1. Slides for IG NewS : GG – analysis june 2012

2. 22 juin 2016 Spherical detector: recent developments I. Giomataris, CEA-Irfu-France Spherical detector at LSM laboratory Spherical detector at Saclay

3. 22/06/2016I. Giomataris Radial TPC with spherical proportional counter read-out Saclay-Thessaloniki-Saragoza, Ioannina 5.9 keV 55 Fe signal E=A/R 2 20  s Simple and cheap single read-out Robustness Good energy resolution Low energy threshold Efficient fiducial cut 15 mm ‘A Novel large-volume Spherical Detector with Proportional Amplification read-out’, I. Giomataris et al., JINST 3:P09007,2008 C= R in = 7.5 mm < 1pF

4. 22/06/2016I. Giomataris Micromegas GEM E= constant C ≈ S > 1nF Parallel Plate Detector E=1/r 2 C ≈ R in < 1pF Spherical Proportional Counter E=1/r C ≈ L>10 pF MPWC

5. 22/06/2016I. Giomataris Good energy resolution- neutron capture 222 Rn 218 Po 214 Po Energy resolution under amplification: a world record !! RMS =.5% Neutron energy and flux measurement 3 He + n 1 H + 3 H (Q= 760 keV) In 2008: Detector installed in LSM laboratory Goal: measure thermal neutron background and estimate fast neutron flux Visit on December 2008 Thermal neutrons, 760 keV Results in LSM Thermal neutron flux 2.2x10 -6 /cm 2 /s

6. I. Giomataris + N --> +N  ≈ N 2 E 2, D. Z. Freedman, Phys. Rev.D,9(1389)1974 Neutrino-nucleus coherent elastic scattering High cross section but very-low nuclear recoil Illustration: using the present prototype at 10 m from the reactor, after 1 day run A. Druikier, L. Stodolsky, Phys.Rev.D30:2295,1984, JI Collar, Y Giomataris - NIMA471:254-259,2000, H. T. Wong, arXiv:0803.0033-2008, PS Barbeau, JI Collar, O Tench - Arxiv preprint nucl-ex/0701012, 2007 T N =2 m N (E n cos  ) 2 /{(m N + E n ) 2 − (E n cos  ) 2 } target anti  e (QF, no Thr) anti e (QF ) Thr = 1 electron anti e (QF ) Thr = 2 electron Xe2325825275 Ar430292210 Argon is a good candidate Challenge : Very low energy threshold We need to calculate and measure the quenching factor Application : Remote control of nuclear reactor

7. Simulated experimental spectrum from reactor neutrinos (pure 235 U : TL) 300 ev/keV.kg.d 1200 ev/keV.kg.d eVee Two measurements of 30 days with reactor on/off gives 10 sigma in (50-150) eV If back rate is reduced by 100 wrt surface 2.8 GW reactor at 20 m distance in 0.6 m diameter sphere with Ar @ 5 bar (1kg) Quench factor included (Ge) Ionisation : 30 eV/electron 30 days exposure (30 kg.d) => 3400 evts

8. I. Giomataris Ultra low energy threshold observed arXiv:1010.4132 [physics.ins-det], 2010

9. 22/06/2016 Last success: home made Ar-37 source Using Ca-40 powder About 40 hz after 14 days Of neutron irradiation: 7x10 6 neutrons/s 250 mbar gas 8 mm ball Fe-55 5,9 keV 3 keV 260 eV

10. 22/06/2016I. Giomataris Attenuating UV light down to single electrons Sub-keV calibration: UV lamp We are using a pulsed hydrogen lamp MgF 2 entrance window Electrons are extracted by the internal spherical vessel UV attenuators: 38% transparent mesh

11. Sensitivity for galactic explosion For p=10 Atm, R=2m, D=10 kpc, U ν =0.5x10 53 ergs # Number of events ( no quenching, zero threshold ) He Ne Ar Kr Xe Xe ( with Nuc. F.F ).16 3.95 19.1 76.8 235 179 # Number of events ( after quenching, E th =0.25 keV ) He Ne Ar Kr Xe Xe ( with Nuc. F.F ) 0.08 1.5 6.7 23.8 68.1 51.8 Idea : A world wide network of several (tenths or hundreds) of such dedicated Supernova detectors robust, low cost, simple (one channel) To be managed by an international scientific consortium and operated by students Destruction of massive star initiated by the Fe core collapse 10 53 ergs of energy released 99% carried by neutrinos A few happen every century in our Galaxy, but the last one observed was over 300 years ago A dedicated Supernova detector Simple and cost effective - Life time >> 1 century Through neutrino-nucleus coherent elastic scattering Y. Giomataris, J. D. Vergados, Phys.Lett.B634:23-29,2006

12. 22/06/2016I. Giomataris Dark matter search through very low energy threshold < 100 eV CoGeNT 2010

13. 22/06/2016I. Giomataris22/06/2016I. Giomataris 22/06/2016I. Giomataris Under preparation SEDINE project New detector made out of radiopure Cu vessel Diameter = 60 cm Pressure = up to 10 bar Appropriate shield will be provided by LSM Goal Measure fast neutron energy distribution at LSM Explore ultra low energy with low background detector

14. 22/06/2016I. Giomataris