Any Light Particle Search II (ALPS II)

detectors
and for
DAQ
Searching
Axion-like Particles with Optical Cavities
Aaron
Spector
Klaus
ZenkerInternational workshop on Axion
physics and dark matter cosmology

Osaka 02,
University,
February2015 Japan
December 20-21, 2017

Klaus Zenker

TES detectors and DAQ

1

Overview‣ Three questions:• How can optical cavities help us search for Axion-like particles?

• What challenges exist when using optical cavities?

• Where do we currently stand in addressing these challenges?

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 2__Axions
and Axion-like-particles
On Axion• The strong CP problem : why the dimensionless‣ Solution
to theθ strong
CP problemsmall.
parameter
is so unnaturally• Spontaneous U(1) symmetry breaking at a specific• Axion cancels terms that break CP symmetry in QCD Lagrangianenergy scale fa (Peccei & Quinn 1977) to solve CPviolation → existence of Axion (?).
• Coupling with photon:‣ Coupling between Axions and photons‣ Axion would explain various astrophysical phenomena• Stellar cooling excesses• TeV transparency‣ Axion-like particles
Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 3__

Experimental Axion Searches ❖ Haloscope: resonance cavi

• Under the preconverted into
enhanced.

‣ Haloscopes: ADMX
• Axions in DM halo
• Microwave cavities with B-fields• Haloscope shrange from 10‣ Helioscopes: CAST, IAXO
• Axions generated by the sun• Light tight X-ray telescopes in B-fields‣ Light-shining-through-a-wall (LSW): ALPS I, ALPS II• Creating Axion-like-particles in lab with lasers and B-fields
ADMX Experiment
Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 4__

LSW Experimental Concept‣ Axion-like-particles generated by high power laser source in B-field• Propagates though region of strong B-field toward wall

‣ Axions-like-particles reconverted to photons behind wall
• Region of strong B-field behind the wall
• Light tight enclosure prevents light from entering regeneration area
• Regenerated photons measured with a single photon detector

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 5__

ALPS II Concept

Women = time ⇥ $‣ Production cavity increases✓ circulating◆ 1 ✓ power before wall

1
Dn 8
1
Increases
the flux of axion-like-particles through the wall• S(g↵ ) /
B·Lt
De · P C · RC · Pi

‣ Regeneration cavity resonantly enhances probability of a ➜ Ɣ◆18

1 2 component
Plaserof the Axion-liketheelectromagnetic• Amplifies
N ! ! =⌘ PC RC(g↵ BL)4 ⌧ field
16
E‣ Number of regenerated photons:
FRC 1
NS = ⌘ NPC(g↵ BL)4⇡ 16
2

Production Cavity (PC)Regeneration Cavity (RC)S = A sin (!t + )
⇠
⇠
A
A
⇠
⇠+ )
⇠
I = A sin (!t + ) · sin (!t) = cos( )cos(2!t⇠⇠2
2 ⇠ Detector
Wall⇠⇠
Magnet StringAA⇠⇠
Q = A sin (!t + ) · cos (!t) = sin( ) + ⇠sin(2!t⇠⇠ + )
Laser

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 6__

y stating that women are the product of time and money.
ALPS II Design Parameters

Women
= ⇥$
‣ Magnets: 5.3 T superconducting
HERA dipoles, 10 per cavity

roduce• theaxiom
thatfield
timeequalsmoney.
468 Tmmagnetic
lengthper cavity‣ Production cavity: 100 m, 30 W input laser, 5000 power build up

Women = time ⇥ $• 150 kW circulating power in the PC‣ Regeneration cavity: 100m,✓ 120,000◆ 1 ✓ finesse

1
Dn 8
1
state
of
the
art
of
mirrorsfor~100m
cavities•S Current(g↵ ) /
B·Lt
De · P C · RC · Pi

1 sensitive
Plaserfactor ~3000 more
than
ALPSI
‣ ALPSIIN
2
= ⌘
(g

◆1
8

4
BL)
⌧
↵

! !
PC RC
16
E
• Factor of 14 from the RC, 21 from BL, 3.5 from PC power

FRC 1
NS = ⌘ NPC(g↵ BL)4⇡ 16
2

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 7__

ALPS II Sensitivity

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 8__

ALPS II Sensitivity

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 9__Experimental Challenges‣ Regeneration cavity introduces several challenges• Dual resonance• PC circulating field must be resonant with RC• Light Tightness• Can’t use IR light to maintain length stability• Spatial overlap• PC and RC spatial Eigenmodes must overlap
Production Cavity (PC)Regeneration Cavity (RC)

Laser

Detector
Magnet String

Wall

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 10__

ALPSIIa Pathfinder Experiment‣ Test optical systems for ALPSIIc‣ 10m collinear cavities, no magnets‣ Sensitive to Hidden Photons‣ Full optics demonstration summer 2018

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 11__

Cavity Status for ALPSIIa‣ Production Cavity:• 35 W input power, power build factor of 4000 (low power operation)• PDH frequency stabilization, auto-alignment• 50 kW stable high power operation (requirement: 150 kW)‣ Regeneration Cavity• Measured finesse of 93,000 (requirement: 120,000)• Implemented length control system

Characterization of optical systems for the
ALPS II experimentet] 18 Oct 2017Vol. 24, No. 25 | 12 Dec 2016 | OPTICS EXPRESS 29237

A ARON D. S PECTOR , 1,* J AN H. P ÕLD , 2 R OBIN B ÄHRE , 3,4 A XEL
L INDNER , 2 AND B ENNO W ILLKE 3,4

1 Institut für Experimentalphysik, Universität Hamburg, Luruper Chaussee 149, D-22761 Hamburg,

Demonstration of the length stability
requirements for ALPS II with a highfinesse 10 m cavity
Jan H. Põld,1,* and Aaron D. Spector1
1

Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, D-22607 Hamburg, Germany*
jan.pold@desy.de

Germany
2 Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, D-22607 Hamburg, Germany
Light-shining-through-a-wall experiments represent a new experimental approach to
3 Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Callinstraße 38 D-30167
search for undiscovered elementary particles not accessible with accelerator based
Aaron
Spector|International
Workshopon“AxionPhysicsandDark
Matter
Cosmology”| Osaka, Japan | December 20-21, 2017 | Page 12__experiments. The next generation of these experiments, such as ALPS II, require
Hannover, Germany
4 Institute for Gravitational Physics of the Leibniz Universität Hannover, Callinstraße 38, D-30167
high finesse, long baseline optical cavities with fast length control. In this paper

Dual Resonance Concept‣ PC resonance condition maintained with PDH frequency control loop

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 13__

Dual Resonance Concept‣ PC resonance condition maintained with PDH frequency control loop
‣ RC length must be resonant with PC circulating field• RC RMS frequency noise must be < 10% RC IR line-width• RC RMS length noise must be < 0.5 pm (ALPS IIc)

‣ Light tightness: Frequency double 1064 nm to 532 nm (green)• RC must be stabilized to < 1/10,000 of a line-width for 532 nm

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 14__

Dual Resonance Concept‣ PC resonance condition maintained with PDH frequency control loop
‣ RC length must be resonant with PC circulating field• RC RMS frequency noise must be < 10% RC IR line-width• RC RMS length noise must be < 0.5 pm (ALPS IIc)

‣ Light tightness: Frequency double 1064 nm to 532 nm (green)• RC must be stabilized to < 1/10,000 of a line-width for 532 nm‣ Check by opening shutter

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 15__

Dual Resonance Status‣ Length actuator developed• Custom mount with Piezo• Suppressed in-loop length noise to < 0.3 pm• Next step: out-of-loop measurements‣ Effective point of reflection changes• Must be suppressed < 0.5 pm

12• Measured 0.4 nm changes in 1 hour

10Change in EPR over 1 hour measurement
0.4
0.35

"f (kHz)

0.25
6

0.2
0.15

4

0.1
2
0.05
0
0

10

20

30

40

50

60

Time (minutes)
Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 16__070

"EPR (nm)0.38Spatial Overlap‣ RC must maintain 95% spatial overlap with the PC• Cavity mirror alignment requirement: 5 µrad (ALPS IIc)
• Central breadboard used to maintain alignment• Measured < 1 µrad drift in 1 week
• Active alignment of end mirrors

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 17__

Optics Status Summary

Requirement

StatusPC circulating power

150 kW

50 kW

RC finesse

120,000

93,800Spatial overlap> 95%• Breadboard mirror alignment
meets requirements

RC length stabilization< 0.5 pm

< 0.3 pm

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 18__

ALPSII Detection Schemes‣ Two independent detection schemes• Transition Edge Sensor (TES)• Microcalorimeter measures temperature change induced byphoton on absorber• Dilution refrigerator purchased from BlueFors (April delivery)• Heterodyne detection scheme• Regenerated photons coherent with PC circulating field• Coherent summation of measurement signal over time
• Incoherent summation of noise

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 19__

Future Challenges and Timeline‣ Demonstration of dual resonance• Operate both cavities simultaneously, mitigate EPR changes‣ Demonstration of spatial overlap‣ Light tightness‣ Detector development‣ Timeline• ALPS IIa full optics concept demonstration summer 2018
• ALPS IIc optics commissioning beginning fall 2018
• ALPS IIc data runs in 2020

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 20__

Thanks for listening!
> Any questions

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 21__

Production Cavity Status‣ Requirements: 150 kW of circulating power• 30 W input power• Design power build 5000
• Automatic alignment system‣ Measured power build up 4000 at 0.5 W• Losses of 115+-35 ppm (power build up factor without losses 4500)‣ High Power operation with 30 W input power• Thermal effects ➜ reduced circulating power• 50 kW stable operation
Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 22__

Regeneration Cavity Status‣ Measured finesse of 93,000 (design for 120,000)• 39 ppm losses (23 ppm design)
10 1

Transmitted Power [a.u.]

Measurment
Exponential Fit

10

10

0

-1

10 -2
-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

Time [ms]Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 23__

RC Length Stabilization results
10 -8

10

Error Signal NoiseControl Signal Noise
Filtered Error Signal Noise
Projected ALPSIIc Requirements-9Length Noise (m/rtHz)

10 -10

10-11

10 -12
10 -1310-14

10 -1510-16

10 -17
0
10

10

1

10

2

10

3

10

4

Fourier Frequency + (Hz)Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 24__Effective Point of Reflection Measurement‣ Measured EPR changes• Simultaneously locked 532 nm and 1064 nm to RC• Measured relative drift of resonant frequencies• 11 kHz RMS over ~1 hour (0.4nm)
Change in EPR over 1 hour measurement

12

0.4
10

0.35

"f (kHz)

0.25
6

0.2
0.15

4

"EPR (nm)

0.3

8

0.1
2
0.05
0
0

10

20

30

40

50

60

0
70

Time (minutes)
Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 25__

Heterodyne Detection‣ Interference beat note between measurement signal and local oscillator• Phase relation between measurement signal and LO fixed• Coherently sum by demodulating at signal frequency‣ Demonstrated 2 week data run with no spurious signals from ADC‣34), shown as the dashed green line. Since the expectation value of our data lies on top of the shot noise limit
after 2nd demodulation, shot noise is in fact the dominantPC-RC
distance
fixed
by threshold
ULE platenoise
source inour setup. The
5-sigma(purple)and the expected value for noise are based on the amplitude spectral density of the raw data out of the FPGA atin phase lock loop
• Lasersa Fourierfrequency of 2.5 Hz (see Equation 15).
This measurement not only verifies that our system isshot noise limited and behaves as expected but also showsthat no spurious signals are picked up over the entire 19
day integration time when Laser 2 was turned o↵.

8

Signal present at 2.4 Hz

5s
igm

ad

ete
ctio

n li

mit

3.33 x 10-2 photons
per second

Demodulation at exactly 2.4 Hz
Demodulation at 2.4003 Hz
Demodulation 2.5 Hz
Expected value (no signal)

4.2.

Weak Signal Generation and Detection

Integration time τIn order to demonstrate that a signal is observable using
heterodyne detection, we generate a beat note between the
LO and an ultra-weak sideband of a second laser. Current
FIG. 7: Shot noise limited signal measurement scaled to photons
Aaron
Spector | powers
International“Axionand Dark
Matter Cosmology”| Osaka,| December 20-21,
2017__
per second.
TwoJapandemodulation
stagesare| Pageused26witha signale↵ectivesideband
areWorkshop
limitedonto
10 Physics
5 photons
perpresent at 2.4 Hz. The result when second demodulating is atsecond and above. This is due to a spurious phase coherent

S

S

"This
onant photon regeneration requires
I noisefield,
mode
matched "toQthe photon-regenerat
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Detectionof thiscavity must be
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ity, will propagate towards the photodetector whic
esonance of the axion generation
ﬃ phasepﬃﬃﬃﬃﬃﬃﬃﬃ
If we could
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SQ
SI adjustused
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Interference beat note between
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local
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ﬃIQof laser 2 of frequency !2 that is
as thephaselocal oscillator
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fortheexample
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Light relationfrom laser
2 will measurement
Phase
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• 1.
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ted signal will then be amplified
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whe
Sweek
¼
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#S
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(29)
data
run
with
no
spurioussignals
ADC• Demonstrated
withLOthe otherpaths.
Therefore,
itis.meascurre
I cos!tQ
rence frequency is then identicaltonoisein the detection process will bethe
shoamplitude
intosourcethesignal:pﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
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clear
how
adjustthisphase.
Instead,itislikely
"
!
,
which
will
be
set
to
equal
a
Therefore,
itisconvenienttoexpressthesignalin12
where
SQis¼arbit
NLO
NﬃS cos!process
2 N
Sduring
Dur
I ¼q2ﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
starting
phase
thedetectionp
ﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
the number of photons
in2 both fields:
spectral range of the photon2

qﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
p
ﬃﬃﬃﬃﬃﬃﬃﬃﬃ
2
2¼ "I þ "Q ¼ 2 NLO ;(3

hot noise isthe
2 NLO NS : to mea
SpI ﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
þ both
SQ ¼quadratures
pﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
that we haveSto
combine# ¼
arethequadraturecomponents
of
Sthe
(30)
NS cos! in¼two
2 N
SI ¼ 2 NLOamplitudeCon
Q signal:
LO NS sin!
#
Thenoiseshot innoiseorquadratures
variance inadds
each
Similarly,
the
shot
both
qu
q
ﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
ﬃ
072004-7
p
ﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
S calculated
the number of photons
are the two quadrature
offromthe signal.
cally, components
S# ¼ S2I þ S2Q ¼ 2 NLO NS :quadraturecanbeﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ#The shot noise or variance in eachp
ﬃﬃﬃﬃﬃﬃ
ﬃ
pSqﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
p
ﬃﬃﬃﬃﬃﬃﬃﬃﬃ"
calculated from the number of photons
detected:
22N ¼
2N
¼
2 "I ¼
2
LOCha
;
¼
N
¼
"
þ
"
Similarly, the "
shot
noise
in
both
quadratures
adds
q
#
LO
I
Q
mo
cally,pﬃﬃﬃﬃﬃﬃ"ﬃ pﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ pﬃﬃﬃ
"I ¼ 2N ¼(31) conseq"Qis: a fundamental
The2N
factorLO ¼ 2and the signal to shot noise isS"

pﬃﬃﬃﬃﬃﬃ¼ N ;(3

number of regenerated photons in t
Aaron Spector | PRC Open Session | March 21-22, 2017 | Page 27__

Effective Point of Reflection Changes‣ RC mirrors will have different EPR for 532 nm and 1064 nm• EPR changes also subject to < 0.5 pm requirements• Layer thickness of coating stacks: CTE• Index of refraction of layers: dn/dT• Measured drift of resonant frequencies

Change in EPR over 1 hour measurement

12

0.4
10

0.35
0.3

"f (kHz)

8

0.25
6

0.2
0.15

4

0.1
2
0.05
0
0

10

20

30

40

50

60

Time (minutes)

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 28__070"EPR (nm)• 0.4nm RMS over ~1 hourSpatial Overlap‣ RC must maintain 95% spatial overlap with the PC• Cavity mirror alignment requirement: 5 urad (ALPS IIc)
• Monolithic aluminum breadboard used to maintain alignment‣ Measured alignment drift of PC RC mirrors on aluminum breadboard• RMS < 1 urad

0.6

‣ Aligned RC with PC transmitted• Frequency stabilized PC• Observed flashes offundamental mode intransmission of the RC

0.4
0.2

angle [urad]beam as alignment referencedelta xdelta y

0.8

0
-0.2
-0.4
-0.6
-0.8
-1
-1.2
0

20

40

60

80

100

120

140

160

180

time [h]Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 29__

Optical Layout Table 1

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 30__

Magnets‣ Using HERA dipole magnets• 5.3 T superconducting magnets• 600 m radius of curvature• Unbend cold mass
• 4 have been unbent

Beam Axis (mm)

20
15
10
5
0

• Successfully operated• 48 mm free aperture (need 40 mm)

0

2

4
6
8
Horizontal Position (m)pressure screw

cold
mass
cold

pressure props

Page 31

Aaron Spector | 12th PATRAS Workshop, Korea | June 23, 201610

ALPS II Sensitivity to Hidden Sector Photons

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 32__

Long baseline optical resonators

ALPS IIa RC design sensitivity

squeezed light/ vacuum
magnetic birefringenceexperiments
ALPS IIc RC design sensitivity

LIGO

plot from LIGO T-1400226-v6
Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 33__

Long baseline optical resonators

20m Cavity (September 2015)
20m Cavity (February 2015)

ALPS IIa PC (September 2016)
ALPS IIa RC (February 2017)
ALPS IIa RC (September 2017)
ALPS IIa design sensitivity

squeezed light/ vacuum
magnetic birefringenceexperiments
ALPS IIc design sensitivity

LIGO

plot from LIGO T-1400226-v6
Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 34__

ALPS II Design Parameters and Sensitivity Gains

Parameter

Scaling

ALPS-I

ALPS-IIc

Sens. gain

Effective laser power Plaser

gag µ Plaser

1/4

1 kW

150 kW

3.5

Rel. photon number flux ng

gag µ ng

1/4

1 (532 nm)

2 (1064 nm)

1.2Power built up in RC PRC
BL (before& after the wall)
Detector efficiency QE
Detector noise DC
Combined improvements

gag µ Preg
gag µ (BL) 1
gag µ QE 1/4
gag µ DC1/8

1/4

1
22 Tm
0.9
0.0018 s 1

40,000468 Tm0.75
0.000001 s 1

14
21
0.96
2.6
3082

Table 1. Parameters of the ALPS-I experiment in comparison to the ALPS-II proposal. The second columshows the dependence of the reachable ALP-photon coupling on the experimental parameters. The lacolumn lists the approximate sensitivity gain for axion-like particle searches compared to ALPS-I. The masensitivity gain is due to the enhanced magnetic length arising from the 2⇥10 HERA-dipole magnet strin
cf. Tab. 3 for details. A sizable additional gain arises from the installation of a regeneration cavity (RCcf. Sect. 3.2 for details. A further upgrade comes also from the detection side. The numbers given in thtable Aaron
are fora transition
sensoras thisthe detector
is expected
to |beused
35__ in the fin
Spector| Internationaledge
Workshopon “Axiondetector,
Physics and Dark
Matteris
Cosmology”| Osaka, which
Japan | December
20-21, 2017
Page
version of all three stages of ALPS-II, see Sect. 3.4 and Tab. 2 For hidden photons, there is no gain from thALPS II Optical Layout

Figure 12. Layout of the ALPS-IIb and ALPS-IIc optical tables.
Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 36__

Detection Schemes

RL

T
ΔT

‣ Transition Edge Sensor (TES) t

Vout

τeff

ΔT ~ 100
300 μKτeff ~ 1.5 μs
t

Vbias

R

set pointLnormalδR ~ 1 Ωsuperconductive

Ro(T,I ) C

t
T

TC
I

chip
,

Tbath< TC

Tbath = 80 mK
TC = 140 mK

ΔI ~ 70 nAt

Based on sketch from [de Korte
et al. (2003), Proc. SPIE 4851]

R

V

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka,LJapan | December 20-21,
out 2017 | Page 37__

pticalpaths.
Therefore,
it is currently not
onant photon
regeneration
requires'!rms ¼
This field, mode matched to the photon-regenerat
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of
the
photonqﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
pﬃﬃﬃﬃﬃﬃﬃﬃﬃ
signal. A satisfactory s
22(34)# ¼ "I þ "Q ¼ 2 NLO ;components on a breadvery low coefficient
072004-7
shot noise is
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1

2

9

10-2

10-3

10-4

10-5

10-1

100

101

103

104

105

Results
Mainz
Meeting
7 March2017
38__
Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | Preliminary
December
20-21,
2017| PageStellar energy loss excess‣ WDs, RGs, and HB systematically cool more efficiently than expected• Axion or ALP coupling to photons and electrons best explains excesses

best fit:g ae = 1.5 × 10−13
g aγ = 0.14 × 10−10 GeV -1

χ2min/d.o.f. = 1.14

Aaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 39__

TeV Transparency‣ Energetic photons undergo pair production• Expected to attenuate
high energy photons
from extra-galactic
sources• Intergalactic space
appears transparent forthese photons• Coupling to axions of
ALPs could explain thisAaron Spector | International Workshop on “Axion Physics and Dark Matter Cosmology” | Osaka, Japan | December 20-21, 2017 | Page 40__