ADMX - the Axion Dark Matter eXperiment Daniel Bowring, on behalf of the ADMX collaboration APS-DPF 2017 31 July 2017
Axions and WIMPs WIMPs scatter as quanta Axions scatter as classical waves ◮ WIMP-nucleon ◮ Coherently oscillating “clouds” scattering detector ◮ h/p ∼ 100 m strategies ◮ Phase coherent signals ∼ ms. ◮ Mass ∼ 10s-100s of GeV? ◮ µ ev < m a < meV 2 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Axion mass is only loosely constrained by theory/measurement. ◮ L aγγ = g aγγ a E · B ◮ DFSZ model for a → γγ detection relevant to DM axions. Points are predictions from theory. ◮ ADMX has demonstrated DFSZ-compatible sensitivity. 3 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Signal power and SNR drive haloscope design. � ρ a � � f a � P ≈ 0 . 5 × 10 − 21 W · 0 . 5 × 10 − 21 g · cm 3 1 GHz � � B � 2 � min( Q c , Q a ) � 2 � � � g aγγ V C × 10 5 0 . 36 500 L 7 T Dicke radiometer equation explains ◮ Signal power is limited: P ∝ B 2 V design constraints: ◮ t � 100 s for realistic run schedules � t ◮ System noise temperature T s = T phys + T N SNR = P ◮ At the quantum limit, T N → 48 mK at 1 GHz kT s ∆ f 4 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Signal power and SNR drive haloscope design. � ρ a � � f a � P ≈ 0 . 5 × 10 − 21 W · 0 . 5 × 10 − 21 g · cm 3 1 GHz � � B � 2 � min( Q c , Q a ) � 2 � � � g aγγ V C × 10 5 0 . 36 500 L 7 T Dicke radiometer equation explains ◮ Signal power is limited: P ∝ B 2 V design constraints: ◮ t � 100 s for realistic run schedules � t ◮ System noise temperature T s = T phys + T N SNR = P ◮ At the quantum limit, T N → 48 mK at 1 GHz kT s ∆ f 5 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Signal power and SNR drive haloscope design. � ρ a � � f a � P ≈ 0 . 5 × 10 − 21 W · 0 . 5 × 10 − 21 g · cm 3 1 GHz � � B � 2 � min( Q c , Q a ) � 2 � � � g aγγ V C × 10 5 0 . 36 500 L 7 T Dicke radiometer equation explains ◮ Signal power is limited: P ∝ B 2 V design constraints: ◮ t � 100 s for realistic run schedules � t ◮ System noise temperature T s = T phys + T N SNR = P ◮ At the quantum limit, T N → 48 mK at 1 GHz kT s ∆ f 6 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Signal power and SNR drive haloscope design. � ρ a � � f a � P ≈ 0 . 5 × 10 − 21 W · 0 . 5 × 10 − 21 g · cm 3 1 GHz � � B � 2 � min( Q c , Q a ) � 2 � � � g aγγ V C × 10 5 0 . 36 500 L 7 T Dicke radiometer equation explains ◮ Signal power is limited: P ∝ B 2 V design constraints: ◮ t � 100 s for realistic run schedules � t ◮ System noise temperature T s = T phys + T N SNR = P ◮ At the quantum limit, T N → 48 mK at 1 GHz kT s ∆ f 7 D. Bowring | ADMX - the Axion Dark Matter eXperiment
ADMX Overview ◮ 500 MHz - 1 GHz cavity ◮ 7 T solenoid ◮ 3 He- 4 He dilution refrigerator ◮ SQUID amplifiers 50 cm 8 D. Bowring | ADMX - the Axion Dark Matter eXperiment
ADMX cold electronics diagram S 21 line S 11 line to receiver 300 K -20 dB -20 dB HFETs hot load 4 K 300 mK -20 dB -20 dB C2 DC block 50 Ω Cavity MSA (150 mK) C1 9 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Quantum-limited amplifiers ◮ MSA = microstrip SQUID amplifier; JPA = Josephson Parametric Amplifier ◮ Recall SNR ∝ 1 /T s . 10 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Quantum-limited amplifiers issue ≥ 1 photon of noise per resolved mode. C. Caves, 1982 D. Kinion and J. Clarke, Appl. Phys. Lett. 98 , 202503 (2011). 11 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Characterization of noise temperature 12 D. Bowring | ADMX - the Axion Dark Matter eXperiment
ADMX operations overview 1. Scan cavity frequency, integrate each frequency bin to desired SNR 2. Power above trigger threshold? Bin flagged as axion candidate. 3. Rescan candidates 4. Detection committee reviews persistent > 3 σ candidates: ◮ Switch to resonant mode with poor axion coupling ◮ Attenuate B -field (recall P ∝ B 2 ) ◮ Blind signal injection 13 D. Bowring | ADMX - the Axion Dark Matter eXperiment
First axion search at DFSZ sensitivity! 14 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Projected ADMX-G2 discovery potential 15 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Projected ADMX-G2 discovery potential Current experiment operates at DFSZ sensitivity in 500 MHz-1 GHz range. 16 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Projected ADMX-G2 discovery potential ADMX “sidecar” cavity used to test piezo tuning. TM 010 mode can probe 4-6 GHz, TM 020 mode can probe 6-7 GHz. 17 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Projected ADMX-G2 discovery potential Fabrication underway for 4-cavity array, 1-2 GHz. 18 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Projected ADMX-G2 discovery potential Fermilab concept for ≥ 2 GHz cavity. 19 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Quantum computing technology may be the path to � 10 GHz searches. Quantum nondemolition measurements with solid-state qubits allow us to count single photons, beat the standard quantum limit. Qubit coupled to 10 GHz cavity Akash Dixit, (UC student, funding from Heising-Simons Foundation, talk on Tuesday, 1:50 pm, IARC . Please visit our new and growing lab at SiDet this Friday! 20 D. Bowring | ADMX - the Axion Dark Matter eXperiment
Thanks for your attention! ADMX Collaboration: U. Washington, U. Florida, LLNL, UC-Berkeley, PNNL, LANL, NRAO, Washington U., Sheffield U., FNAL This work is supported by U.S. Department of Energy Office of Science, Office of High Energy Physics, under awards DE-SC00098000, DE-SC0011665, DE-AC52-07NA27344, and DE-AC03-76SF00098, the Heising-Simons Foundation, and the Laboratory-Directed Research and Development programs at Fermi National Accelerator Laboratory, Lawrence Livermore National Laboratory, and Pacific Northwest National Laboratory. 21 D. Bowring | ADMX - the Axion Dark Matter eXperiment
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