First Experiments at the Yale Ka-band Test Facility* M.A. LaPointe, 1 Y. Jiang, 1 S.V. Shchelkunov, 1 V.P. Yakovlev, 2,3 S.Yu. Kazakov, 2,4 J.L. Hirshfield,

First Experiments at the Yale Ka-band Test Facility*

M.A. LaPointe,1 Y. Jiang,1 S.V. Shchelkunov,1 V.P. Yakovlev,2,3

S.Yu. Kazakov,2,4 J.L. Hirshfield,1,2 A.L. Vikharev,2,5 A.A. Vikharev,2,5

O.A. Ivanov,2,5 A. Gorbachev,2,5 M. Lobaev2,5

1Yale University, New Haven CT, 2Omega-P, Inc., New Haven CT3FNAL, Batavia IL, 4KEK, Tsukuba, Japan, 5IAP, Nizny Novgorod, Russia

*Sponsored by US Department of Energy, Office of High Energy Physics

Advanced Accelerator Concepts WorkshopSanta Cruz, CA 27July - 2 August 2008ÎUniversity Omega-P, Inc.

Outline• Status of Facility• Initial Experiments

* Quasi Optical Active Pulse Compressor* RF Breakdown Cavity for material and alloy

testing

• Waiting Experiments* Pulsed Heating Cavity* Diamond Breakdown Cavity

• Planned Experiments* Hidden Sector Physics* ?


Status of Facility


The Yale Ka-band Test Facility began operation as a user facility 1 Sep, 2007.

Initial tests of a Quasi-optical pulse compressor and a cavity for breakdown studies have begun.

Status of Facility


During initial experiments no resonance was observed in 34 GHz QO pulse compressor. An unanticipated mode was discovered which operated at 31.9 GHz. Mode is dependent on the circuit outside of output cavity. Magnicon parameters were found which do not excite this mode. Interferometer system was set up to monitor the magnicon frequency

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31.895 GHz

34.285 GHz

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Magnicon output

34.296 GHz

31.890 GHz

Status of Facility


A Cryomech helium reliquefier has been ordered and is due to arrive early August. The unit will provide 6 l/day of LHe recycling which is about the loss rate while operating the SC magnet. Any net loss can be made up by gaseous helium which then is liquefied. This will allow the facility to run year round without having to partially shut down due to helium costs.

Initial Experiments: Quasi Optical Active Pulse Compressor

A.L. Vikharev, A.A. Vikharev, O.A. Ivanov, A. Gorbachev, M. Lobaev


•After attempts at passive compression with both copper and active gratings were unsuccessful it was discovered that the magnicon was operating in an unanticipated (parametric?) mode at 31.9 GHz.

•An initial operating regime was found for the magnicon which gave the proper third harmonic output at 34.3 GHz, albeit at low power (~250 kW/arm).

Initial Experiments: Quasi Optical Active Pulse Compressor


• After magnicon operation was in proper mode, the resonance in the QO active pulse compressor was seen.

• The next set of experiments which will include the use of the active grating is scheduled for October

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RF Breakdown Cavity


This device to measure surface breakdown on specially prepared pins is currently installed.

The device consists of a TM030 cavity with two axial pin protrusions.

The pins are to be made from various metals and alloys to test their relative breakdown properties.

The electric field is designed to be maximum on the surface of the protrusions.

Initial breakdown (conditioning?) events were observed with ~200 kW of incident power corresponding to ~ 20 MV/m electric fields.

RF Breakdown Cavity


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S11 at Room Temperature (dB)S11 at Warm Temperature (dB)

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The cavity is tuned by either adjusting the pin spacing in the cavity or the temperature of the cavity.

Efforts are made to make the pins symmetric in the cavity.

After adjusting the pins to be symmetric, the temperature of the cavity is adjusted to retune the resonance as indicated in the graph.

Pulsed Heating Cavity


•The TE011 test cavity schematic layout and the RF magnetic field pattern are shown in the figure below. •The protrusion peak magnetic field intensity is 3x larger than the next highest field point.•The geometry, including input coupler, is axisymmetric to minimize surface electric fields.

Diamond Breakdown CavityS.Yu. Kazakov. V.P. Yakovlev, A.L. Vikharev, et al


• Diamond test cavity (H02 mode) is built and in house awaiting installation.• Cavity is designed to test surface and volume breakdown limits for CVD diamond.• Tests will include hydrogenated and de-hydrogenated diamond samples• First tests scheduled for Oct/Nov ‘08

Hidden Sector PhysicsO.K. Baker, P.L. Slocum, Yale University


•An experiment is being designed to look for hidden sector photons (HSPs), a gauge boson interacting with matter via gravity like interactions.

•The masses of these HSPs are expected in the sub-eV range (30 GHz ~ 100eV).

•The experiment consists of two high Q cavities in up to a 7 Tesla magnetic field.

•The expected photon yield is given by the estimate

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212 QQBQQPP beamLNB

Further Collaborations Welcomed


There have been a few additional inquiries into using the Yale Ka-band Test Facility

Your Experiment Here

Documents

First Experiments at the Yale Ka-band Test Facility* M.A. LaPointe, 1 Y. Jiang, 1 S.V. Shchelkunov, 1 V.P. Yakovlev, 2,3 S.Yu. Kazakov, 2,4 J.L. Hirshfield,