Status of ALPS II Mikhail Karnevskiy 1 1 DESY 85. Physics Research - - PowerPoint PPT Presentation

Status of ALPS II

Mikhail Karnevskiy1

1DESY

• 85. Physics Research Committee, 08.05.2018

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 1 / 18

Motivation

The Standard Model of particle physics

◮ Describes three of the four fundamental forces ◮ Explains a wide variety of experimental results

Dark matter Astronomical hints

◮ TeV transparency of the universe ◮ Energy loss in stars at different evolution stages

JCAP05(2016)057

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 2 / 18

SM extension and ALP

Extension of the Standard model: singlet complex scalar σ featuring a global U(1) symmetry, which is spontaneously broken at the scale Vσ ≫ V = 246 GeV

αs 8πCag a Vσ G c µν ˜

G cµν − α

8πCaγ a Vσ Fµν ˜

F µν + 1

2Caf ∂µa Vσ ¯

φf γµγ5ψf

Axion:

◮ Solves the strong CP-problem ◮ Acts as CP conserving dynamic field

Axion like particles (ALPs):

◮ Similar to axions with different couplings ◮ Can explain different observations ◮ Can be dark matter Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 3 / 18

ALPs hints

• Phys. Rev. D 87, 035027 (2013)

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Axion mass ma [eV]

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Axion coupling gaγ [GeV−1 ]

Cold dark matter

Low opacity hints HB Cooling

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 4 / 18

Experiments looking for ALPs

Light shining through a wall (LSW):

◮ ALPs are produced and detected

in the lab

Helioscopes:

◮ ALPs are produced in the sun,

but converted to photons and detected in the lab

Haloscopes:

◮ Local dark matter halo ALPs

interact with the experiments magnetic field

Astronomical observations:

◮ ALPs are produced and converted

back to photons in the universe ALPS web page; IAXO CERN-SPCS-2013-022; ADMX web page

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 5 / 18

ALPS II Introduction

Search for ALP Light-shining-through-a-wall concept:

◮ 30W, 1064 nm laser source ◮ Two 100m optical cavities surrounded by 10 dipole HERA magnets each ◮ 150 kW circulating power in the PC ◮ Power build-up of 40 000 in the RC ◮ Two detector options: Single photon counting, heterodyne detector

Location: DESY Hamburg, HERA-Hall north.

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 6 / 18

ALPS II sensitivity

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ALPSII

CAST

SN87A FermiLAT

Cold dark matter

ADMX

HESS

Chandra

Low opacity hints

HB Cooling

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 7 / 18

ALPS collaboration

ALPS II collaboration organization has changed from the former R&D phase towards a project to set up ALPS II ALPS II has been considerably strengthened by experienced DESY people

◮ Project office ◮ Cryogenics and magnet string ◮ Installation of clean rooms ◮ Technical coordination ◮ Safety, including laser safety Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 8 / 18

ALPS project

Project structure of the ALPS II have been formalised, including work breakdown structure, review and approval procedure. Conceptual design reports are prepared and corresponding internal reviews are

• rganized for.

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 9 / 18

Tests of optical system. Key points.

Keep both optical cavities in resonance

◮ PC: actuation of Laser frequency ◮ RC: actuation of mirror position

Precise alignment of both cavities

◮ < 5µrad precision of mirror alignment over weeks

No possibility to distinghish between IR laser light and reconverted axion:

◮ Use green light to perform cavity lock ◮ No IR light from PC to RC (dichroick window, light tightness) ◮ Filter green from IR signal Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 10 / 18

Optical system. Current status

Stable frequency lock of the PC

◮ 30 W × 1650 ∼ 50 kW ◮ Build-up factor of 4000 at low power

Length lock of the RC

◮ Build-up factor of 31000 ◮ Actuation speed up to 5 kHz ◮ Length stabilisation down to 0.5 pm ◮ Possible to lock without additional seismic isolation

Differences in cavity length for green and IR is under studies

◮ Temperature induced changes in effective point of reflection between IR and

green are under investigation

◮ Customized mirror coatings were designed and are being tested Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 11 / 18

Optical system. Next steps

Demonstration of dual resonance: Operate both cavities simultaneously, mitigate effective point of reflection changes Demonstration long term alignment stability of both cavities with respect to each other Light tightness Integration of detector system Timeline: ALPS II data runs in 2020

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 12 / 18

Transition-Edge-sensor detector.

Microcalorimeter measuring temperature change using superconductive tungsten chip and SQUID readout

t t t RTES ITES Vout

R0=0.3RN I0

t TTES

T0 Vp~60mV

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 13 / 18

TES Detector. Progress and plans.

First detector prototype have been studied using ADR cryosystem.

◮ Only 20 h continuous operation ◮ Unstable machine

New detector module have been assembled at PTB and ready for installation. New dilution refrigerator was manufactured and will be delivered to DESY next week. Measured background rate is 10−2 Hz

◮ Largest component found to be from

black body radiation

◮ Filter bench to filter black body is

under testing

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 14 / 18

Heterodyne Detector.

An interference between weak measured signal and strong local oscillator creates observable beat note. Phase relation between local oscillator and measured signal is fixed When the regenerated photons are coherent with the local oscillator, the signal will integrate up over time Dedicated test at the UF: 2 weeks stable data run S = [ESei(ω1t+φ) + ELOeiω2t]2 = = E 2

LO + 2ELOES cos(Ωt + φ)

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 15 / 18

Magnet system

Dipole HERA magnets: 600m radius of curvature, 5.3 T. For ALPS II they have to be unbent to provide enough free aperture (> 40 mm). 9 magnets were successfully unbent, tested and ready to be used.

◮ Stable long-term operation at 5.3 T ◮ Free aperture between 47 mm and 50 mm

Magnet preparation work reaches a full speed of 1 magnet per month.

cold mass pressure screw pressure props

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Tunnel and infrastructure

The removal of accelerator components in the straight section HERA North required for the installation of the ALPS II experiment started by the end of March 2018. Refurbishment of the cryogenic has been started Clean rooms and vacuum tanks are under design

Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 17 / 18

Summary

Astronomical observations strengthened the motivation for the ALPS II experiment. We are moving from R&D towards to construction phase. Active tunnel work have been started. Several DESY experts joined ALPS collaboration to strengthen the project phase.

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