DANAE - a new experiment for direct dark matter detection using RNDR DEPFET detectors Hexi Shi HEPHY ÖAW 11 April 2018 DEPFET workshop Schloss Ringberg
DANAE (DANAË) Direct dArk matter search using DEPFET with repetitive- Non-destructive-readout Application Experiment OeAW funding for detector technology “Danae” by G. Klimt Collaboration A. Bähr A, J. Ninkovic A, J. Treis A, H. Kluck B,C, J. Schieck B ,C, H. Shi B, Max-Planck-Gesellschaft Halbleiterlabor, Germany A, Institut für Hochenergiephysik der Österreichischen Akademie der Wissenschaften, Vienna, Austria B, Atominstitut, Technische Universität Wien, Vienna, Austria C
The project overview Direct Dark Matter Detection with DEPFET − 35 10 ] 2 [cm • minimal reach for nuclear recoil experiments 36 − 10 e σ CRESST about few 100 MeV nuclear recoil − 37 10 excluded by Xenon10 excluded by Xenon100 38 − 10 • dark matter electron scattering offers 39 − 10 − 40 reach towards MeV dark matter 10 − 41 10 - E =2e , 0 background events, 1.0 kg ⋅ y T − 42 10 - • measurement of low noise ionisation signal E =2e , 3 background events, 3.0 kg y ⋅ T - E =1e , 3 background events, 1.0 kg y ⋅ 43 T − 10 - E =2e , 3 background events, 1.0 kg ⋅ y in low background environment T − 44 10 3 2 10 10 10 m [MeV] χ • RNDR DEPFET sensors developed by * semiconductor laboratory of MPG σ =0.21 e - σ = 0 ,21 e- 60 • setup for proof-of-principle Without laser (Noise peak) 50 Weak laser (poissonian photon distribution) Gauss fit to noise peak 40 Counts measurement currently prepared 30 20 10 • expect first results early 2019 0 -1 0 1 2 3 4 5 6 Pulseheight (# Electrons) EPJ C, 77(12), 279 (2017) 15 more information: arXiv :1706.08666 *Repetitive Non-Destructive Readout from Jochen Schieck 3 “Experimental Dark Matter Search at HEPHY”
Dark matter landscape - partly Over 80% of the mass in the universe is invisible dark matter “WIMP” as a dark matter candidate : Credit: NASA / WMAP Science Team - weakly interacting with matter < σ WIMP ・ v> ∼ G F2 ・ m Χ 2 ∼ 1/ Ω Χ 1 keV 1 MeV 1 GeV 1 TeV - fits the Hubble constant and “relic” ~ ~ density of dark matter WIMPs dominated the direct predicts dark matter WIMP mass detection experiments between 2 GeV and 120 TeV until recently 4
WIMP direct detection method look for nuclear recoils from WIMP-nucleus scattering DM DM Detection limitation : light e - e - phono energy deposit from nucleus recoil electri nucleus nucleus E NR ~ 2 μ χ ,N2 v χ /m N ● -> for 100 MeV m χ , E NR ~ 1 eV * image credit R. Essig plus quenching factors and Energy deposit in target noise level of the detectors material in forms of : - light typical DM velocity v χ . 800 km / s - phonon *for silicon - electric charge 5
DM-nucleus scattering direct search status 1 GeV/c 2 6 arXiv:1711.07692
DM-nucleus scattering direct search status weak interaction scale 1 GeV/c 2 no evidence for WIMP yet 6 arXiv:1711.07692
DM-nucleus scattering direct search status DAMIC CDMS weak interaction scale 1 GeV/c 2 no evidence for WIMP yet 6 arXiv:1711.07692
Dark Sector and Light Dark Matter 1 keV 1 MeV 1 GeV 1 TeV ~ ~ Dark sectors Dark sector : WIMPs interaction between DM and (DM + new mediators) standard model particle several sharp “theory” targets mediated by a dark photon (freeze-out, asymmetric, freeze-in, SIMP , ELDER) (one example of mediators) DM DM χ χ clear predictions from g χ A ʹ , Φ multiple models over wide DM mass region, including keV ~ GeV range SM SM -> comparable observables DM scattering in experiments image credit R. Essig 7
DM-electron scattering kinematically DM to overcome binding energy Δ E DM need need > ∆ E e - nucleus nucleus v DM . 800 km / s = ⇒ e - image credit R. Essig O(100 keV) JHEP05(2016)046 8
DM-electron scattering kinematically DM to overcome binding energy Δ E DM need need > ∆ E e - nucleus nucleus v DM . 800 km / s = ⇒ e - image credit R. Essig O(100 keV) bound e - does not have definite momentum, typical momentum transfer is set by e - not by DM. (for outer shell electron) transferred energy: typical Δ E e ~ 4 eV recoil energy JHEP05(2016)046 ΔΕ 8
Target materials for electron recoils Target m χ E th Examples Status Timescale Type threshold Noble ~ 10 Done w data; improvements Xe, Ar, He ~ 5 MeV existing possible liquids eV Semi- ~ 1 (E th ~ 40 eV SuperCDMS, DAMIC ) Ge, Si ~ 200 keV ~ 1-2 years E th ~ 1eV SENSEI , DEPFET R&D conductors eV Scintillators GaAs, NaI, ~ 1 ≲ 5 years ~ 200 keV R&D required CsI, … eV ~ 1 R&D required ≲ 5 years Supferfluid He ~ 1 MeV unknown background eV Super- ~ 1 ~ 10 - 15 R&D required Al ~ 1 keV unknown background conductor meV years arXiv:1608.08632 9
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�� �� �� ������� �� �� ���� � �� � ��� �� � � � � �� �� � �� ��� �� � � ��� �� �� � ���� ���� �� �� �� �� �� �� �� � �� ��� �� Application of Silicon detector DAMIC nucleus recoil CCD, with physics results y x DAMIC Ω μ z 1 GeV/c 2 Physics Procedia 61 (2015) 21 – 33 Readout noise determines threshold of ~ 11 e - (or ~ 40 eV) For O(MeV) DM-electron scattering, required threshold : O(e - ) Sub-electron noise level necessary 10 σ σ
Skipper CCD for SENSEI DAMIC CCD with repetitive readout from SENSEI homepage Readout noise : 1 sample : 3.55 e - rms 4k samples : 0.068 e - rms @ 140 K expected dark current (from DAMIC CCD) : < 10 -3 e - /pix/day 11 PRL 119(1) 131802 (2017)
SENSEI first result from a surface run 4 10 Active mass : 0.071 grams Exposure: 0.019 gram-days 427 minutes exposure (0.33 g-hr) 3 10 above sea level 220 m Entries 2 10 single read noise : ~ 4 e - effective noise : ~ 0.14 e - (800 repetitions) 10 dark current : ~1.14 e - /pixel/day assume all events DM induced 1 -> conservative limit -1 10 1 2 3 4 5 6 - Charge [e ] arXiv:1804.00088v1 ultralight dark photon mediator DM-electron cross section DM-electron cross section �� �� �� - �� � �� =( α � � / � ) � � �� α � � � �� �� �� - �� �� �� � � � �� - �� �� �� � �� - �� = � �� �� � � � � � � = � �� - �� �� �� ������ | � � | = � � | �� �� �� - �� � � | � � � � � � � � � � - � � � � � � �� �� � �� - �� � � ���������� ����������� � � �� �� � � | �� - �� σ � [ �� � ] ������ σ � �� � � � | = | �� �� | � � � | Freeze-In ����� ����������� � � � � � �� - �� � � � � � � � - � � � � � � �� �� � �� - �� �� �� �� - �� �� �� �� - �� �� �� �� - �� �� �� ������� �� �� �� - �� �� �� � � - � � �� - �� � � - ������� � � �� �� �� - �� � � - � � liquid Xenon �� �� � � - � � �� - �� �� �� �� - �� � �� �� � �� � � �� �� � �� � � χ ��� � χ [ ��� ] 12 arXiv:1804.00088v1 from SENSEI homepage
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