1. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 1 The MARE experiment on direct measurement of neutrino mass Daniele Pergolesi UNIVERSITY and INFN of Genova

2. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 2 MARE Microcalorimeter Arrays for a Rhenium Experiment COLLABORATION: INFN sez. Genova and Università di Genova, Dipartimento di Fisica, ITALY NASA Goddard Space Flight Center, USA Universität Heidelberg, Kirchhoff-Institut für Physik, GERMANY Università dell’Insubria, Dipartimento di Fisica e Matematica, ITALY INFN sez. Milano and Università di Milano-Bicocca, Dipartimento di Fisica, ITALY ITC-IRST, Trento, ITALY University of Wisconsin, Physics Department, USA + NIST Boulder USA, Miami University USA, PTB Berlin GERMANY

3. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 3 Scientific motivations : What does the oscillations tell us? - Neutrino has a mass - neutrino is in a coherent superposition of three different states: e    - atmospheric ∆m 23 2 ≈ 2 ⋅ 10 -3 eV 2 ( SK + CHOOZ )  - solar ∆m 12 2 ≈ 7 ⋅ 10 -5 eV 2 (SNO + KAMland) - Approx measurment or constraints on the elements of the mixing matrix: | i  =  U ij | i  What we do not know: - Mass hierarchy: - The absolute mass scale - Neutrino is a Majorana or a Dirac particle? normal inverted Degenerate hierarchy when m 1 ≈ m 2 ≈ m 3

4. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 4 Neutrinoless double beta decay - 0νββ: m e < 0.35 eV (Heidelberg—Moscow 76 Ge) m e < 0.2÷1.1 eV (CUORICINO 130 Te) m e = 0.1÷0.9 eV (Klapdor: : 76 Ge reanalysis) Cosmology: Σm i < 0.42eV (CMB+SDSS+SN) Single  -decay: m e < 2.2eV (Troitsk, Mainz electrostatic spectrometer) All of these techniques are model dependent: 0νββ needs to assume that neutrino is a Majorana particle In an electrostatic spectrometer the  source is outside the detector and the deconvolution from the data of the response function of the spectrometer is complicated (systematic problems with final state corrections, energy loss in the source) Future perspectives for electrostatic spectrometer: KATRIN m e < 0.2eV in 2010. Direct sub-eV determination ( model independent with different systematic ) needed!! Neutrino mass scale determination: Present status

5. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 5 The so-called direct neutrino mass measurement, or its upper limit determination, can be obtained by means of microcalorimeter with internal  source (Re). Only the neutrino energy escapes the detection and the total decay energy minus the energy carried away by the neutrino is measured. What is effectively measured, is the neutrino energy in the form of a missing energy at the end-point of the  -decay spectrum. The lifetime of the excited molecular or atomic states is negligible with respect to the detector time response (i.e. no loss of energy stored in excited states). Good knowledge of the detector response function allows the reconstruction of the theoretical spectral shape. Re is a very efficient absorber for microcalorimeter at the typical working temperature of about 100mK.

6. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 6 MARE Microcalorimeter Array for a Renium Experiment Direct measurement of neutrino mass studying the 187 Re  -decay spectrum MANU MIBETA MANU2 MIBETA2 MARE phase1 MARE phase2

7. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 7 MANU: Results End-point =(2470 ± 1 stat ± 4 sys) eV End-point =(2470 ± 1 stat ± 4 sys) eV Half-life = (4.12 ± 0.02stat ± 0.11sys) 10 10 y Half-life = (4.12 ± 0.02stat ± 0.11sys) 10 10 y m n 2 = - 462 +579 –679 eV 2 /c 4 m n 2 = - 462 +579 –679 eV 2 /c 4 m n < 26 eV/c 2 95% CL, < 19 eV/c 2 90% CL m n < 26 eV/c 2 95% CL, < 19 eV/c 2 90% CL First observation of the Beta First observation of the Beta Environmental Fine Structure (BEFS) microcalorimetric measurement of 187 Re  -decay spectrum Fine structure of the residual

8. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 8 Typical single pixel performance of MIBETA MIBETA: results

9. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 9 Q = 2465.3  0.5 stat  1.6 sys eV  ½ = 43.2  0.2 stat  0.1 sys Gy  M    2 = -112  207 stat  90 sys eV 2  M     15.0 eV (90% c.l.) MIBETA : results

10. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 10 MANU and MIBETA phases II MARE phase I Aims: sensitivity range between 1 and 2 eV MARE phase1 will provide, for the very first time, the opportunity of checking the results obtained with the electrostatic spectrometer

11. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 11 MARE phase1 MIBETA2 Options and perspectives MIBETA2: MC simulation 10 10 events needed to reach the required sensitivity

12. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 12 MANU2 Key Features: 300 microcalorimeters with rhenium 300 microcalorimeters with rhenium single crystal absorber single crystal absorber Required  E: 5-10 eV FWHM @ 6KeV Required  E: 5-10 eV FWHM @ 6KeV TES sensors (Ir/Au –  Al\Ag) TES sensors (Ir/Au –  Al\Ag) operating at about 100mK operating at about 100mK Testing no-SQUID readout electronics Testing no-SQUID readout electronics MANU2 statistical sensitivity MARE phase1

13. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 13 First test of MANU2 single pixel  Ir\Au TES on high purity Si substrate operating at about 80 mK.  Re crystal: (400x470x54)  m 3  Signal amplified (x10) at room T, bandwidth (1-1000)Hz and read out by DC-SQUID Amplitude 2560mV rise time 100  s (10-90 %) Pile-up discrim. time 50  s RMS noise 1.2mV Energy resolution at 6KeV

14. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 14 MARE phase2 From MARE phase1 results: Scaling up to hundreds of channels Optimization of single channel performances Study of the sources of systematic uncertainties Precise understanding of the Re  -decay spectrum (BEFS) Requirements: neutrino mass Stat. Sens. of 0.2eV (90%C.L.) New generation detector: faster rise time (order of  sec),energy resolution of about 5eV FWHM in the energy range of interest) TES-MC MMC ? Read-out electronics: multiplexed SQUID Very big number of channels (order of 5 10 4 ) for M tot ≈ 1Kg, requires detector modularity

15. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 15 MARE phase2 MC simulation of the sensitivity of MARE phase2 (from the Milano Group)

16. Daniele Pergolesi, Institut d’Astrophysique de Paris, Nov 14 th 2005 16 199019952000200520102015 1990 1995 2000 2005 20102015 Spettrometri Calorimetri Sandro Vitale 1985 187 Re 20 eV2 eV0.2 eV 20 eV 2 eV 0.2 eV KATRIN v.s. MARE in sub-eV mass search MANU MIBETA 26 eV 15 eV MARE MAINZ TROITZK spettrometri elettrostatici KATRIN 2.2 eV spettrometri magnetici 20-10 eV From A. Giuliani, Insubria University MARE phase2 will be the only available way to confirm or disprove KATRIN results