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MARE ( microcalorimeter array for a rhenium experiment). Massimiliano Galeazzi for the MARE collaboration. OUTLINE. INTRODUCTION A Rhenium Experiment Cryogenic Microcalorimeters Precursors to MARE (MANU & MIBETA) MARE I (m < 1-2 eV) Status of MARE I in Milan/Wisconsin
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MARE(microcalorimeter array for a rhenium experiment) Massimiliano Galeazzi for the MARE collaboration
OUTLINE • INTRODUCTION • A Rhenium Experiment • Cryogenic Microcalorimeters • Precursors to MARE (MANU & MIBETA) • MARE I (m < 1-2 eV) • Status of MARE I in Milan/Wisconsin • Status of MARE I in Genoa/Miami • MARE II (m < 0.1-0.2 eV) • Requirements • Rhenium vs. Holmium • Technology Development • CONCLUSIONS
OUTLINE • INTRODUCTION • A Rhenium Experiment • Cryogenic Microcalorimeters • Precursors to MARE (MANU & MIBETA) • MARE I (m < 1-2 eV) • Status of MARE I in Milan/Wisconsin • Status of MARE I in Genoa/Miami • MARE II (m < 0.1-0.2 eV) • Requirements • Rhenium vs. Holmium • Technology Development • CONCLUSIONS
A RHENIUM EXPERIMENT Direct measurement of the electron neutrino mass by studying the beta decay of 187Re with cryogenic microcalorimeters. • Radioactive source embedded in the microcalorimeter absorber • Calorimetric Experiment (all the energy, except the neutrino’s, is measured) • All events are detected • Rhenium is the beta isotope with the lowest known endpoint energy (2.47 keV) • Fully complementary to a tritium experiment (different isotope AND different experimental technique) • Expected sensitivity of MARE ~ 0.1-0.2 eV/c2
CRYOGENIC MICROCALORIMETERS FALL TIME (Depends on C, G, Bias Power) RISE TIME (Depends on Absorber)
RESISTIVE SENSORS • Thermistors • Very high resistance • Negative “low” sensitivity • FET readout • TES • Very low Resistance • Positive “high” sensitivity • SQUID readout
NON-RESISTIVE SENSORS A. Fleischmann et al., LTD13
MANU & MIBETA MANU: Re single crystal with NTD Ge thermistors MIBETA: AgReO4 with Si implanted therimostors END POINT 2465.3±0.5(stat)±1.6(syst) eV 2470±1(stat)±4(syst) eV HALF LIFE 4.32±0.02(stat)±0.01(syst) 1010 yrs 4.12±0.02(stat) ±0.11(syst)1010 yrs MASS mn < 15 ev/c2 mn < 26 ev/c2 BETA ENVIRONMENTAL FINE STRUCTURE (BEFS) HEAVY NEUTRINOS
OUTLINE • INTRODUCTION • A Rhenium Experiment • Cryogenic Microcalorimeters • Precursors to MARE (MANU & MIBETA) • MARE I (m < 1-2 eV) • Status of MARE I in Milan/Wisconsin • Status of MARE I in Genoa/Miami • MARE II (m < 0.1-0.2 eV) • Requirements • Rhenium vs. Holmium • Technology Development • CONCLUSIONS
MARE I • m < 2 eV/c2 • 1010 events - 300 sensors Milano / Como / IRST / Wisconsin / NASA/GSFC • 8 arrays of Si:P thermistors with AgReO4 absorbers • energy resolution 25 eV @ 2.6 keV • Genoa / Miami / Florida / Lisbon • Ir TES with Re crystal absorbers • Energy resolution <10 eV
MARE I - MILAN 600 µm 300 mm Si support • Single crystal of silver perrhenate (AgReO4) as absorber • mass ~ 500 mg per pixel (Ab~ 0.3 decay/sec) • regular shape (600x600x250 mm3) • low heat capacity due to Debye law • 6x6 array of Si thermistors (NASA/GSFC) • pixel: 300x300x1.5 mm3 • high energy resolution • developed for X-ray spectroscopy
MARE I - MILAN Top=85 mK Mn Ka Al Ka Ca Ka Ti Ka Mn Kb Cl Ka Ca Kb Ti Kb calibration spectrum • DE = 33 eV@ 2.6 keV • tR ~ 500 ms • Araldit / ST2850
MARE I - MILAN • FIRST 11 CRYSTALS • Thermal coupling: • ST2850 spacer/absorber • Araldit or ST1266 thermistor/spacer
MARE I - MILAN • SUMMARY • The first phase of MARE-1 in Milan is getting ready to start at the end of September with 72 channels • With 72 channels a sensitivity on neutrino mass of about 5 eV can be achieved in two years • Based on these preliminary results, a decision concerning funding of the deployment of the remaining 6 arrays can be made
MARE I - GENOA • Single crystal of pure Re as absorber • Ir TES on Si3N4 membrane • Gold thermal link between absorber and TES • Energy Resolution ~10 eV FWHM Re TES O TES Metal contact
MARE I - GENOA Ir TES on Si3N4 membrane Re crystal on top of TES Re crystal Al leads for TES
MARE I - GENOA • SUMMARY • The first phase of MARE-1 in Genoa is starting in September • Single SQUID readout for the initial detectors • SQUID multiplexing available by the end of the year • Expected sensitivity of ~0.2 eV in 2 years of data taking
OUTLINE • INTRODUCTION • A Rhenium Experiment • Cryogenic Microcalorimeters • Precursors to MARE (MANU & MIBETA) • MARE I (m < 1-2 eV) • Status of MARE I in Milan/Wisconsin • Status of MARE I in Genoa/Miami • MARE II (m < 0.1-0.2 eV) • Requirements • Rhenium vs. Holmium • Technology Development • CONCLUSIONS
MARE REQUIREMENTS EXPERIMENTAL CONSTRAINS • Statistics • Unresolved pileup • Energy Resolution • Energy calibration • Background • BEFS
MARE REQUIREMENTS REQUIRED EXPERIMENTAL PARAMETERS
MARE REQUIREMENTS Sources of Uncertainty
CURRENT STATUS OF MARE The full MARE experiment is still in the R&D phase and multiple options are being evaluated. In particular: ISOTOPE TECHNOLOGY 187Re 163Ho TES MagCal
RHENIUM VS. HOLMIUM • finite neutrino mass causes a kink at the end-point similarly to beta spectra
RHENIUM VS. HOLMIUM • Advantages of a Ho experiment: • tunable source activity independent on the absorber mass • Minimization of the absorber mass to the minimum required by the full absorption of the energy cascade resolution less dependent on the activity • Rise-time less of 10 us for SiN suspended detector • Higher Counting rate per detector • Self calibrating experiment • Easiest way to reach higher count rate with presently better performing detectors
RHENIUM VS. HOLMIUM The necessary statistics for a Ho experiment depends on the exact value of the IB endpoint energy, but should be comparable to that of a Re experiment
RHENIUM VS. HOLMIUM • In the past the Genoa group made a tentative experiment to verify the feasibility of a measurements • Ho-163 Cl solution from ISOLDE (E Laesgaard) after a tentative made by INR-Moscow (purification failed) • Final result was an admixture of fine salt grain onto a Sn matrix • The final energy resolution was not satisfactory NTD thermistor Salt grains in Sn matrix (absorber)
RHENIUM VS. HOLMIUM • 100 eV at 2 keV • 40 eV at 6 keV cal line • Broad, non-Gaussian MI line • 8% disagreement on energy line measured with respect to the expected. • However 4 lines resolved: MI,MII,NI,NII and a preliminary analysis gives Q=2.80+/-0.05 keV. • More recently implantation tests have been done at ISOLDE (CERN), but first sample contains high level of radioactive impurities
MARE The full MARE experiment is still in the R&D phase and multiple options are being evaluated. In particular: ISOTOPE TECHNOLOGY 187Re 163Ho TES MagCal
TES PERFORMANCE TES development at NASA/GSFC
MAGNETIC CALORIMETER DEVELOPMENT A. Fleischmann et al., LTD13
MAGNETIC CALORIMETER DEVELOPMENT A. Fleischmann et al., LTD13
CURRENT WORK ON MARE • Re-Ir TES detectors (Genoa, Miami) • AgReO –Si array (Milan-Wisconsin-Goddard) • MUX Readout (PTB-Genoa) • Kinetic Inductance Sensor (Como-IRST-Trento) • Magnetic Calorimeter (Heidelberg) • Semi-analytical modeling for experimental design (Milan) • GEANT simulation and data Analysis ( U.Florida-Miami) • Ho-163 (Genoa-Goddard-Miami-Lisbon, Heidelberg) • TES physics (Lisbon-Miami) • Production and study of E.C. isotopes (GSI)
DETECTOR READOUT 10,000-50,000 Channels SINGLE CHANNEL READOUT (wiring, power consumption) SQUID MULTIPLEXING Time division Multiplexing Frequency division multiplexing Microwave Multiplexing SQUID MULTIPLEXING Time division Multiplexing Frequency division multiplexing Microwave Multiplexing
READOUT MULTIPLEXING Genoa-PTB development of frequency MUX readout PTB SQUID under test at Genoa
READOUT MULTIPLEXING NIST development on MUX readout Time Domain Multiplexing Microwave Multiplexing
UNIFORMITY OF IRIDIUM THIN FILMS 4” • 3 • 4 6 • 12 17 14 4 3 2 9 10
FULL SCALE REALISTIC SIMULATION THE SIMULATION Geant Monte Carlo to simulate the individual Re decays and create an event list containing relevant event parameters such as energy, time, and position (within the microcalorimeter). Numerical solver to model the non-linear response and noise of the microcalorimeter. Optimal filter analysis of the simulated pulses to generate a "data-like" beta spectrum. • GOALS OF THE SIMULATION • Understanding the systematics of the experiment • Optimization of the experimental design (size of the absorbers, number of detectors, detectors parameters, etc.) • Improve the analysis procedure (by incorporating, for example, the unidentified pileup spectrum in the fitting procedure)
SIMULATION TEST RUN • Unidentified pileup • Effect of the decay position in the absorber • Efficiency and systematics of the analysis tools • Background events originating from radioactive decays in the surrounding cryostat material 8x108 events 1 mg detector
THE BIG CHALLENGES ABSORBER PHYSICS FABRICATION ISOTOPE GENERATION ISOTOPE IMPLANT RHENIUM HOLMIUM
CONCLUSION • 1) MARE I development is finished and should start taking data in September (1-2 yrs of data taking) • 2) MARE II is a challenging experiment, but feasible. • Technology ready and mature. • In the next 2-3 years a decision on the isotope and detector technology should be made and a prototype detector built. • Full development could start immediately after that (if funding is available both in the US and Europe) • 3) MARE will provide fully complementary results to KATRIN