arXiv subjects

D. Frolov

Publications and source records attributed to D. Frolov.

11 recordsLinked to original sources

arXiv2023

New Exclusion Limit for Dark Photons from an SRF Cavity-Based Search (Dark SRF)

We conduct the first ``light-shining-through-wall" (LSW) search for dark photons using two state-of-the-art high quality-factor superconducting radio frequency (SRF) cavities and report the results of its pathfinder run. Our new experimental setup enables improvements in sensitivity over previous searches and covers new dark photon parameter space. We design delicate calibration and measurement protocols to utilize the high-$Q$ setup at Dark SRF. Using cavities operating at $1.3 \ \text{GHz}$, we establish a new exclusion limit for kinetic mixing as small as {$ε= 1.6\times 10^{-9}$} and provide the world's best constraints on dark photons in the $2.1\times 10^{-7} \ \text{eV} - 5.7\times10^{-6} \ \text{eV}$ mass range. Our result is the first proof-of-concept for the enabling role of SRF cavities in LSW setups, with ample opportunities for further improvements. In addition, our data sets a competitive lab-based limit on the Standard Model photon mass by searching for longitudinal photon polarization.

hep-ex↗

arXiv2022

Disentangling the sources of ionizing radiation in superconducting qubits

Radioactivity was recently discovered as a source of decoherence and correlated errors for the real-world implementation of superconducting quantum processors. In this work, we measure levels of radioactivity present in a typical laboratory environment (from muons, neutrons, and gamma's emitted by naturally occurring radioactive isotopes) and in the most commonly used materials for the assembly and operation of state-of-the-art superconducting qubits. We develop a GEANT-4 based simulation to predict the rate of impacts and the amount of energy released in a qubit chip from each of the mentioned sources. We finally propose mitigation strategies for the operation of next-generation qubits in a radio-pure environment.

quant-ph↗

arXiv2022

High quality superconducting Nb co-planar resonators on sapphire substrate

We present measurements and simulations of superconducting Nb co-planar waveguide resonators on sapphire substrate down to millikelvin temperature range with different readout powers. In the high temperature regime, we demonstrate that the Nb film residual surface resistance is comparable to that observed in the ultra-high quality, bulk Nb 3D superconducting radio frequency cavities while the resonator quality is dominated by the BCS thermally excited quasiparticles. At low temperature both the resonator quality factor and frequency can be well explained using the two-level system models. Through the energy participation ratio simulations, we find that the two-level system loss tangent is $\sim 10^{-2}$, which agrees quite well with similar studies performed on the Nb 3D cavities.

physics.app-ph↗

arXiv2020

Intrinsic Quality Factor Extraction of Multi-Port Cavity with Arbitrary Coupling

We derived S-parameter based expressions for the intrinsic quality factor of an arbitrary coupled multiport microwave cavity and non-ideal test fixture. Practical accuracy limitations of the obtained expressions specifically for superconducting accelerator cavities were evaluated both analytically and with the simulation software. The resulting formulas can be used to extract intrinsic quality factor of normal conducting and superconducting cavities directly from calibrated S-parameter measurements.

physics.acc-ph↗

arXiv2019

Three-dimensional superconducting resonators at $T < 20$ mK with the photon lifetime up to $τ=2$ seconds

Very high quality factor superconducting radio frequency cavities developed for accelerators can enable fundamental physics searches with orders of magnitude higher sensitivity, as well as offer a path to a 1000-fold increase in the achievable coherence times for cavity-stored quantum states in the 3D circuit QED architecture. Here we report the first measurements of multiple accelerator cavities of $f_0=$1.3, 2.6, 5 GHz resonant frequencies down to temperatures of about 10~mK and field levels down to a few photons, which reveal record high photon lifetimes up to 2 seconds, while also further exposing the role of the two level systems (TLS) in the niobium oxide. We also demonstrate how the TLS contribution can be greatly suppressed by the vacuum heat treatments at 340-450$^\circ$C.

quant-ph↗

arXiv2019

Experience with Long-pulse Operation of the PIP2IT Warm Front End

The warm front end of the PIP2IT accelerator, assem-bled and commissioned at Fermilab, consists of a 15 mA DC, 30 keV H- ion source, a 2 m long Low Energy Beam Transport (LEBT) line, and a 2.1 MeV, 162.5 MHz CW RFQ, followed by a 10 m long Medium Energy Beam Transport (MEBT) line. A part of the commissioning efforts involves operation with the average beam power emulating the operation of the proposed PIP-II accelera-tor, which will have a duty factor of 1.1% or above. The maximum achieved power is 5 kW (2.1 MeV x 5 mA x 25 ms x 20 Hz). This paper describes the difficulties encoun-tered and some of the solutions that were implemented.

physics.acc-ph↗

arXiv2018

High Burst Rate Charging System for the Lithium Lens Power Supply

Two pulsed power systems have been upgraded for the g-2 experiment at Fermilab. The Pbar Lithium Lens supply previously ran with a half sine pulsed current of 75 kA peak, 400 us duration and a repetition rate of 0.45 pps. For the g-2 experiment, the peak current was reduced to 25 kA, but the repetition rate was increased to an average of 12 pps. Furthermore, the pulses come in a burst of 8 with 10 ms between each of 8 pulses and then a delay until the next burst. The charging rate has gone up by a factor of 20 due to the burst speed. A major challenge for the upgrade was to charge the capacitor bank while keeping the power line loading and charging supply cost to a reasonable level. This paper will discuss how those issues were solved and results from the operational system.

physics.acc-ph↗

arXiv2018

First Performance Results Of The PIP2IT MEBT 200 Ohm Kicker Prototype

The PIP-II project is a program to upgrade the Fermilab accelerator complex. The PIP-II linac includes a 2.1 MeV Medium Energy Beam Transport (MEBT) section that incorporates a unique chopping system to perform arbitrary, bunch-by-bunch removal of 162.5 MHz structured beam. The MEBT chopping system will consist of two identical kickers working together and a beam absorber. One design of two having been proposed has been a 200 Ohm characteristic impedance traveling wave dual-helix kicker driven with custom designed high-speed switches. This paper reports on the first performance results of one prototype kicker built, installed and tested with beam at the PIP-II Injector Test (PIP2IT) facility. The helix deflector design details are discussed. The electrical performance of the high-speed switch driver operating at 500 V bias is presented. Tests performed were chopping beam at 81.25 MHz for microseconds as well as with a truly arbitrary pattern for 550 $μ$s bursts having a 45 MHz average switching rate and repeating at 20 Hz.

physics.acc-ph↗

arXiv2018

PIP-II Injector Test Warm Front End: Commissioning Update

The Warm Front End (WFE) of the Proton Improvement Plan II Injector Test at Fermilab has been constructed to its full length. It includes a 15-mA DC, 30-keV H- ion source, a 2 m-long Low Energy Beam Transport (LEBT) with a switching dipole magnet, a 2.1 MeV CW RFQ, followed by a Medium Energy Beam Transport (MEBT) with various diagnostics and a dump. This report presents the commissioning status, focusing on beam measurements in the MEBT. In particular, a beam with the parameters required for injection into the Booster (5 mA, 0.55 ms macro-pulse at 20 Hz) was transported through the WFE.

physics.acc-ph↗

arXiv2018

Status of the warm front end of PIP-II injector test

The Proton Improvement Plan II (PIP-II) at Fermilab is a program of upgrades to the injection complex. At its core is the design and construction of a CW compatible, pulsed H- SRF linac. To validate the concept of the front-end of such machine, a test accelerator known as PIP-II Injector Test (PIP2IT) is under construction. It includes a 10 mA DC, 30 keV H- ion source, a 2 m-long Low Energy Beam Transport (LEBT), a 2.1 MeV CWRFQ, followed by a Medium Energy Beam Transport (MEBT) that feeds the first of 2 cryomodules increasing the beam energy to about 25 MeV, and a High Energy Beam Transport section (HEBT) that takes the beam to a dump. The ion source, LEBT, RFQ, and initial version of the MEBT have been built, installed, and commissioned. This report presents the overall status of the warm front end.

physics.acc-ph↗

arXiv2017

A 600 Volt Multi-Stage, High Repetition Rate GaN FET Switch

Using recently available GaN FETs, a 600 Volt three-stage, multi-FET switch has been developed having 2 nanosecond rise time driving a 200 Ohm load with the potential of approaching 30 MHz average switching rates. Possible applications include driving particle beam choppers kicking bunch-by-bunch and beam deflectors where the rise time needs to be custom tailored. This paper reports on the engineering issues addressed, the design approach taken and some performance results of this switch.

physics.acc-ph↗