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Demonstrating Electromagnetic Properties of a MADMAX prototype booster Jacob Egge for the MADMAX collaboration 1 Axions MADMAX: MA gnetised D isk-and- M irror A xion e X periment Solution to the strong CP problem Dark matter candidate

SLIDE 1

1

Demonstrating Electromagnetic Properties of a MADMAX prototype booster

Jacob Egge

for the MADMAX collaboration

SLIDE 2

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

2

Axions

Solution to the strong CP problem
Dark matter candidate

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

Credit: A. Ringwald

SLIDE 3

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

3

Basic Principle

P/ A=2.2×10

−27 W m −2( Be

10T )

C aγ

2 ⋅f (ϵ1,ϵ2)

tiny power → boost needed

SLIDE 4

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

4

Basic Principle

Solution: Use many discs

Resonance and constructive interference
f emissions

Boost factor (β2) simulation

P/ A=2.2×10

−27 W m −2( Be

10T )

C aγ

2 ⋅f (ϵ1,ϵ2)⋅β 2

Power of booster Power of singlemirror

SLIDE 5

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

5

20 Disc Setup

Mirror Sapphire Discs

SLIDE 6

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

6

20 Disc Setup

20 disc seed setup
No magnetic field
Test electromagnetic

response with a Vector Network Analyzer

Vector Network Analyzer Antenna Parabolic Mirror Copper Mirror

SLIDE 7

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

7

One Disc System

System characterization via Group Delay:

τg=− d ϕ d ω

Phase Angular Frequency

SLIDE 8

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

8

Mechanical Precision

Thermal expansion changes disc

distance

Command motor to the same position

coming from different directions Temperature Response Motor Hysteresis

SLIDE 9

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

9

Reflections

Additional unwanted

reflections in the system

antenna mismatch,

surroundings, ...

Removal by time gate
But: In a many discs

system signal and unwanted reflections

verlap

Mirror only

Mirror Peak Secondary Reflections 1 2 3

SLIDE 10

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

10

Reflections

→ Necessary to model additional reflections

τ=12ns τ=10 ns τ=8.7ns τ=7 ns

One disc system

SLIDE 11

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

11

Reflections

Measurement Mirror only Idea: Include reflections in simulation

SLIDE 12

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

12

Reflections

Measurement Simulation Mirror only Idea: Include reflections in simulation

SLIDE 13

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

13

Reflections

Mirror only

Simulation reproduces group

delay reasonably well

Uncertain behavior for many

discs

preliminary

SLIDE 14

Mar 22 2018

MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

14

Conclusion and Outlook

12ns

Mechanical precision of μm
Reflections cause problems
Effect of disc tilts

→ Automatic tilting

Absolute positioning

→ Interferometer

Losses