CEA Irfu – Service de Physique Nucléaire Searching for sterile neutrinos with reactor experiments Jonathan Gaffiot, Ph.D. CEA Saclay: IRFU – Service de Physique Nucléaire Nucifer project - STEREO project 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 1

CEA Irfu – Service de Physique Nucléaire REACTOR ANTINEUTRINO ANOMALY 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 2

CEA Irfu – Service de Physique Nucléaire Neutrino spectra 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 3 Uranium 235

CEA Irfu – Service de Physique Nucléaire Reactor Antineutrino Anomaly 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 4

CEA Irfu – Service de Physique Nucléaire 4 th neutrino hypothesis Disparition of neutrinos: new oscillation ? 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 5 G. Mention et al., Phys. Rev. D 83, (2011) Atmospheric oscillation Solar oscillation New oscillation to sterile ?

CEA Irfu – Service de Physique Nucléaire Reactor norm only Reactor norm + shape (Bugey3 15m/40m) Reactor norm + reactor shape + gallium Anomaly contours 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 6

CEA Irfu – Service de Physique Nucléaire Detector specifications and challenges 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 7

CEA Irfu – Service de Physique Nucléaire ON GOING PROJECTS Nucifer DANSS 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 8

CEA Irfu – Service de Physique Nucléaire Nucifer experiment 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 9 70 MW Contact: T. Lasserre, D. Lhuillier, M. Fallot 7 m

CEA Irfu – Service de Physique Nucléaire Commissioning and data taking Data taking since april 2012 –Agreement from French National Security Agency (ASN) Remote control & automatic data transfert Accurate monitoring (Rates, gains, P, T…) Detector works well ! 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's Co AmBe Reactor shutdown

CEA Irfu – Service de Physique Nucléaire Accidental background New south lead wall –Lead already acquired –Installation at end of /15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 11 Barycenters of the PMT’s charges East South 3 m 2 m pool concrete core 3.35 m 4 m 1.2 m Reactor OFF background on expectation primary loop water deactivation circuit Primary loop water activation –High energy  leakage from 16 N

CEA Irfu – Service de Physique Nucléaire Liquid scintillator upgrade 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 12

CEA Irfu – Service de Physique Nucléaire Contour after upgrades 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 13 Expected spectrum distortion - Error stat only Osiris Upgrades planned to be finished early 2013 With upgrades: MC detector response Ref spectra uncertainty

CEA Irfu – Service de Physique Nucléaire DANSS experiment 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 14 Contact: V. Egorov

CEA Irfu – Service de Physique Nucléaire NEW DEDICATED PROJECTS SCRAAM STEREO NEUTRINO-4 POSEIDON 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 15

CEA Irfu – Service de Physique Nucléaire SCRAAM project 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 16 Contact: N. Bowden Spectral (24m),  1MeV sin 2 (2  ) =0.165,  m 2 =2.4 eV 2

CEA Irfu – Service de Physique Nucléaire STEREO project French and German project ILL research reactor (Grenoble): –57 MW, highly enriched U –Compact: h = 80 cm, Φ = 40 cm Dedicated detector: –5 segments: L and E oscillation –Active outer layer: high efficiency + veto –Muon flux attenuation = 4, thick CH 2 and Pb walls (70 t) 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's cm 36 cm Target: Gd-doped liquid scintillator 5 m Contact: D. Lhuillier Site being discussed with ILL

CEA Irfu – Service de Physique Nucléaire A phase shift of the oscillation is expected, no input from reactor. Unambiguous signature of neutrino oscillation STEREO contour and phase shift 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 18 Best fit, shape + norm, 300 days MC detector response Ref spectra uncertainty

CEA Irfu – Service de Physique Nucléaire NEUTRINO-4 experiment SM-3 reactor in Dimitrovgrad (Russia): –100 MW compact core (35x42x42 cm 3 ) 2 detector geometries currently studied: –24 sections 1.4x1.0x1.0 m 3 –5 sections moveable at 6-12 m Preparation at WWR-M reactor in Gatchina Future realization at SM-3 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 19 detector core 5 m WWR-M reactor, 18 MW Shielding studies SM-3 reactor 24 sections 5 sections at SM-3, 95% C.L. Contact: A. Serebrov

CEA Irfu – Service de Physique Nucléaire POSEIDON – POsition SEnsItive Detector Of Neutrino 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 20 Gd loaded liquid scintillator detector: 2.1x1.3x1.3 m 3 Region of sensitivity: δm 2 = ( ) eV 2 sin 2 (2  )≥ 0.01 LAB+PPO+Gd 15 cm Veto+anti ” PMTs Energy and spatial resolution should allow to observe the oscillation curves for different E ν Contact: A. Derbin

CEA Irfu – Service de Physique Nucléaire Conclusions 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 21

CEA Irfu – Service de Physique Nucléaire Back-up 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Shape only data 09/15/ Bugey3 comparison 40m/15m: ILL pattern (not statistically significant) Bugey (1995) ILL (1981 – reanalysis 1995) - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Nucifer Intallation 09/15/ Lead shielding CH2 shielding Muon veto Lead front wall Shielding support Filling - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Photoelectron calibration LED + fiber + diffuser  single photoelectron signal Automatic fit of spe (16 ch)  pedestal + gain Others LED for stability, linearity 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 25 Pedestal % Gain % Measured each run or 10 runs (need statistic)

CEA Irfu – Service de Physique Nucléaire Sources simulation 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's 26

CEA Irfu – Service de Physique Nucléaire Pulse Shape Discrimination in Nucifer 09/15/ PXE 50% - Dodecane 50% - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Reactor Spectrum Calculation  Sensitivity to plutonium content 09/15/  235U  239Pu - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Neutrinos & non proliferation Arrêt réacteur rechargement d’1/3 du combustible  1m 3 detector 25 m away from a 3 GW reactor  2000 interactions/d A neutrino working group was created last year by the AIEA Reactor operating at constant power P (GW) At fixed power the rate decreases as Pu accumulates in the core 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Passive Shielding 30 Lead Iron * Cosmic Ray Interactions in Shielding Materials, E. Aguayo et al, PNNL Study of cosmic rays attenuation at surface performed for the MAJORANA collaboration *  Favor thick light materials. Concrete 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire STEREO shape only contours 09/15/ Background shape uncertainty - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire DANSS contour from Saclay team Core size prevents effective oscillation detection 09/15/ Shape only analysis - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Mean cross-section per fission 09/15/   -flux: 235 U +3.7%, 239 Pu +4.2%, 241 Pu +4.7%, 238 U +9.8% (σ f pred  )  Neutron lifetime decrease by a few % (σ f pred  )  Off-equilibrium corrections (σ f pred  ) +4.7% +5.0% +9.7% +5.2% new/old Updated cross-sections per fission: - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire spectrum emitted by a reactor 09/15/ =  all fission products - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Accurate prediction of reactor spectra Thermal power δP th ~ 0.5% at commercial reactors Fraction of fissions from isotope k, δ  k =few % E released per fissions of isotope k, δE k ≈0.3% ν spectrum per fission Dominant source of uncertainty Reactor data Nuclear databases Reactor evolution codes 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Reactor Spectrum Calculation 09/15/ Detected spectrum / fission Cross section / fission: - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire The guts of S k (E) Sum of all fission products’ activities Sum of all β-branches of each fission product Theory of β- decay 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Theory of  -decay 09/15/ W = total energy W 0 = end-point p = momentum Z = Nuclear charge Fermi theory: Corrections: Fermi function Phase space Shape factor of forbidden Finite size of nuclear electric charge Finite size distrib. of decaying neutron Screening of Atomic e- QED radiative correction Weak magnetism branch obtained by replacing: W  W 0 -W, G   G - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Corrections to Fermi theory 09/15/ Example of a single branch with Z=46 A=117 E 0 =10 MeV Total fission spectra is a sum over a quasi continuous end-point distribution  +/- cancellation at low E, adds up at high E. Can’t neglect this when looking for oscillation patterns or accurate total rate. P. Huber  spectrum corrections spectrum corrections - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Neutron Life time 09/15/ Continuous decrease of  n in the history of measurements Latest average including MAMBO II result:  n = s - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire ILL data: reference  - Spectra 09/15/ Target foil ( 235 U, 239 Pu, 241 Pu) in thermal n flux Magnetic BILL spectrometer ILL research reactor (Grenoble, France) e-e- Emitted  spectra per fission  A. A. Hahn, K. Schreckenbach et al., Phys. Let. B218,365 (1989)+ refs therein Accurate e - ILL in Grenoble ( )  W. Mampe et al., Nucl. Instrum. Meth. 154 (1978). - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Normalization of ILL data 09/15/ Pb(n,  ) 208 Pb 115 In(n,  ) 116m In 113 Cd(n,  ) 114 Cd Dominant systematic error : 1.8 % (1  ) Absolute calibration via internal conversion electron lines of known partial cross section per neutron capture Correlated across all energy bins of all isotopes + directly propagates into the converted antineutrino spectra. &: absolute normalization : relative normalization - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire e -   conversion 09/15/  -branch level Fission product  level Lot of relevant quantities: Z, A, End-points, J , nuclear matrix elements, branching ratios, fission yields, life time… but scarce data as E  increases Exact conversion requires complete knowledge from fission yield down to  - transition between parent ground (or isomeric)-state and daughter states - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Conversion of reference e - spectra Fit total e - spectrum with a sum of 30 effective  branches determined by iterative method (instead of ~10,000+ real branches) 2- Convert each effective e - branches to ν branches 3- Sum all converted ν branches to get total ν spectrum K. Schreckenbach et al., Phys. Lett. 99B, 251 (1981). A.A. Hahn et al., Phys. Lett. 218B, 365 (1989). - Jonathan Gaffiot - Reactor experiments to test sterile nu's 09/15/2012

CEA Irfu – Service de Physique Nucléaire ILL spectra 09/15/ Emitted spectrum / fission Converted energy spectrum S(E) for 235 U, 239 Pu and 241 Pu. Reference spectra over the last 25 years Ab initio calculation for 238 U spectrum + new data from FRM2 (Nils Haag et al.) - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire New Predictions of Spectra 09/15/ Residuals to reference ILL data  +3% normalization shift with respect to ILL ν spectrum  Similar result for 235 U and Pu isotopes, +9.8% for 238 U because of more complete ab initio approach.  Origin of the bias well identified: - Effective implementation of corrections to Fermi theory - Nuclear charge distribution of virtual branches Th. Mueller et al, Phys. Rev. C83, (2011) - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Confirmed by Independent Work 09/15/  Confirms global increase of predicted spectrum  Fixes remaining oscillations of mixed-approach prediction  Extra deviation at high energy from more complete correction to Fermi theory.   -flux: 235 U +3.7%, 239 Pu +4.2%, 241 Pu +4.7% New conv. New conv. with simple  -shape Mixed-approach ILL inversion P. Huber, Phys. Rev. C84, (2011) - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Reanalysis of All Short Baseline experiments 09/15/ Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire 19 L<100m 09/15/ Bugey Savannah River Rovno Goesgen ILL Krasnoyarsk Different detector technics, different core compositions, different backgrounds, … - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire 19 L<100m 09/15/ Variety of detection techniques, baselines, core compositions,… meas/pred - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire Correlation Matrix 09/15/  Bugey-4 15m  Rovno91 18m  Bugey-3 15m  Bugey-3 40m  Bugey-3 92m  Goesgen 38m  Goesgen 45m  Goesgen 65m  ILL 9m  Krasno 33m  Krasno 92m  Krasno 57m  SRP I 18m  SRP II 25m  Rovno88 1I 18m  Rovno88 2I 18 m  Rovno88 1S 18m  Rovno88 2S 25m  Rovno88 3S 18m  Global 2% correlated norm error of ILL β-spectra  Block correlations come from identical detector, technology or source (in %) (correlation matrix on Ratios) - Jonathan Gaffiot - Reactor experiments to test sterile nu's

CEA Irfu – Service de Physique Nucléaire 238 U  spectrum soon to be published 09/15/  N. Haag Ph.D. thesis to be published by end of this year.  Analysis of electron data is final, conversion to neutrino on progress. Anchor point of 235U measurement: - Background well understood. - Comparison to ILL spectrum cancels most uncertainties. N. Haag, K. Schrekenbach et al. New 238 U FRMII reactor, Munich n flux Natural U foil  MWC Plastic Scintillator - Jonathan Gaffiot - Reactor experiments to test sterile nu's