The Extreme Axion Experiment (X3)

S. Al Kenany, University of California, Berkeley
Kyoto University, Division of Physics and Astronomy, July 26, 2016

Outline(Very) brief basics on the axion
The microwave cavity search for axionic dark matter
How to improve its mass reach, speed and sensitivity
What next?

The Axion

••
•
•
•
•

Strong CP (charge parity) problem – standard model predicts:
significant amount of CP violation in strong interactions(compared to experiment)
neutron dipole moment nine orders of magnitude larger thanthe current experimental limitPeccei and Quinn proposed the axion as a solution to thisstrong• CP problem

Axion basics (arm-chair science – what you learn for free)Light cousin of #0: J#= 0–ga"" (GeV–1)

10–8

10–10

"aHorizontal BranchStar limit

10–12$a > 1

Sn1987a

10–14

Total density ! (mass)–7/6

Axion
models

10–16
10–6

10–4

ma (eV)

Couplings ! Axion mass

10–2

100

Good news – Parameter space is bounded
Bad news – All couplings are extraordinarily weak

Axion production quenches
neutrino pulse from SN1987aif mass too big (~ meV )Ordinary stellar burning rulesout axions if coupling too big

Why is this hard? Why not just look for an unidentified radio line at which E" = ma / 2 ?

(from anybody’s halo, including our own)"a"

The difficulty is that the spontaneous decay lifetime ~ 1060 sec for ma ~ µeVThe)Primakoff)Effect

MagnetB&""%

a'Classical$EM$field

theSea$of$virtual$photons

Primakoff$EffectThe)microwave)cavity)axion search)– Your)car)radio)on)steroids

Axion conversion power and signal detection – details

Linear amplifiers are subject to the Standard Quantum LimitMicrostrip SQUID.amplifiers(John&Clarke,&UCB&Physics)

But.ideally.amplifiers.can.be.
quieter.still.&.beat.the.SQL

ADMX is the world’s quietest spectral receiver

Dicke Radiometer equation:s Ps=n kTnt

Systematics>limited.for.signals.of.10>26 W...– 10>3 of.DFSZ.axion power.
Last.signal.received.from.Pioneer.10.(6.billion.miles.away).~.10>21 W..

What.does.the.data.look.like,.and.candidates?

Signal)maximizes)in)the)wings,)and)furthermore)is)episodic)) → Radio)peakDistributed)over)many)subspectra)(good),)but)didn’t)repeat)))→ Statistical)peak)Limits)on)the)axion after)twenty)years

HEMT<2004

SQUID
2007-09

Team ADMX-HF – Extreme Axion Experiment (X3)
Yale University (experiment site)
Steve Lamoreaux, Ling Zhong, Ben Brubaker, Sid Cahn, Kelly Backes

UC Berkeley
Karl van Bibber, Saad Al Kenany, Maria Simanovskaia, Samantha Lewis,
Jaben Root, Nicholas Rapidis,

CU Boulder/JILA
Konrad W. Lehnert, Daniel Palken, William F. Kindel, Maxime Malnou

Lawrence Livermore National Lab
Gianpaolo Carosi, Tim Shokair

X3 Rationale and Goals
Both Innovation Test-bench and Data Pathfinder
Identify and resolve challenges for 5–25 GHz (20–100 µeV)
Develop new cavity and amplifier technologies, validate in ops!
$ρ22a
PSIG = η gaγγ # & B QC V Cnml
" ma %PSIG
SNR =kBTSYStΔν aOur original “Technical Design Report”

And that’s about how it looks now …

Microwave Cavity
Cu body with off-axis tuning rod
Tunable over 3.6 – 5.8 GHz
QC ~ 20,000
Stepping motors and Kevlar lines used for motion

Josephson Parametric Amplifiers• Josephson Parametric Amplifiercomposed of SQUIDs• Tunable from 4.4-6.5 GHz with
20 dB of gain
Persistent coils forfield cancellation

JPAs require a magnetic
Field-free environmentEfficacy of the magnetic shielding system for the JPAs

Integration of the Experiment at Yale (I)Josephson Parametric Amplifier

3He/4He Dilution

Refrigerator

Microwave Cavity (copper)

9.4 Tesla, 10 Liter Magnet

Integration (II) and Infrastructure Details
Superconducting magnet––––Made by Cryomagnetics, Inc.
Maximum field of 9.4 T
Large bore
Dry system

JPAlocation

ThermalshieldDilution refrigerator– 25 mK base temperature– Experiment operates at 100 mK tostabilize the JPA– Thermal shield contains gantry, JPA,and cavity

Cavitylocation

Data analysis– Two analysis sites: Yale and Berkeley

Magnet“It takes a licking, andkeeps on ticking!”
John Cameron Swazey,
Timex commercials,
1950’s & 60’sSnowstorm knocked out Yale’s central power station

Experienced amagnet quench
in early March
Surprisingly
little damage
Repairs complete,experiment back inoperation mid-MayProject timeline & first data run

First run in f ~ 6 GHz range (Jan – July 2016)
TSYS ~ 1100 mK ( ~ 3.5 TSQL ; “hot rod” problem )Reach ga"" ~ 2.5 KSVZ, ~ 2 KSVZ with new thermal link
The first data run should conclude by the end of July

Preliminary Data

Data quality appears very good
Synthetic axion
signals injectedCandidates
for rescan

SNR increasing with coaddition of subspectra

The near-term program
Higher frequency run with “hotrod” mitigation (early fall 2016)
Swap in Blue Fors fridge
Deploy, run squeezed-vacuum
state receiver (early 2017)
Will take significant rework of exp’t
To reduce TSYS < TSQL
To our knowledge, only LIGO/GEO
have employed squeezed-states inan actual operating experiment

Microwave cavity enhancements(mid-2017)

The Scourge of Mode Crossings25.0

ωb/c(a)10.0
5.0

Photonic
Band Gap
Resonators

0.0(Samantha Lewis)

20.0(b)TM band

15.0

gaps

ωb/c

15.0
10.0(c)TE band

5.0
0.0
0.0

E (V/m mag. in dB)

gaps

0.1

0.2

0.3

a/b1200.4(d)

80
400-40
4.0

4.2

4.4

4.6

4.8

5.0

Frequency (GHz)5.2

5.4

5.6

0.5

Open structure
designed to trap
TM modes, butallow TE modes
to radiate away
Cleanses thespectrum of theforest of modecrossings, andthus dramaticallyaccelerates thescan rate of theexperiment

Thin-film Type-II superconducting cavities to improve Q(Maria Simanovskaia)

Thin NbTiN films have been successfully madeNb0.30Ti0.67O0.03 : 280 nm%##$6)787.-9:)$0!2$

%#3&$

%#34$

%#35$

!"#$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$%&"'$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$'#$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$()*+),-./,)$012$

We are also pursuing Dielectric Bragg Resonators to improve Q

Excluded.gA"" vs..mA with.all.experimental.&.observational.constraints

ALPS IIIAXO

Excluded.gA"" vs..mA with.all.experimental.&.observational.constraints

ALPS IIIAXOAxion from)Hell
CASPEr ,&LC

ORPHEUS,&ARIADNE

And if the axion be found?

And should the axion possess very narrow fine-structure, it would
constitute a “movie” of the formation of our Milky Way galaxy.

Modulation of one infall line(Movie)

Vector DM Flow is uniquely determined

Annual Modulation: Earth’s orbit around Sun(Movie)

Daily Modulation: Earth’s spin on its axis
(Movie)Additional Slides

Josephson Parametric
Amplifiers (JPA)
Konrad Lehnert, JILA/CU•

Natural for higherfrequencies• Broadly & easilytunable• Operates at the SQLor below (squeezing)• ADMX-HF initially
utilize an existing andproven system design– 4-8 GHz– Quantum-limited T

Thin-film Type-II superconductors appear promising

10 nm Nb0.5Ti0.5N is perfectSupports B|| up to 10 Tesla

Q of the TM010 mode for a conventional Cu cavity:RL

Q =L!R
1 + L/R.R!

The concept of a hybrid superconducting cavity:
RThin-film superconducting barrel

Copper end-caps

L

Q =L!R
1 + L/R.R!

This term goes away for asuperconducting barrel

Qhybrid = (1 + L/R) . Qcu
For typical ADMX cavity, L/R = 5, enhancement factor = 6