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Status of NEMO 3 and SuperNEMO project

Status of NEMO 3 and SuperNEMO project. F. Piquemal ILIAS Meeting Orsay 2005/04/14. Current status of NEMO 3 SuperNEMO: Description of the project Improvements R&D program. Fabrice Piquemal IDEA meeting – Orsay April,2005. Status of NEMO 3 experiment.

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Status of NEMO 3 and SuperNEMO project

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  1. Status of NEMO 3 and SuperNEMO project F. Piquemal ILIAS Meeting Orsay 2005/04/14 Current status of NEMO 3 SuperNEMO: Description of the project Improvements R&D program Fabrice Piquemal IDEA meeting – Orsay April,2005

  2. Status of NEMO 3 experiment Neutrino Ettore Majorana Observatory NEMO collaboration CENBG, IN2P3-CNRS et Université de Bordeaux, France IReS, IN2P3-CNRS et Université de Strasbourg, France LAL, IN2P3-CNRS et Université Paris-Sud, France LPC, IN2P3-CNRS et Université de Caen, France LSCE, CNRS Gif sur Yvette, France Fes University, Marocco Charles University, Czech Republic IEAP, CTU Prague, Czech Republic INL, Idaho Falls, USA MHC, Massachusets ,USA ITEP, Moscou, Russia JINR, Dubna, Russia Kurchatov Institute, Russia Jyvaskula University, Finland Saga University, Japan UCL London, UK ISMA Kharkov, Ukraine 17 institutions 10 countries ~ 45 physicists Fabrice Piquemal IDEA meeting – Orsay April,2005

  3. 20 sectors B(25 G) 3 m Magnetic field: 25 Gauss Gamma shield: Pure Iron (18 cm) Neutron shield: borated water + Wood 4 m Able to identify e-, e+, g and a The NEMO3 detector Fréjus Underground Laboratory : 4800 m.w.e. Source: 10 kg of  isotopes cylindrical, S = 20 m2, 60 mg/cm2 Tracking detector: drift wire chamber operating in Geiger mode (6180 cells) Gas: He + 4% ethyl alcohol + 1% Ar + 0.1% H2O Calorimeter: 1940 plastic scintillators coupled to low radioactivity PMTs Background:natural radioactivity, mainly 214Bi et 208Tl (g 2.6 MeV) Radon, neutrons (n,g), muons, bb(2n) Fabrice Piquemal IDEA meeting – Orsay April,2005

  4. NEMO 3 is running since February,2003 in Modane laboratory Fabrice Piquemal IDEA meeting – Orsay April,2005

  5. bb2n measurement bb0n search bb decay isotopes in NEMO-3 detector 116Cd405 g Qbb = 2805 keV 96Zr 9.4 g Qbb = 3350 keV 150Nd 37.0 g Qbb = 3367 keV 48Ca 7.0 g Qbb = 4272 keV 130Te454 g Qbb = 2529 keV External bkg measurement natTe491 g 100Mo6.914 kg Qbb = 3034 keV 82Se0.932 kg Qbb = 2995 keV Cu621 g (All enriched isotopes produced in Russia) Fabrice Piquemal IDEA meeting – Orsay April,2005

  6. Transverse view Run Number: 2040 Event Number: 9732 Date: 2003-03-20 Transverse view Run Number: 2040 Event Number: 9732 Date: 2003-03-20 Longitudinal view Longitudinal view 100Mo foil Vertex emission Geiger plasma longitudinal propagation 100Mo foil Vertex emission Deposited energy: E1+E2= 2088 keV Internal hypothesis: (Dt)mes –(Dt)theo = 0.22 ns Common vertex: (Dvertex) = 2.1 mm Scintillator + PMT (Dvertex)// = 5.7 mm • Trigger: at least 1 PMT > 150 keV •  3 Geiger hits (2 neighbour layers + 1) • Trigger rate = 7 Hz • bb events: 1 event every 2.5 minutes Criteria to select bb events: Side view • 2 tracks with charge < 0 • 2 PMT, each > 200 keV • PMT-Track association • Common vertex • Internal hypothesis (external event rejection) • No other isolated PMT (g rejection) • No delayed track (214Bi rejection) Top view bb events selection in NEMO-3 Typical bb2n event observed from 100Mo Fabrice Piquemal IDEA meeting – Orsay April,2005

  7. Data • Data 22 Monte Carlo 22 Monte Carlo Background subtracted Background subtracted 100Mo 22 preliminary results (Data Feb. 2003 – Dec. 2004) Angular Distribution Sum Energy Spectrum 219 000 events 6914 g 389 days S/B = 40 219 000 events 6914 g 389 days S/B = 40 NEMO-3 NEMO-3 100Mo 100Mo E1 + E2 (keV) Cos() 7.37 kg.y T1/2 = 7.14 ± 0.02 (stat) ± 0.54 (syst)  1018 y

  8. 100Mo 22 Single Energy Distribution HSD, higher levels contribute to the decay 1 SSD, 1 level dominates in the decay (Abad et al., 1984, Ann. Fis. A 80, 9) 100Tc 0 100Mo 4.57 kg.y E1 + E2 > 2 MeV 4.57 kg.y E1 + E2 > 2 MeV • Data • Data Esingle (keV) Single electron spectrum different between SSD and HSD Simkovic, J. Phys. G, 27, 2233, 2001 Esingle (keV) NEMO-3 NEMO-3 22 SSD Monte Carlo 22 HSD Monte Carlo SSD Single State HSD higher levels Background subtracted Background subtracted /ndf = 40.7 / 36 /ndf = 139. / 36 Esingle (keV) HSD: T1/2 = 8.61  0.02 (stat)  0.60 (syst)  1018 y SSD: T1/2 = 7.72  0.02 (stat)  0.54 (syst)  1018 y 100Mo 22 single energy distribution in favour of Single State Dominant (SSD) decay

  9. Data 22 Monte Carlo Data Data Data 22 preliminary results for other nuclei NEMO-3 932 g 389 days 2750 events S/B = 4 82Se T1/2 = 0.98 ± 0.2 (stat) ± 0.1 (syst)  1020 y 116Cd T1/2 = 2.8 ± 0.1 (stat) ± 0.3 (syst)  1019 y 150Nd T1/2 = 9.7 ± 0.7 (stat) ± 1.0 (syst)  1018 y 96ZrT1/2 = 2.0 ± 0.3 (stat) ± 0.2 (syst)  1019 y 82Se Background subtracted Background subtracted E1+E2 (keV) NEMO-3 NEMO-3 NEMO-3 37 g 168.4 days 449 events S/B = 2.8 405 g 168.4 days 1371 events S/B = 7.5 5.3 g 168.4 days 72 events S/B = 0.9 116Cd 96Zr 150Nd bb2n simulation bb2n simulation bb2n simulation E1+E2 (MeV) E1+E2 (MeV) E1+E2 (MeV)

  10. Background Measurement External Background 208Tl (PMTs) Measured with (e-, g) external events ~ 10-3bb0n-like events year-1 kg -1 with 2.8<E1+ E2<3.2 MeV ExternalNeutrons and High Energy gamma Measured with (e-,e-)int or (e+,e-) events with E1+E2> 4 MeV  0.02 bb0n-like events year-1 kg -1 with 2.8<E1+ E2<3.2 MeV 208Tl impurities inside the foils ~ 60 mBq/kg Measured with (e-,2g), (e-,3g) events coming from the foil ~ 0.06 bb0n-like events year-1 kg -1 with 2.8<E1+ E2<3.2 MeV 214Bi impurities inside the foils Measured with (e-,g,a) events coming from the foil, dominated by radon in first period Radon supressed since December 2004, measument in progress.Limits from Ge: A(214Bi)< 400 mBq/kg < 0.1 bb0n-like events year-1 kg -1 with 2.8<E1+ E2<3.2 MeV 100Mo bb2n decay T1/2 = 7.14 1018 y ~ 0.3 bb0n-like events year-1 kg -1 with 2.8<E1+E2<3.2 MeV Fabrice Piquemal IDEA meeting – Orsay April,2005

  11. Limit on the Majorana neutrino effective mass 100Mo: T1/2(bb0n) > 4.6 1023 y 82Se: T1/2(bb0n) > 1.9 1023 y mn < 0.6 – 1.0 eVmn < 1.3 – 3.6 eV NME Ref: Simkovic et al., Phys. Rev. C60 (1999) Stoica, Klapdor, Nucl. Phys. A694 (2001) Simkovic et al., Phys. Rev. C60 (1999) Stoica, Klapdor, Nucl. Phys. A694 (2001) Caurier et al., Phys. Rev. Lett. 77 1954 (1996) Previous limits: T1/2(bb0n) > 5.5 1022 ymn < 5 eV Elliot et al. (1992) Previous limits: T1/2(bb0n) > 5.5 1022 ymn < 2.1 eV Ejiri et al. (2001) 100Mo 82Se Limit on the effective mass of the Majorana neutrino, on Majoron and on V+A (limits @ 90% CL) Limit on Majoron 100Mo: T1/2 (bb0nM) > 1.8 1022 y 82Se: T1/2 (bb0nM) > 1.5 1022 y gM < (5.3 – 8.5) 10-5(best limit) gM < (0.7 – 1.6) 10-4 Simkovic (1999), Stoica (1999)Simkovic (1999), Stoica (2001) • Limit on V+A • 100Mo: T1/2 (bb0n V+A) > 2.3 1023 y 82Se: T1/2 (bb0n V+A) > 1.0 1023 y • l < (1.5 – 2.0) 10-6l < 3.2 10-6 • Tomoda (1991), Suhonen (1994) Tomoda (1991) Fabrice Piquemal IDEA meeting – Orsay April,2005

  12. Arbitrary unit Radon free air purification system A(222Rn) in the LSM ~ 20 Bq/m3 Inside NEMO 3 ~ 20 mBq/m3 (measured by NEMO 3 itself and radon detectors developed by the collaboration sensitive to 1mBq/m3 ) Too high background May 2004 :Tent surrounding the detector October 2004 : Radon-free SuperKamiokande-like Air Factory (2500 kg charcoal @ -50oC) December 2004 A(222Rn) ~ 0.1 Bq/m3 in the tent reduction factor ~200 Inside NEMO 3 ~ 3 mBq/m3 Reduction factor of Radon Backgound ~ 7 Work in progress to reach factor 10 Fabrice Piquemal IDEA meeting – Orsay April,2005

  13. 2008 - 2009 6914 g of 100Mo T1/2() 4 1024 y (90% C.L.) m < 0.20 – 0.35 eV 932 g of 82Se T1/2() 8 .1023 y (90% C.L.) m < 0.65 – 1.8 eV NEMO-3 Expected sensitivity Background External Background: negligible Internal Background:208Tl : 60 Bq/kg for 100Mo 300 Bq/kg for 82Se 214Bi : < 300 Bq/kg ~ 0.1 count kg1 y 1with 2.8<E1+E2<3.2 MeV : T1/2 = 7.14 1018 y ~ 0.3 count kg1 y 1with 2.8<E1+E2<3.2 MeV F. Piquemal (CENBG)CS IN2P3 2005/03/05

  14. What have we learnt with NEMO 3 detector • - to identify and measure all sources of background, • to control internal and external backgrounds at the level • of 10 kg of enriched isotopes • to build a very low-background detector, • - to provethe reliability of the chosen techniques, • -to purify bb isotopes by removing 214Bi and 208Tlcontaminants, • -to remove background due to radon, • -to develop ultra low background HPGe detectors • to gain expertise in developping radon detectors sensitive to 1 mBq/m3. • Technique can be extrapolated for larger mass detector Fabrice Piquemal IDEA meeting – Orsay April,2005

  15. SuperNEMO project Factor 100 on the bb(0n) period T1/2, reach 2 1026 years Light Majorana neutrino exchange: <mn> ~50 meV Technics à la NEMO:Source + tracking volume + calorimeter Capability to identify electrons and to measure single electron spectrum and angular correlations To reach the goal, the main improvements are: To increase the mass To reduce the internal contaminations in 208Tl and 214Bi To improve the energy resolution To improve the efficiency Fabrice Piquemal IDEA meeting – Orsay April,2005

  16. SuperNEMO preliminary design Plane geometry Source (40 mg/cm2) 12m2 , tracking volume (~3000 channels) and calorimeter (~1000 PMT) Modular (~5 kg of enriched isotope/module) 100 kg: 20 modules ~ 60 000 channels for drift chamber ~ 20 000 PMT 4 m 1 m 5 m Top view Side view Fabrice Piquemal IDEA meeting – Orsay April,2005

  17. Choice of the isotope: 82Se T1/2 ~ 1020 y (to decrease background from bb(2n) ) Qbb = 2.998 MeV Possible to produce ~100 kg with reasonnable cost and delay Possibility of distillation at the end of the enrichment process Chemical purification process similar to the purification of 100Mo used in NEMO 3 To increase the mass of the isotope:~100 kg (at least !)  7.3 1026 nuclei Ultimate sensitivy for 5 years without background T1/2 > 2.5 1027x efficiency/Nexcluded y To decrease the background from internal contaminations in 208Tl and 214Bi to obtain <1 evt/100kg/year Currently in NEMO 3 with chemical purification we obtain for 100Mo: 208Tl ~60 mBq/kg remarks: - measurement done during the « radon period », so contribution from thoron is not excluded - the mylar used as support for the source as a very small contamination in 208Tl (measured with Ge) 214Bi < 400 mBq/kg from Ge measurements remarks: not yet measured by NEMO 3 because of the radon, will be measure very soon. The SuperNEMO requirements for 100 kg obtained by simulations are: 2 mBq/kg in 208Tland10 mBq/kg in 214Bi Fabrice Piquemal IDEA meeting – Orsay April,2005

  18. How to reach these levels ? • To check the radiopurity at each step of the production  it implies to know were is produced the • isotope and to have direct contact with the company • - In case of 82Se, it can be distillated after the last step • Chemical or physical purification can be used • For chemical method, the main problem is to obtain very pure chemical products. In principal, the • extraction factor is constant and does not depend on the initial concentration. It means that the radiopurity • level can be obtain by processing several time the batch. • For physical method, it is done by making crystals. • From the experience of NEMO 3, the chemical method seems to be more appropriate • How to measure such low activity levels ? • For NEMO 3, the contaminations of the source was measured at each step (production,chemical • purification and source production) with 400 cm3 Ge detector developed with Canberra-Eurysis company • The sensitivity for 1 month measurement and 1 kg is: 60 mBq/kg in 208Tl and 200 mBq/kg in 214Bi • A gain of a factor 10 possible by increasing the size of the detector up to 1000 cm3 , by reducing the • background (needs to select new materials for both cryostat and shielding) and by changing mechanics to • measure few kg instead of 1 kg • But it will be difficult for Ge detector to validate 2 mBq/kg in 208Tl and 10 mBq/kg in 214Bi Fabrice Piquemal IDEA meeting – Orsay April,2005

  19. Mass spectroscopy could be used but only a small quantity can be measured and it is a destructive method Study of a dedicated detector based on tracko-calo method optimized for contamination measurement. To measure source foil before introduction in the modules This detector could allow also to discriminate between an homogeneous contamination of the Source and « hot spot » A possible idea: scintillator e- Source foil a Tracking volume Requirements for radon: 0.1 mBq/m3 Selection of materials to avoid radon degazing inside the detector To check the quality of the gaz for the tracking detector To protect detector against radon diffusion To have free radon air in the lab, need factory. Radon detectors for NEMO 3 sensitive to 1 mBq/m3. Based on the collection of Po ions on a Si diode in a volume of 70 l. Can be extrapolate at 1000 l and by using low background Si diode 0.1 mBq/kg could be reached. Other possibilities are under study (per example detection of Bi-Po decay in a tracking volume or liquid scintillator). Fabrice Piquemal IDEA meeting – Orsay April,2005

  20. To improve the energy resolution to decrease background from bb(2n) In a tracko-calo, the contributions to the energy resolution are : Source foil, per example 40mg/cm2 6% (FWHM) at 3 MeV Energy loss in the tracking volume Energy resolution of the calorimeter In NEMO 3, the main contribution is the calorimeter (8-9 % at 3 MeV) In SuperNEMO the objective is to be dominated by the source contribution Resolution of the calorimeter must be ~4% (FWHM) at 3 MeV The choice is to use plastic scintillator (low backscattering, very pure, low cost) coupled to photomultiplier (liquid scintilator will be also studied) Improvement of light yields, optimization of light collection (geometry of plastic, wrapping), improvement of PMT (good energy resolution and good timing),… Bigger scintillator blocs and PMT to reduce the number of channels We must keep a good efficiency to detect g-rays. Depending of the result of the R&D, there are 2 options: 10 cm thickness for the scintillator to detect both electrons and gamma or 2 cm thickness scintillator for electron + 10 cm scintillator on the backside to detect gamma. Developpement of low radioactivity PMT is needed in order to be able to measure nuclei like 130Te or 76Ge. In case of 82Se source, 2.6 MeV from 208Tl in PMT glass does not contribute to the background. With a source foil of 40 mg/cm2 and 4% at 3 MeV for the calorimeter: ~10 background events in 5 years for 100 kg from the bb(2n) Fabrice Piquemal IDEA meeting – Orsay April,2005

  21. To improve efficiency • In NEMO 3, the efficiency is 15 % due to: • - Backscattering of electron in plastic scintillator • - Diffusion on the wires or in the gaz • - Geometry of the detector (electron can cross the source foil because of the magnetic field) • Only right part of the bb(0n) peak is use because of the energy resolution and background from bb(2n) • For SuperNEMO: • Plane geometry  electron will not cross the source foil even with magnetic field • Improvement of energy resolution and T ½ (bb(2n)) longer  larger energy window • Decreasing diameter of wires and cathodic wire in carbon instead of stainless steel higher transparency • Efficiency : ~35 % • Study of the shape of scintillator to try to keep a part of the event with backscattered electrons • All of these number are still preliminary, the goal of the R&D program is to push the limits are far as • possible. • With these preliminary number for 100 kg sensitivity is ~1.2 1026 y Fabrice Piquemal IDEA meeting – Orsay April,2005

  22. 1,5m 1,5m Which laboratory ? Water shield Need of cavity of ~ 60m x 15m x15m Possible in Gran Sasso or in Modane if there is a new cavity From the data obtained with NEMO 3 and with simulations, the muons induced background will be Extrapolate to SuperNEMO Fabrice Piquemal IDEA meeting – Orsay April,2005

  23. R&D for the source of 82Se Goal:To be able to produce 100 kg of 82Se with internal contaminations less than 2 mBq/kg in 208Tl and 10 mBq/kg in 214Bi (60 decays/year) Production:2kg of 82Se funded by ILIAS 100 kg possible in 3 years Development of ICR for enrichment ? Purification:2x100 g natSe already processed at INEEL 2kg of 82Se funded by ILIAS Thickness:~250 m2 with 40 mg/cm2 thickness (6% (FWHM) at 3 MeV) Participants:CENBG, LAL, LSCE (France) ITEP, Kurchatov, JINR (Russia) INEEL, MHC (USA) Fabrice Piquemal IDEA meeting – Orsay April,2005

  24. R&D for Low radioactivity measurements Goal:To develop detectors towards a sensitivity of 2 mBq/kg in 208Tl and 10 mBq/kg in 214Bi To improve HPGe detectors for selection of materials for SuperNEMO To develop detectors sensitive to 0.1 mBq/m3 of radon Ge detectors Today best NEMO HPGe 400 cm3 sensitive to 60 mBq/kg in 208Tl and 200 mBq/kg in 214Bi (1 month, 1 kg) Development with Canberra-Eurysis: larger volume (1000 cm3), background reduced by a factor 10 and higher mass measurement. Need of new set of measurements to select very pure materials for both cryostat and shielding. Planar detector to measure very low energy gamma-rays with 0.5 keV resolution at 40 keV (235U and 238U) Radon detectors Present radon detector sensitive to 1 mBq/m3 (based on Po ions collection in 70 l volume) Development of 1000 l detectors or new methods like drift chambers or using ~20 l liquid scintillator. Participants: CENBG, IReS, LAL (France) Saga (Japan) JINR (Russia) UCL at Boulby (UK) Fabrice Piquemal IDEA meeting – Orsay April,2005

  25. R&D for the calorimeter Goal:To reach 4% (FWHM) at 3 MeV (7% at 1 MeV) with plastic scintillators coupled to PMTs To reduce number of PMT To control quality with test mass production of ~100 units. Plastic scintillators Light yields, homogeneity of response Improvement of Polystyrene in Karkhov and Dubna Development of Polyvinylxylene in Kharkov Studies for use of liquid scintillator Measurements: in France, 2 electron spectrometers Photomultipliers Resolution and low radioactivity In France, agreement with Photonis company In US and UK, tests of Hamamatsu and ETL PMT Simulations and measurements to optimize: thickness, geometry, light collection Electronics development (ASIC, low background voltage divider,…) Participants:CENBG, LAL (France) Kharkov (Ukraine) JINR (Russia) UCL (UK) Prague (Czech Republic) Texas University (USA) Osaka (Japan) Fabrice Piquemal IDEA meeting – Orsay April,2005

  26. Samples from JINR Dubna Results of scintillator measurements done at CENBG for 1 MeV e- Samples are based on the Polystyrene technology. Maximum size of samples: 6x6x2 cm3 Measurements with XP5312B from Photonis company Samples from Kharkov Sample from Bicron Resolution (FWHM) at 1 MeV with XP5312b Scintillator references Fabrice Piquemal IDEA meeting – Orsay April,2005

  27. R&D for drift chamber Goal:To propagate signal along 4 m of wires To improve transparency of tracking volume. To improve transparency by decreasing diameter of wires from 50 mm to 30 mm Use of Carboninstead of Stainless steel for cathode wires Need of prototypes Electronics: low background ASIC Participants: LAL (France) Manchester, UCL (UK) coordinator Fabrice Piquemal IDEA meeting – Orsay April,2005

  28. Other task sharings Calibration survey Goal:To develop a daily calibration check to follow the absolute calibration at a level better than 1% (currently 2% in NEMO 3) Extrapolation of the NEMO 3 system based on laser light:CENBG (France) System based on the use of LED light:CENBG (France), UCL (UK) Electronics and slow control Trigger:LPC-Caen (France) Data acquisition: CENBG, IReS, LPC-Caen (France), Manchester, UCL (UK) Slow control:IReS, LPC-Caen (France), Manchester, UCL (UK) Simulations Goal:To design the detector, to determine precisely the required level of radiopurity and the ultimate sensitivity of SuperNEMO. Both GEANT 3 and GEANT 4 codes will be used for cross-checks. Participants: CENBG, IReS, LAL, LPC-Caen (France), JINR, ITEP (Russia), Manchester, UCL (UK), Fes (Marocco) Mechanics Goal:Design study of the detector Participants:LAL (France), Manchester (UK) Nuclear matrix element theory Goal:To improve the nuclear matrix element calculations to predict the best bb candidate. Calculations based on Shell Model:IReS (France) Calculations based on QRPA:Jyvaskula (Finland), Prague (Czech Republic) Fabrice Piquemal IDEA meeting – Orsay April,2005

  29. This R&D program was presented to the scientific council of IN2P3 in March and accepted with some remarks: to push the R&D to have more ambitious sensitivity and to compare the induce muon background in Modane and Gran Sasso The R&D budget is 600 keuros for the next 3 years In UK, an R&D program was also presented in March, the response will be given in May The collaboration define now more precisely the responsability for the coordination of the task. France will be responsible for the source, low background measurment and calorimeter UK will be responsible of the tracking The mechanics study will be a co-responsability between both France and UK Calendar: R&D 2005-2007 2007 Study of module production 2008 Construction of 1st module 2011 Full detector 2016 results Fabrice Piquemal IDEA meeting – Orsay April,2005

  30. SuperNEMO collaboration steering comittee CENBG, IN2P3-CNRS et Université de Bordeaux, France IReS, IN2P3-CNRS et Université de Strasbourg, France LAL, IN2P3-CNRS et Université Paris-Sud, France LPC, IN2P3-CNRS et Université de Caen, France LSCE, CNRS Gif sur Yvette, France Fes University, Marocco IEAP, CTU Prague, Czech Republic INL, Idaho Falls, USA ITEP, Moscow, Russia JINR, Dubna, Russia KURCHATOV Institute, Russia MHC, MA ,USA Saga University, Japan UCL London, UK University of Manchester, UK University of Texas, USA Osaka, Japan Charles University, Czech Republic ISMA Kharkov, Ukraine + JYVASKYLA University, Finland Comenius University, Slovakia Fabrice Piquemal IDEA meeting – Orsay April,2005

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