The SOX experiment Jonathan Gaffiot on behalf of the SOX - - PowerPoint PPT Presentation
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX Outlook The chromium experiment: CrSOX Perspectives and conclusions The SOX experiment Jonathan Gaffiot on behalf of the SOX collaboration CNRS / APC
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Outlook
Jonathan Gaffiot
CNRS / APC
September 12, 2014
Jonathan Gaffiot: CNRS / APC The SOX experiment 1 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Outlook
1
SOX: Short (distance neutrino) Oscillations with BoreXino The scientific case The Borexino detector The SOX experiment
2
The cerium experiment: CeSOX Production Shielding and transport Signal and backgrounds
3
The chromium experiment: CrSOX Production Shielding and transport Signal and backgrounds
4
Perspectives and conclusions Compared sensitivity Source activity measurement Schedule and perspectives Conclusions
Jonathan Gaffiot: CNRS / APC The SOX experiment 1 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions The scientific case The Borexino detector The SOX experiment
1
SOX: Short (distance neutrino) Oscillations with BoreXino The scientific case The Borexino detector The SOX experiment
2
The cerium experiment: CeSOX Production Shielding and transport Signal and backgrounds
3
The chromium experiment: CrSOX Production Shielding and transport Signal and backgrounds
4
Perspectives and conclusions Compared sensitivity Source activity measurement Schedule and perspectives Conclusions
Jonathan Gaffiot: CNRS / APC The SOX experiment 1 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions The scientific case The Borexino detector The SOX experiment
3 anomalies at the ∼ 3σ level each
LNSD [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 |∆m2
new| ∼ 0.1 − 5 eV2
See talks of Patrick Huber, Michele Maltoni and Thierry Lasserre
NOBS/(NEXP)pred,new Distance to Reactor (m)
Bugey−3 ROVNO Bugey−4 Bugey3 Bugey3 Goesgen Goesgen Goesgen ILL Krasnoyarsk Krasnoyarsk−2 Krasnoyarsk−3 PaloVerde CHOOZ
10
1
10
2
10
3
0.7 0.8 0.9 1 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 BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions The scientific case The Borexino detector The SOX experiment
ref [12]
Deep underground laboratory: 1400 m ⇒ 3800 m.w.e. and 1.2 muons h−1 m−2
Jonathan Gaffiot: CNRS / APC The SOX experiment 3 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions The scientific case The Borexino detector The SOX experiment
Muon veto and radioactivity shielding 2.1 kt, r=9 m, 208 PMT
Radioactivity shielding 800 t, r=6.85m, 2212 PMT
Liquid scintillator (PC+PPO) 300 t, r=4.25m Stainless steel tanks Nylon vessels Stainless steel plates 10 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 BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions The scientific case The Borexino detector The SOX 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 BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions The scientific case The Borexino detector The SOX experiment
Neutrino source:
51Cr
Electron capture: 753 keV (90 %) and 433 keV (10 %) νe Half-life: 27.7 day Produced by neutron irradiation
Scattering on e− Backgrounds:
210Po, 210Bi, and 7Be solar νe
Activity: ∼ 10 MCi ⇒ 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: ¯ νe up to 3.00 MeV
144Ce half-life: 285 d
Extracted from nuclear spent fuel Inverse beta decay
Threshold 1.8 MeV Cross-section ∼ 10 times higher than νe Coincidence between e+ and neutron
∼ background free Activity: ∼ 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 BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Production Shielding and transport Signal and backgrounds
1
SOX: Short (distance neutrino) Oscillations with BoreXino The scientific case The Borexino detector The SOX experiment
2
The cerium experiment: CeSOX Production Shielding and transport Signal and backgrounds
3
The chromium experiment: CrSOX Production Shielding and transport Signal and backgrounds
4
Perspectives and conclusions Compared sensitivity Source activity measurement Schedule and perspectives Conclusions
Jonathan Gaffiot: CNRS / APC The SOX experiment 6 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Production Shielding and transport Signal and backgrounds
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 NPP
2
Cutting, digestion and PUREX process ⇒ lanthanides and actinides concentrate
3
Displacement chromatography ⇒ extraction of all cerium isotopes ∼ 5 kg
4
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 BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Production Shielding and transport Signal and backgrounds
2.185 MeV 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 ongoing From 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 BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Production Shielding and transport Signal and backgrounds
Eν (MeV) Arbitrary Unit
144Ce−144Pr antineutrino emitted spectrum in secular equilibrium
0.5 1 1.5 2 2.5 3 10
−2
10
−1
10
Counts per 0.10 m MeV−1 bin 2 3 4 5 6 7 8 50 100 150 200 250 300 350 400 450 500 No oscillations sin2(2θnew) = 0.10, ∆m2
new = 0.5 eV2
sin2(2θnew) = 0.10, ∆m2
new = 2 eV2
R/E (m MeV−1) Osc/No osc ratio 2 3 4 5 6 7 8 0.85 0.9 0.95 1
∆m2
new = 2.5 eV2 and sin2(2θ) = 0.16
Pattern in L and in E: shape-only signature + disappearance measurement Huge overburden and perfect material purity ⇒ no backgrounds except geoneutrinos and reactor neutrinos! Simulations show no source induced background
Jonathan Gaffiot: CNRS / APC The SOX experiment 9 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Production Shielding and transport Signal and backgrounds
1
SOX: Short (distance neutrino) Oscillations with BoreXino The scientific case The Borexino detector The SOX experiment
2
The cerium experiment: CeSOX Production Shielding and transport Signal and backgrounds
3
The chromium experiment: CrSOX Production Shielding and transport Signal and backgrounds
4
Perspectives and conclusions Compared sensitivity Source activity measurement Schedule and perspectives Conclusions
Jonathan Gaffiot: CNRS / APC The SOX experiment 9 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Production Shielding and transport Signal and backgrounds
ref [14]
Re-use of Gallex Cr, 36 kg enriched in
50Cr at 38 %
Irradiation planned at Oak Ridge HFIR Simulations ongoing to optimize activity: currently with 2 back-to-back cycles, 5–6 MCi are reached
Jonathan Gaffiot: CNRS / APC The SOX experiment 10 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Production Shielding and transport Signal and backgrounds
Due to the short period of 51Cr, the whole procedure below must not last more than 1 week
1
After irradiation, chromium is dispatched in hot cell between 3 capsules
2
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 Casaccia
4
Cr is gathered in 1 source in hot cell then inserted in a tungsten alloy shield
5
The source is transported to LNGS and mounted within the calorimeter
6
The whole system is inserted in the pit for 3 months
7
Repeat steps 1 to 6 to reach a total of 10 MCi
ref [14] Jonathan Gaffiot: CNRS / APC The SOX experiment 11 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Production Shielding and transport Signal and backgrounds
electron recoil energy [MeV] 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 # [per 133 t x 1 day x 0.1 MeV]
10 1 10
2
10
3
10
51
Cr
1 1
C pep-ν
7Be-ν 21 0Po
ref [15]
2 2 41 14 2
eV 2 Δm 0.3 2θ sin = =
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 BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Compared sensitivity Source activity measurement Schedule and perspectives Conclusions
1
SOX: Short (distance neutrino) Oscillations with BoreXino The scientific case The Borexino detector The SOX experiment
2
The cerium experiment: CeSOX Production Shielding and transport Signal and backgrounds
3
The chromium experiment: CrSOX Production Shielding and transport Signal and backgrounds
4
Perspectives and conclusions Compared sensitivity Source activity measurement Schedule and perspectives Conclusions
Jonathan Gaffiot: CNRS / APC The SOX experiment 12 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Compared sensitivity Source activity measurement Schedule and perspectives Conclusions
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 BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Compared sensitivity Source activity measurement Schedule and perspectives Conclusions
Main source activity measurement: calorimetry Cross-check with other methods based on sampling are foreseen Goal: the percent level (at least 1.5 %)
(multi layer insulation not represented)
Cerium calorimeter 1 day measurement before deployment Chromium calorimeter Continuous measurement during the experiment
Jonathan Gaffiot: CNRS / APC The SOX experiment 14 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Compared sensitivity Source activity measurement Schedule and perspectives Conclusions
Schedule February 2015: arrival of fresh nuclear fuel at Mayak November 2015: delivery of the cerium source by Mayak December 2015: start of 1.5 year of data-taking with 144Ce 2016+: chromium irradiation at HFIR Later: deployment of new sources inside Borexino! In the water volume (SOX-B) ⇒ not before the end of the solar neutrino program (2017 ?) At the center of the detector (SOX-C), but need a major upgrade of the detector
SOX-C [4]
Jonathan Gaffiot: CNRS / APC The SOX experiment 15 / 16
SOX: Short (distance neutrino) Oscillations with BoreXino The cerium experiment: CeSOX The chromium experiment: CrSOX Perspectives and conclusions Compared sensitivity Source activity measurement Schedule and perspectives 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-144Pr antineutrino source The 144Ce-144Pr source has entered the production phase and is expected by the end of 2015 at LNGS Important effort on calorimetry and 144Pr electron spectrum measurement to control systematic uncertainties at the target level (at least 1.5 %) The 51Cr source will use the Gallex chromium and be irradiated twice at HFIR to get enough statistic, but the schedule is not fixed
Jonathan Gaffiot: CNRS / APC The SOX experiment 16 / 16
Back-up References
Jonathan Gaffiot: CNRS / APC The SOX experiment 0 / 16
Back-up References
Jonathan Gaffiot: CNRS / APC The SOX experiment 1 / 16
Back-up References
Jonathan Gaffiot: CNRS / APC The SOX experiment 2 / 16
Back-up References
Jonathan Gaffiot: CNRS / APC The SOX experiment 3 / 16
Back-up References
The Gallex source Gallex enriched chromium shipped at Saclay
Jonathan Gaffiot: CNRS / APC The SOX experiment 4 / 16
Back-up References
[1]
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 ¯ νµ → ¯ νe Oscillations. Phys.Rev.Lett., 105:181801, 2010. [4] Davide Bravo. ν/ ¯ ν 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]
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-up References
[9] Patrick Huber. Determination of antineutrino spectra from nuclear reactors.
[10] Patrick Huber. Erratum: Determination of antineutrino spectra from nuclear reactors [phys. rev. c 84, 024617 (2011)].
[11]
The Reactor Antineutrino Anomaly.
[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]
Improved predictions of reactor antineutrino spectra.
[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