arXiv subjects

Benjamin Godfrey

Publications and source records attributed to Benjamin Godfrey.

4 recordsLinked to original sources

arXiv2026

First Light with the Dark100 Array of PANOSETI Telescopes at Palomar Observatory

Dark100 is the first phase of an extensive array of Panoramic SETI (PANOSETI) telescopes at Palomar Observatory, California. PANOSETI telescopes are small, 0.5-m Fresnel lens telescopes instrumented with 1024-pixel silicon photomultiplier (SiPM) cameras. The telescopes were originally designed to search for ultra-fast optical transients, but they also function as cost-effective imaging atmospheric Cherenkov telescopes (IACTs). Dark100 will use seven of these widely separated IACTs to map the ultra-high-energy (UHE) gamma-ray sources on the Galactic Plane at high resolution. Dark100 will also leverage the IACT technique to search for evidence of ultra-heavy dark matter in a mass range that extends beyond 100 TeV. Deployment of the first four telescopes and enclosures was completed in December 2025, and commissioning of the next three is scheduled to finish by the end of 2026. The array has so far collected more than 100 hours of 3-telescope data on sources including the Crab Nebula and Markarian 421. Here we present the current status of Dark100.

astro-ph.IM↗

arXiv2024

New Limit on Dark Photon Kinetic Mixing in the 0.2-1.2 $\boldsymbolμ$eV Mass Range From the Dark E-Field Radio Experiment

We report new limits on the kinetic mixing strength of the dark photon spanning the mass range 0.21 -- 1.24 $μ$eV corresponding to a frequency span of 50 -- 300 MHz. The Dark E-Field Radio experiment is a wide-band search for dark photon dark matter. In this paper we detail changes in calibration and upgrades since our proof-of-concept pilot run. Our detector employs a wide bandwidth E-field antenna moved to multiple positions in a shielded room, a low noise amplifier, wideband ADC, followed by a $2^{24}$-point FFT. An optimal filter searches for signals with Q $\approx10^6$. In nine days of integration, this system is capable of detecting dark photon signals corresponding to $ε$ several orders of magnitude lower than previous limits. We find a 95% exclusion limit on $ε$ over this mass range between $6\times 10^{-15}$ and $6\times 10^{-13}$, tracking the complex resonant mode structure in the shielded room.

hep-ex↗

arXiv2021

Search for Dark Photon Dark Matter: Dark E-Field Radio Pilot Experiment

We are building an experiment to search for dark matter in the form of dark photons in the nano- to milli-eV mass range. This experiment is the electromagnetic dual of magnetic detector dark radio experiments. It is also a frequency-time dual experiment in two ways: We search for a high-Q signal in wide-band data rather than tuning a high-$Q$ resonator, and we measure electric rather than magnetic fields. In this paper we describe a pilot experiment using room temperature electronics which demonstrates feasibility and sets useful limits to the kinetic coupling $ε\sim 10^{-12}$ over 50--300 MHz. With a factor of 2000 increase in real-time spectral coverage, and lower system noise temperature, it will soon be possible to search a wide range of masses at 100 times this sensitivity. We describe the planned experiment in two phases: Phase-I will implement a wide band, 5-million channel, real-time FFT processor over the 30--300 MHz range with a back-end time-domain optimal filter to search for the predicted $Q\sim 10^6$ line using low-noise amplifiers. We have completed spot frequency calibrations using a biconical dipole antenna in a shielded room that extrapolate to a $5 σ$ limit of $ε\sim 10^{-13}$ for the coupling from the dark field, per month of integration. Phase-II will extend the search to 20 GHz using cryogenic preamplifiers and new antennas.

physics.ins-det↗

arXiv2018

On the Evaluation of Silicon Photomultipliers for Use as Photosensors in Liquid Xenon Detectors

Silicon photomultipliers (SiPMs) are potential solid-state alternatives to traditional photomultiplier tubes (PMTs) for single-photon detection. In this paper, we report on evaluating SensL MicroFC-10035-SMT SiPMs for their suitability as PMT replacements. The devices were successfully operated in a liquid-xenon detector, which demonstrates that SiPMs can be used in noble element time projection chambers as photosensors. The devices were also cooled down to 170 K to observe dark count dependence on temperature. No dependencies on the direction of an applied 3.2 kV/cm electric field were observed with respect to dark-count rate, gain, or photon detection efficiency.

physics.ins-det↗