cold dark matter axion search with a dipole magnet · oct cern spsc committee review and approval...

Cold Dark Matter Axion Searchwith a Dipole Magnet

Lino Miceli

IBS Center for Axion and Precision Physics Research (CAPP/IBS)

At the Korea Advanced Institute of Science and Technology (KAIST)

Daejeon, Republic of Korea

Identification of Dark Matter 2016Sheffield 18-22 July 2016

Outline

2Lino Miceli – IDM 2016 – Sheffield, 18-22 July 2016

• Introduction

• RF rectangular cavities dipole magnets

• The CAST-CAPP/IBS Project CAST = Cern Axion Solar Telescope

CAPP = Center for Axion and Precision Physics Research in KAIST (South Korea)

IBS = Institute for Basic Science (CAPP funding agency)

The CAPP Program


Focuses on two key issues of contemporary physics:

• The nature of dark matter. Investigated through an extensive axion search program that constitutes the main CAPP thrust.

• [ The origin of the matter anti-matter asymmetry of our universe (R&D towards a proton EDM experiment) ]

CAPP main goals in axion search


• Establish state of the art axion dark matter experimental program at KAIST

• R&D program to improve on all experimentally accessible parameters in microwave searches

• Promote/contribute-to international collaborations• The object of this presentation is an example

CAPP is leading a new experimental effort (CAST-CAPP/IBS project) within the CAST program to search for cold dark matterwith rectangular cavities in the CAST dipole magnet

Axion Search Motivation


The axion arises as a consequence of the Peccei-Quinn solution to the strong CP problem (the measured upper limit of CP violation in strong interaction is ~10 orders of magnitude smaller than predictions)

The axion is a good cold dark matter candidate if its mass is in the range ~ (1 – 100) meV

CAPP Axion Search Main Method


Based on the axion coupling to two photons in the presence of a strong magnetic field

ℒ = 𝑔𝑎𝛾𝛾𝑎(𝑡)𝑬(𝒕) ∙ 𝑩

𝑔𝑎𝛾𝛾 coupling constant

𝑎(𝑡) axion field

B provides a virtual photon enhancing the conversion

probability

E(t) electric field associated with the outgoing photon

Detection Technique


Haloscope: the a xion-to-photon conversion probability is further enhanced if

the process occurs in a microwave cavity that resonates to the frequency of the axion mass (Sikivie). Tunable cavities

On-resonance axion conversion power in a microwave cavity

𝑃 ≈ 𝑔𝑎𝛾𝛾2 𝜌

𝑎

𝑚𝑎

𝑩𝟐 ∙ 𝑸 ∙ 𝑽 ∙ 𝑪

𝑄 = 2𝑓Stored Energy

Power LossQuality factor

𝐶 =1

𝐵02𝑉

𝑩∙𝑬𝑑3𝑥2

𝑬∙𝑬𝑑3𝑥Geometry factor


• Rectangular cavity resonant frequencies

𝑓𝑙𝑚𝑛~𝑙

𝑤

2+

𝑚

ℎ

2+

𝑛

𝐿

2

• Resonant E field aligned with the external B field: 𝑇𝐸𝑙0𝑛 modes

𝐸𝑦 ~ sin𝑙𝜋

ℎ𝑥 sin

𝑛𝜋

𝐿𝑧

𝐸𝑥 = 𝐸𝑧 = 0

CAST-CAPP/IBS search: rectangular geometryFirst experiment using rectangular cavities in a dipole magnet

CAST-CAPP/IBS Search: The CAST Dipole Magnet

9

LHC prototype

9 T operating field

1.8 K operating temperature

9.25 m magnetic length

43 mm twin bores

Cavity installed here

Magnet front end

Lino Miceli – IDM 2016 – Sheffield, 18-22 July 2016


2015, Jan Work begins; start looking for collaborators

Mar Presented proposal to CAST

June Proposal to CERN (within CAST)

July Project promoted by the CERN SPSC referee

Sep Responded to SPSC referee comments

Oct CERN SPSC committee review and approval

Nov Started cavity design

Dec First integration meeting

2016, Feb Vacuum vessel design

Mar Fabrication of all-copper cavities (not a good idea)

Apr Upgraded cavity design and material (Cu-plated stainless steel)

May OK to install received by CERN committee including magnet experts

June One small rectangular cavity installed in the CAST magnet

CAST-CAPP Project History

Cartoon of cavity inside the bore


How the cavity is configured inside the magnet bore

• One short rectangular cavity installed inside one of the two bores

• No tuning

• Longitudinally split

• Positioned and locked in all directions inside the bore. Should prevent quench forces from damaging the magnet

x

y E

TE101

Resonant power


• 𝑃 = 𝑔𝑎𝛾𝛾2𝜌𝑎

1

𝒎𝒂𝐵2𝐶𝑉𝑚𝑖𝑛 𝑄𝑐 , 𝑄𝑎

= 1.6 × 10−23W × 𝑔𝑎𝛾𝛾1014GeV

2 𝜌𝑎300 MeV/cm3

2.4 × 10−5𝑒𝑉

𝒎𝒂

×𝐵

9 T

2 𝑪

0.66

𝑉

5 𝑙

𝑄

5 × 103

• ma = 24 meV (f = 5.8 GHz)

• B = 9 T , CAST magnet

• V = 5 liters

• Q = min[Qc,Qa] = Q0/2 ~ 5,000; critical coupling • Qc loaded quality factor• Q0 cavity quality factor

Time required for a single measurement


𝑡 = 9 × 105𝑠𝑆𝑁𝑅

4

2𝑇

3.8 K

2 𝐶

0.66

−2𝐵

9 T

−4 𝑉

5 𝑙

−2

× 𝑔𝑎𝛾𝛾1014GeV

−4 𝜌𝑎

300𝑀𝑒𝑉/𝑐𝑚3

−2 2.4×10−5𝑒𝑉

𝑚𝑎

−3

×𝑄

5×103

−2 106

𝑄𝑎~ 10 days, 𝑔𝑎𝛾𝛾 = 10−14GeV−1

ma = 24 meV (f = 5.8 GHz) ; B = 9 T , CAST magnet

V = 5 liters

Q = min[Qc,Qa] = Q0/2 ~ 5,000; critical couplingQc loaded quality factorQ0 cavity quality factor

T = System Temperature = physical temperature + receiver&amplifier-chainequivalent noise temperature. Commercial HEMT amplifiers.

Projected sensitivity


CAST-CAPP Sensitivity (*)

24

(*) ADMX-HF can run in a region similar to CAST.

ADMX Target

Preliminary, assuming phase-matched

multiple cavities


The RF cavity placed inside the bore

“Inspired” by LHC beam screen design and testing , but 7 times thinner copper plating


The installed cavity

Q0 10,000


Vacuum Vessels

Necessity• Amplifier in a region with no

magnetic field• At the bore temperature (1.8 K)


Cavity instrumentation

Three axis Hall probe

HEMT Amplifier

T-sensors

Cavity

Cu Plate in Vacuum Vessel

Two-axis Hall probe


What we did

1

2 3

4

5

Cavity


The cryostat was closed July 13 2016


Importance of this installation

• First phase of CAST-CAPP project: started June 2016.

• Feasibility study

• Long magnet cycle and running schedule: needed not to miss this opportunity

• Will assess if the current cavity setup is adequate

• Learn about the RF environment inside the bore

• Evaluate cavity quality factor in running condition

• Learn about the mechanics of the cavity installation and positioning

• Whether we reach full field position

• Magnet quench issues

• ...

CAPP/IBS• Jihoon Choi RF measurements, simulations

• Woohyun Chung Cavity quality factor

• Young-Im Kim Room temperature RF

• Miran Kim Computer simulations

• ByeongRok Ko RF measurements and cryogenics

• MyeongJae Lee Data acquisition

• Soohyung Lee Slow control

• Lino Miceli

• SungWoo Youn Multi-cavity phase matching

• Yannis Semertzidis (CAPP, KAIST) CAPP Director, physics analysis

• Harry Themann Mechanical design, hardware

• Minsang You Undergraduate student

22Lino Miceli - 12th PATRAS Workshop - 20-26 June 2015, Jeju Island, South Korea

Contributors to the CAST-CAPP/IBS project29 people, 5 institutions

23

• CAST• Konstantin Zioutas CAST spokesperson• Martyn Davenport Integration with the CAST magnet • Wolfgang Funk CAST new technical coordinator• Jean-Michel Laurent Vacuum and magnet operations• Antonios Gardikiotis Stress simulations• Theodoros Vafeiadis Assistance during installation

• CERN• Michael Betz RF• Fritz Caspers RF, cavity design, and more• Lucio Fiscarelli Magnetic field measurements• Carlo Petrone Magnetic field sensing• Walter Wuensch Consultant

Lino Miceli - 12th PATRAS Workshop - 20-26 June 2015, Jeju Island, South Korea


24

• Brookhaven National Laboratory (BNL)• Joseph M. Brennan RF, cavities

• Frank Lincoln Mechanical Engineering

• Korea Advanced Institute of Science and Technology (KAIST)• Hyoungsoon Choi Low Temperatures

• Jhinhwan Lee Tuning optimization, Q enhancement

• Korea Research Institute of Standard and Science (KRISS)• Yonuk Chong Low noise amplifiers, electronics

• Yong-Ho Lee Low noise amplifiers, B-field shielding

Lino Miceli - 12th PATRAS Workshop - 20-26 June 2015, Jeju Island, South Korea


Conclusion


• The CAST-CAPP/IBS Detector project is well underway

• It expands the CAST program into DM search

• A new chapter in DM search at CERN

cold dark matter axion search with a dipole magnet · oct cern spsc committee review and approval...

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