for different regions of the detector. The ETL, comprising two double-sided disks, utilizes Low-Gain Avalanche Diode (LGAD) sensors coupled with the Endcap Timing Readout Chip (ETROC) to achieve high-precision timing measurements in the forward region. Significant progress has been made toward the realization of the ETL through extensive system-level validation of the ETROC readout chain and the development of scalable module assembly procedures. This presentation will provide a comprehensive overview of the ETL and highlight recent advances in system validation and module assembly, emphasizing their roles in ensuring the detector readiness for HL-LHC operation.

Lee, Dongyub [Kyungpook Natl. U.] (ORCID:000000034↗
DOE OSTI2025

Characterization of 4H-SiC Low Gain Avalanche Detectors (LGADs)

4H-SiC Low Gain Avalanche Detectors (LGADs) have been fabricated and characterized. The devices employ a circular mesa design with low-resistivity contacts and an SiO 2 passivation layer. The I–V and C–V characteristics of the 4H-SiC LGADs are compared with complementary 4H-SiC PiN diodes to confirm a high breakdown voltage and low leakage current. Both LGADs and PiN diodes were irradiated with alpha particles from a $^{210}_{84}$Po source. The charge collected by each device was compared, and it was observed that low-gain charge carrier multiplication is achieved in the 4H-SiC LGAD.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Fabrication of 4H-SiC Low Gain Avalanche Detectors (LGADs)

Low gain avalanche detectors (LGADs) offer high temporal resolution for high energy particle detection, which is critical for next generation experiments in hadron colliders. While silicon LGADs (Si-LGADs) have rapidly matured in the last decade, research into silicon carbide (SiC) LGADs has only recently begun. By accounting for fundamental differences in material properties and fabrication processes, we present a prototype device design and process flow for 4H-SiC LGADs with etch-based isolation. Critical steps of the process flow and their results are discussed, including plasma etching, passivation, and the formation of low resistivity contacts. Electrical characterization (I-V, C-V) shows sufficient depletion of the device structure to demonstrate low-gain charge carrier multiplication.

High Energy Physics↗