SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
Outlook
The SOX experiment
Jonathan Gaffioton behalf of the SOX collaboration
CNRS / APC
September 12, 2014
Jonathan Gaffiot: CNRS / APC The SOX experiment 1 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
Outlook
Outlook
1 SOX: Short (distance neutrino) Oscillations with BoreXinoThe scientific caseThe Borexino detectorThe SOX experiment
2 The cerium experiment: CeSOXProductionShielding and transportSignal and backgrounds
3 The chromium experiment: CrSOXProductionShielding and transportSignal and backgrounds
4 Perspectives and conclusionsCompared sensitivitySource activity measurementSchedule and perspectivesConclusions
Jonathan Gaffiot: CNRS / APC The SOX experiment 1 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
The scientific caseThe Borexino detectorThe SOX experiment
Outlook
1 SOX: Short (distance neutrino) Oscillations with BoreXinoThe scientific caseThe Borexino detectorThe SOX experiment
2 The cerium experiment: CeSOXProductionShielding and transportSignal and backgrounds
3 The chromium experiment: CrSOXProductionShielding and transportSignal and backgrounds
4 Perspectives and conclusionsCompared sensitivitySource activity measurementSchedule and perspectivesConclusions
Jonathan Gaffiot: CNRS / APC The SOX experiment 1 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
The scientific caseThe Borexino detectorThe SOX experiment
The scientific case
3 anomalies at the ∼ 3σ level eachLNSD [1] and MiniBooNE [2, 3]Calibration of radiochemical solar experiments [7, 8, 6]Short baseline reactor experiments [9, 10, 11, 13]
The 3 anomalies point toward a new oscillation with |∆m2new| ∼ 0.1− 5 eV2
See talks of Patrick Huber, Michele Maltoni and Thierry LasserreN
OB
S/(
NE
XP) p
red
,new
Distance to Reactor (m)
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101
102
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0.7
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1.1
SOX goal: unambiguously test the short baseline oscillation hypothesis
Jonathan Gaffiot: CNRS / APC The SOX experiment 2 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
The scientific caseThe Borexino detectorThe SOX experiment
The Laboratori Nazionali del Gran Sasso (LNGS)
ref [12]
Deep underground laboratory: 1400m ⇒ 3800m.w.e. and 1.2muons h−1 m−2
Jonathan Gaffiot: CNRS / APC The SOX experiment 3 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
The scientific caseThe Borexino detectorThe SOX experiment
The Borexino detector
Water volumeMuon veto and
radioactivity shielding2.1 kt, r=9 m, 208 PMT
Buffer volumeRadioactivity shielding
800 t, r=6.85m, 2212 PMT
Active volumeLiquid scintillator (PC+PPO)
300 t, r=4.25m
Stainless steel tanks
Nylon vessels
Stainless steel plates10 cm + 4 cm
1.05 m
8.5 m
ref [12]
Jonathan Gaffiot: CNRS / APC The SOX experiment 4 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
The scientific caseThe Borexino detectorThe SOX experiment
The Short (distance neutrino) Oscillations with BoreXino experiment
SOX: Deploy a neutrino and an antineutrino source under Borexino
ref [15]ref [4]
Jonathan Gaffiot: CNRS / APC The SOX experiment 5 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
The scientific caseThe Borexino detectorThe SOX experiment
Neutrino and antineutrino sources
Neutrino source:51Cr
Electron capture:753 keV (90%) and433 keV (10%) νe
Half-life: 27.7 dayProduced byneutron irradiationof (stable) 50CrScattering on e−
Backgrounds:210Po, 210Bi, and7Be solar νe
Activity: ∼ 10MCi⇒ 2 kW
144Ce
144Pr
144Nd
696 keV
17 mn
285 d
ß- < 318 keV
ß- < 2996 keV
97.9 %
ß- < 913 keV 1 %
ß- < 2301 keV 1 %
γ 2185 keV
0.7 %
Antineutrino source:144Ce-144Pr
β− decay: ν̄e up to3.00MeV144Ce half-life: 285 dExtracted from nuclearspent fuelInverse beta decay
Threshold 1.8MeVCross-section ∼ 10times higher than νeCoincidence betweene+ and neutron
∼ background freeActivity: ∼ 100 kCi⇒ 0.8 kW
Main issue: produce and bring the sources to LNGS
Jonathan Gaffiot: CNRS / APC The SOX experiment 6 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
ProductionShielding and transportSignal and backgrounds
Outlook
1 SOX: Short (distance neutrino) Oscillations with BoreXinoThe scientific caseThe Borexino detectorThe SOX experiment
2 The cerium experiment: CeSOXProductionShielding and transportSignal and backgrounds
3 The chromium experiment: CrSOXProductionShielding and transportSignal and backgrounds
4 Perspectives and conclusionsCompared sensitivitySource activity measurementSchedule and perspectivesConclusions
Jonathan Gaffiot: CNRS / APC The SOX experiment 6 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
ProductionShielding and transportSignal and backgrounds
Production
One company can produce such a source: the Russian FSUE Mayak PA.
1 Start with 2.8 t of fresh spent fuel (1.65 year of cooling time) from Kola NPP2 Cutting, digestion and PUREXr process⇒ lanthanides and actinides concentrate3 Displacement chromatography ⇒ extraction of all cerium isotopes ∼ 5 kg4 Precipitation, calcination in CeO2, pressing, encapsulation and insertion in shield
Jonathan Gaffiot: CNRS / APC The SOX experiment 7 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
ProductionShielding and transportSignal and backgrounds
Shielding and transport2.185MeV γ ray with intensity 0.7%
19 cm tungsten alloy shielding (2.4 t)density 18 g/cm3, leading to 5× 10−7 attenuation
Selected cask: MTR from Areva TN (21 t)Certification extension ongoingFrom Mayak to LNGS through France:train, boat, truck ; supervised by Areva TN
Jonathan Gaffiot: CNRS / APC The SOX experiment 8 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
ProductionShielding and transportSignal and backgrounds
Signal and backgrounds
Eν (MeV)
Arb
itra
ry U
nit
144Ce−
144Pr antineutrino emitted spectrum in secular equilibrium
0 0.5 1 1.5 2 2.5 310
−2
10−1
100
Cou
nts
per
0.10
mM
eV−1
bin
2 3 4 5 6 7 80
50
100
150
200
250
300
350
400
450
500
No oscillationssin2(2θ
new) = 0.10, Δm2
new= 0.5 eV2
sin2(2θnew
) = 0.10, Δm2new
= 2 eV2
R/E (m MeV−1)
Osc
/No
osc
ratio
2 3 4 5 6 7 80.85
0.9
0.95
1
∆m2new = 2.5 eV2 and sin2(2θ) = 0.16
Pattern in L and in E : shape-only signature+ disappearance measurementHuge overburden and perfect material purity⇒ no backgrounds except geoneutrinos andreactor neutrinos!Simulations show no source inducedbackground
Jonathan Gaffiot: CNRS / APC The SOX experiment 9 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
ProductionShielding and transportSignal and backgrounds
Outlook
1 SOX: Short (distance neutrino) Oscillations with BoreXinoThe scientific caseThe Borexino detectorThe SOX experiment
2 The cerium experiment: CeSOXProductionShielding and transportSignal and backgrounds
3 The chromium experiment: CrSOXProductionShielding and transportSignal and backgrounds
4 Perspectives and conclusionsCompared sensitivitySource activity measurementSchedule and perspectivesConclusions
Jonathan Gaffiot: CNRS / APC The SOX experiment 9 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
ProductionShielding and transportSignal and backgrounds
Production
ref [14]Re-use of Gallex Cr,36 kg enriched in50Cr at 38%
Irradiation plannedat Oak Ridge HFIRSimulations ongoingto optimize activity:currently with 2back-to-back cycles,5–6MCi are reached
Jonathan Gaffiot: CNRS / APC The SOX experiment 10 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
ProductionShielding and transportSignal and backgrounds
Shielding and transport
Due to the short period of 51Cr, the whole procedure below must not last morethan 1 week
1 After irradiation, chromium is dispatched in hot cell between 3 capsules2 Each capsule is inserted in separated transport casks specially built by Croft (UK)3 Containers are transported by plane to Italy, then by truck to Nucleco in Casaccia4 Cr is gathered in 1 source in hot cell then inserted in a tungsten alloy shield5 The source is transported to LNGS and mounted within the calorimeter6 The whole system is inserted in the pit for 3 months7 Repeat steps 1 to 6 to reach a total of 10MCi
ref [14]
Jonathan Gaffiot: CNRS / APC The SOX experiment 11 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
ProductionShielding and transportSignal and backgrounds
Signal and backgrounds
electron recoil energy [MeV]0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
#[per
133tx
1da
yx0.1MeV
]
-110
1
10
210
310
51Cr
11C
pep-ν
7Be-ν
210Po
ref [15]
2241
142
eV2Δm0.32θsin
==
ref [5]
Below 753 keV, 2 main backgrounds:Solar neutrinos (from 7Be)210Po which peaks around 450 keV
Both are well known!Pattern measurable in L: shape-only signature+ disappearance measurement
Jonathan Gaffiot: CNRS / APC The SOX experiment 12 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
Compared sensitivitySource activity measurementSchedule and perspectivesConclusions
Outlook
1 SOX: Short (distance neutrino) Oscillations with BoreXinoThe scientific caseThe Borexino detectorThe SOX experiment
2 The cerium experiment: CeSOXProductionShielding and transportSignal and backgrounds
3 The chromium experiment: CrSOXProductionShielding and transportSignal and backgrounds
4 Perspectives and conclusionsCompared sensitivitySource activity measurementSchedule and perspectivesConclusions
Jonathan Gaffiot: CNRS / APC The SOX experiment 12 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
Compared sensitivitySource activity measurementSchedule and perspectivesConclusions
--- RA (95% C.L.)
--- RA (99% C.L.)
--- SOX Cr (95% C.L.)
--- SOX Cr (99% C.L.)
--- SOX Ce (95% C.L.)
--- SOX Ce (99% C.L.)
Global fit. Giunti et al.Physical Review D, vol.88, 073008, 2013
ref [5]
Sensitivity is dominated by statistic and activity uncertainty (particularly at high∆m2
new)
Jonathan Gaffiot: CNRS / APC The SOX experiment 13 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
Compared sensitivitySource activity measurementSchedule and perspectivesConclusions
Source activity measurement
Main source activity measurement: calorimetryCross-check with other methods based on sampling are foreseen
Goal: the percent level (at least 1.5%)
(multi layer insulation not represented)
Cerium calorimeter1 day measurement before deployment
Chromium calorimeterContinuous measurement during the
experiment
Jonathan Gaffiot: CNRS / APC The SOX experiment 14 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
Compared sensitivitySource activity measurementSchedule and perspectivesConclusions
Schedule and perspectives
ScheduleFebruary 2015: arrival of fresh nuclear fuel at MayakNovember 2015: delivery of the cerium source by MayakDecember 2015: start of 1.5 year of data-taking with 144Ce2016+: chromium irradiation at HFIRLater: deployment of new sources inside Borexino!
In the water volume(SOX-B)⇒ not before the end ofthe solar neutrinoprogram (2017 ?)At the center of thedetector (SOX-C), butneed a major upgrade ofthe detector
SOX-C [4]
Jonathan Gaffiot: CNRS / APC The SOX experiment 15 / 16
SOX: Short (distance neutrino) Oscillations with BoreXinoThe cerium experiment: CeSOX
The chromium experiment: CrSOXPerspectives and conclusions
Compared sensitivitySource activity measurementSchedule and perspectivesConclusions
Conclusions
SOX is designed to test unambiguously the short baseline oscillation hypothesis,searching for the oscillation as an energy and/or distance pattern
Two sources are planned: the 51Cr neutrino source and the 144Ce-144Prantineutrino source
The 144Ce-144Pr source has entered the production phase and is expected by theend of 2015 at LNGS
Important effort on calorimetry and 144Pr electron spectrum measurement tocontrol systematic uncertainties at the target level (at least 1.5%)
The 51Cr source will use the Gallex chromium and be irradiated twice at HFIR toget enough statistic, but the schedule is not fixed
Jonathan Gaffiot: CNRS / APC The SOX experiment 16 / 16
Back-upReferences
Back-up
Jonathan Gaffiot: CNRS / APC The SOX experiment 0 / 16
Back-upReferences
Cerium production 1
Jonathan Gaffiot: CNRS / APC The SOX experiment 1 / 16
Back-upReferences
Cerium production 2
Jonathan Gaffiot: CNRS / APC The SOX experiment 2 / 16
Back-upReferences
Cerium production 3
Jonathan Gaffiot: CNRS / APC The SOX experiment 3 / 16
Back-upReferences
Gallex
The Gallex source
Gallex enriched chromium shippedat Saclay
Jonathan Gaffiot: CNRS / APC The SOX experiment 4 / 16
Back-upReferences
References I
[1] A. Aguilar-Arevalo et al.Evidence for neutrino oscillations from the observation of anti-neutrino(electron) appearance in a anti-neutrino(muon) beam.Phys.Rev., D64:112007, 2001.
[2] A.A. Aguilar-Arevalo et al.Unexplained Excess of Electron-Like Events From a 1-GeV Neutrino Beam.Phys.Rev.Lett., 102:101802, 2009.
[3] A.A. Aguilar-Arevalo et al.Event Excess in the MiniBooNE Search for ν̄µ → ν̄e Oscillations.Phys.Rev.Lett., 105:181801, 2010.
[4] Davide Bravo.ν/ν̄ sources in borexino.ICHEP, July 2014.http://indico.ific.uv.es/indico/getFile.py/access?contribId=191&sessionId=26&resId=0&materialId=slides&confId=2025.
[5] Barbara Caccianiga.Future short baseline sterile neutrino searches with nuclear decays.XXVI International Conference on Neutrino Physics and Astrophysics, June 2014.https://indico.fnal.gov/getFile.py/access?contribId=296&sessionId=25&resId=0&materialId=slides&confId=8022.
[6] C. Giunti, M. Laveder, Y.F. Li, Q.Y. Liu, and H.W. Long.Update of Short-Baseline Electron Neutrino and Antineutrino Disappearance.Phys.Rev., D86:113014, 2012.
[7] Carlo Giunti and Marco Laveder.Short-Baseline Active-Sterile Neutrino Oscillations?Mod.Phys.Lett., A22:2499–2509, 2007.
[8] Carlo Giunti and Marco Laveder.Statistical Significance of the Gallium Anomaly.Phys.Rev., C83:065504, 2011.
Jonathan Gaffiot: CNRS / APC The SOX experiment 5 / 16
Back-upReferences
References II
[9] Patrick Huber.Determination of antineutrino spectra from nuclear reactors.Phys. Rev. C, 84:024617, Aug 2011.
[10] Patrick Huber.Erratum: Determination of antineutrino spectra from nuclear reactors [phys. rev. c 84, 024617 (2011)].Phys. Rev. C, 85:029901, Feb 2012.
[11] G. Mention et al.The Reactor Antineutrino Anomaly.Phys. Rev., D83:073006, 2011.
[12] Mikko Meyer.Search for sterile neutrinos with the borexino detector.PANIC, August 2014.https://indico.desy.de/getFile.py/access?contribId=7&sessionId=35&resId=0&materialId=slides&confId=8648.
[13] Th. A. Mueller, D. Lhuillier, M. Fallot, A. Letourneau, S. Cormon, M. Fechner, L. Giot, T. Lasserre, J. Martino, G. Mention,A. Porta, and F. Yermia.Improved predictions of reactor antineutrino spectra.Phys. Rev. C, 83:054615, May 2011.
[14] Marco Pallavicini.Borexino & sox.Princeton, January 2014.
[15] Michael Wurm.Experimental searches on sterile neutrinos.12th International Conference on Heavy Quarks and Leptons (HQL 2014), August 2014.https://indico.mitp.uni-mainz.de/getFile.py/access?contribId=33&sessionId=6&resId=0&materialId=slides&confId=23.
Jonathan Gaffiot: CNRS / APC The SOX experiment 6 / 16
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