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

Status of ALPS II Mikhail Karnevskiy 1 1 DESY 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 V σ ≫ V = 246 GeV F µν + 1 µν ˜ G c µν − α V σ F µν ˜ ∂ µ a V σ ¯ α s V σ G c a a φ f γ µ γ 5 ψ f 8 π C ag 8 π C a γ 2 C af 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) -5 10 -6 10 -7 10 Axion coupling g aγ [GeV − 1 ] Low opacity hints -8 10 -9 10 -10 10 HB Cooling -11 10 -12 10 -13 10 -14 10 Cold dark matter -15 10 -16 10 -17 10 -14 -12 -10 -8 -6 -4 -2 0 10 10 10 10 10 10 10 10 Axion mass m a [eV] 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 -5 10 -6 10 -7 10 Axion coupling g aγ [GeV − 1 ] Low opacity hints -8 CAST 10 -9 10 -10 10 ALPSII HESS HB Cooling FermiLAT -11 10 SN87A Chandra -12 10 ADMX -13 10 -14 10 Cold dark matter -15 10 -16 10 -17 10 -14 -12 -10 -8 -6 -4 -2 0 10 10 10 10 10 10 10 10 Axion mass m a [eV] 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 organized 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 ◮ < 5 µ rad 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 TES T 0 t R TES R 0 =0.3R N I TES t I 0 t V out t V p ~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 = [ E S e i ( ω 1 t + φ ) + E LO e i ω 2 t ] 2 = = E 2 LO + 2 E LO E S cos(Ω t + 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. pressure screw cold mass pressure props Mikhail Karnevskiy Status of ALPS II 85’th PRC, 08.05.2018 16 / 18

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