Dr
Gianpaolo Carosi
(Lawrence Livermore National Laboratory)
25/08/2015, 09:10
In this talk I will present an overview of the axion dark matter haloscopes that use microwave cavities to resonantly enhance the conversion rate of axions to potentially detectable levels. I will layout the number of design challenges facing experimental efforts moving forward.
25/08/2015, 09:40
Here we will present a historical context for the design considerations that lead to the ADMX cavity system from Phase 0 - Phase I.
Dr
Frank Krawczyk
(Los Alamos National Laboratory)
25/08/2015, 09:50
The numerical design chapter of the class addresses two topics: (1) Numerical Methods that include resonator design basics, introduction to Finite Difference, Finite Element and other methods, and (2) Introduction to Simulation Software that covers 2D and 3D software tools and their applicability, concepts for problem descriptions, interaction with particles, couplers, mechanical and thermal...
Daniel Bowring
(Fermilab)
25/08/2015, 11:10
RF codes such as Comsol and CST Microwave Studio are powerful tools but they have some limitations. Most notably, simulation throughput is limited by the availability of expensive (and therefore typically scarce) solver seats. Furthermore, high-fidelity geometry meshing may be difficult.
SLAC has developed ACE3P, a 3D parallel code for RF structure simulation that runs on the National...
Prof.
Jonas Zmuidzinas
(California Institute of Technology)
25/08/2015, 13:00
Superconducting microresonators have attracted substantial attention over the past fifteen years due to a number of applications including photon detection, particle detection, and quantum devices. Our understanding of the behavior of these devices has advanced substantially during this period, particularly with regard to the influence of two-level systems on the dissipation and noise observed...
Nick Materise
(Lawrence Livermore National Laboratory)
25/08/2015, 14:00
Over the last decade, superconducting qubits have emerged as strong candidates for a scalable quantum computing architecture. These devices deliver coherence times approaching milliseconds and basic coherent quantum logic operations have been demonstrated. First order models for superconducting qubits follow lumped circuit element representations, capturing a large portion of their behavior...
Dr
Matt Horsley
(LLNL)
25/08/2015, 14:30
We will present initial simulation work for microstrip resonators at LLNL.
Mr
Sean O'Kelley
(UC Berkeley)
25/08/2015, 15:10
Here we will overview the SQUID amplifier that has been developed for the ADMX experiment.
Mr
Christian Boutan
(University of Washington)
25/08/2015, 16:10
The Axion Dark Matter eXperiment (ADMX) searches for dark-matter axions by looking for their resonant conversion to microwave photons in a strong magnetic field. In the event that ADMX rules out axions in the 500MHz - 2GHz frequency range, new technologies and cavity geometries will need to be explored to find higher mass axions. ADMX Sidecar is a higher frequency pathfinder experiment that...
25/08/2015, 16:30
Here we will present work on a prototype rotary piezoelectric drive system to adjust tuning rods in the ADMX experiment.
Dr
Harry Themann
(Center for Axion and Precision Physics)
26/08/2015, 09:00
I will present our experiences with developing expertise at cavity design. We were given a chance to run parasitically in an 8T magnet with a 60mm bore. This drove our choice of frequency regime. Because of the fixed geometry of the refrigerator and magnet we were required to have all mechanisms and actuators in close proximity to the dilution refrigerator and in a fringe field of 100-300G. We...
Prof.
Karl van Bibber
(UC Berkeley)
26/08/2015, 09:35
Here we will present an overview of the ADMX-HF experiment at Yale University and discuss the lessons learned in the development of a 4-6 GHz microwave cavity which has recently gone through its first commissioning data taking.
Gray Rybka
(University of Washington)
26/08/2015, 10:30
Overview and progress of the open cavity resonator concept.
Dr
Stephen Parker
(The University of Western Australia)
26/08/2015, 11:05
The cross-spectrum of two measurements rejects uncorrelated signals, while retaining those that are correlated. Here we present some fundamental concepts of cross-correlation measurements and how they can be applied to axion cavity searches. One technique allows for improved resolution when observing the intrinsic thermal noise of cavities by rejecting uncorrelated amplifier noise. A different...
Prof.
Michael Tobar
(The University of Western Australia)
26/08/2015, 12:40
At the University of Western Australia we have a long history of developing high-Q cavities and transducers at microwave frequencies for applications for precision measurement, frequency standards, quantum information applications and testing fundamental physics. The latter includes hidden sector photon and axion experiments. Types of resonators include high-Q dielectric whispering gallery...
Dr
Gianpaolo Carosi
(Lawrence Livermore National Laboratory)
26/08/2015, 13:35
Here we outline the concept of using reactive endcaps to lower the frequency of a cylindrical cavity.
Ms
Nicole Crisosto
(University of Florida ADMX)
26/08/2015, 13:45
A status update of prototype testing for LC circuit based axion searches will be presented. This will include initial results for various inductor geometries and tuning mechanisms.
Akash Dixit
(University of Chicago)
26/08/2015, 14:05
Simulations and initial measurements of a reetnrant cavity designed to explore lower frequencies in a fixed magnet bore volume.
Katsuya Yonehara
(Fermilab)
26/08/2015, 14:45
Improved aluminum refining techniques now provide high-quality, cost-effective high-purity aluminum samples. The high-purity aluminum will be better resonator material than copper because of its extremely low resistivity and high thermal conductivity at cryogenic temperature in strong magnetic fields. We will show material properties of high-purity aluminum and demonstrate possible improvement...
Daniel Bowring
(Fermilab)
26/08/2015, 15:15
This overview will outline the motivation and concepts behind superconducting radio-frequency microwave cavities, primarily in the context of accelerator cavities.
Sam Posen
(Fermilab)
26/08/2015, 15:45
This talk will discuss the ultimate limitations for high Q0 operation of SRF cavities, including theoretical predictions and experimental measurements. Various SRF materials are considered and realistic expectations for maximum magnetic fields on the walls of the cavity are presented.
Maria Simanovskaia
(UC Berkeley)
26/08/2015, 16:15
Here we will outline an RF sputtering system that has recently been installed at UC Berkeley with the goal of developing superconducting thin film cavities for axion searches.
David Tanner
(University of Florida)
27/08/2015, 09:00
To reach high frequencies while maintaining a good B^2V, the axion detector will require either a complex multi-cell structure or the operation of a number of cavities together. In order to employ a number of cavities that are power-combined in phase, the cavity resonant frequencies will need to be identical. This talk outlines a technique developed by Pound to lock a klystron to a resonator...
27/08/2015, 09:30
An overview of the R&D on increasing the quality factor of cavities using active feedback will be given.
Samantha Lewis
(University of California - Berkeley)
27/08/2015, 10:20
This talk will be a basic overview of Photonic Band Gap cavity design.
Dr
Dmitry Shchegolkov
(Los Alamos National Laboratory)
27/08/2015, 10:50
We report the results of recent design and testing of several 2.1 GHz superconducting radio-frequency (SRF) photonic band gap (PBG) resonators. PBG cells have great potential for outcoupling long-range wakefields in SRF accelerator structures without affecting the fundamental accelerating mode. Here we describe the results of our efforts to fabricate 2.1 GHz PBG cells with round and elliptical...
27/08/2015, 11:20
This talk will present an overview of the bead-pull technique that is being used to characterize cavities for ADMX and ADMX-HF.
27/08/2015, 11:50
Here we will discuss some of the work that has been done on mode-locked cavities at U. of Florida
Prof.
Konrad Lehnert
(JILA, University of Colorado)
27/08/2015, 13:10
The search rate of cryogenic axion cavity search will soon be limited by fundamental quantum fluctuations of the microwave field. In this talk, I will describe how this noise can partially be overcome using quantum squeezing of the microwave field. In contrast to what is often thought to be the case, I will show that it is in principle possible to measure both quadratures of the axion induced...
ling zhong
(Walther Meissner Institute)
27/08/2015, 13:50
Propagating quantum microwave signals are promising building blocks for quantum communication and quantum computation. In particular, such itinerant quantum microwaves can be generated by Josephson parametric amplifiers (JPAs) in the form of squeezed states. At the same time, JPAs are widely used as low noise amplifiers for the detection of microwave signals on the single photon level. In this...
Dr
Andrew Sonnenschein
(Fermilab)
27/08/2015, 14:40
Since dielectric materials inserted into a resonator cavity cause a permittivity- There are a number of dielectric materials which might be suitable for this application, but none have been sufficiently well studied in low-temperature, high magnetic field environments. The key issue is whether the necessary level of tunability can be achieved without prohibitively large energy dissipation. We...
Dr
Gianpaolo Carosi
(Lawrence Livermore National Laboratory)
27/08/2015, 15:10
He we will present an overview of R&D efforts to employ electronic tuning and coupling of microwave cavities.
Mr
Ian Stern
(University of Florida)
27/08/2015, 15:30
The axion is now by far the most promising candidate for the constitution of cold dark matter and this has generated a proliferation of searches around the world. While almost all CDM axion experiments use the Sikivie haloscope method, it is clear that to reach cosmological sensitivities at higher masses, new RF techniques that go beyond the current microwave cavity designs must be advanced....
Dr
Emilio Nanni
(SLAC National Accelerator Laboratory)
27/08/2015, 16:30
We present ongoing research and development in advanced microwave and millimeter-wave cavity design and fabrication at SLAC National Accelerator Laboratory. This research is primarily focused on improving the performance of accelerating structures with optimized cavity design for reducing breakdowns and increasing Q-factor, distributed coupling and improved fabrication with micro-machining and...
Dr
Berkowitz Evan
(LLNL)
27/08/2015, 17:00
Here we describe recent work to place a lower bound on the axion mass from lattice QCD calculations.
Dr
Gianpaolo Carosi
(Lawrence Livermore National Laboratory)
27/08/2015, 17:20
End of the workshop discussion.