solar neutrino at kamland
DESCRIPTION
Solar Neutrino at KamLAND. Sei Yoshida Reserch Center for Neutrino Science, Tohoku Univ. for the KamLAND Collaboration. Reactor Neutrino. Solar Neutrino. KamLAND. Geo-neutrino. KamLAND Experiment. - PowerPoint PPT PresentationTRANSCRIPT
2007 March 21st LAUNCH Workshop @ MPI, Heiderberg 1
Solar Neutrino at KamLANDSolar Neutrino at KamLAND
Sei YoshidaSei YoshidaReserch Center for Neutrino Science, Tohoku Univ.Reserch Center for Neutrino Science, Tohoku Univ.
for the KamLAND Collaborationfor the KamLAND Collaboration
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 2
KamLAND ExperimentKamLAND Experiment
Reactor NeutrinoReactor Neutrino
Geo-neutrinoGeo-neutrino KamLANDKamLAND
Solar NeutrinoSolar Neutrino
Confirmed oscillation of reactor anti-neutrino, firstly detected anti-Confirmed oscillation of reactor anti-neutrino, firstly detected anti-neutrino from the earth.neutrino from the earth.
Next step, Next step, 77Be solar neutrino detectionBe solar neutrino detection
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 3
KamLAND DetectorKamLAND Detector
Kamiokamine overburden : 2700m.w.e.Kamiokamine overburden : 2700m.w.e.
Muon rate : 0.34HzMuon rate : 0.34Hz
1000 tons of Liquid Scintillator1000 tons of Liquid Scintillator
Mineral Oil : Buffer against external BGMineral Oil : Buffer against external BG
1979 PMTs(17” 1325 + 20” 554)1979 PMTs(17” 1325 + 20” 554)
Photocathod caverage : 34%Photocathod caverage : 34%
Outer water Cherenkov detector for muon Outer water Cherenkov detector for muon vetoveto
KamLAND KamLAND DetectorDetector
1 kt Liquid Scintillator1 kt Liquid Scintillator
PMTsPMTs
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 4
Solar Neutrino DetectionSolar Neutrino Detection
Anti-neutrino detectionAnti-neutrino detection
Small BackgroundSmall Background
Neutrino detectionNeutrino detection
High level of BackgroundHigh level of Background
Delayed coincidence signatureDelayed coincidence signature Single unspecific signatureSingle unspecific signature
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 5
Internal Background of KamLANDInternal Background of KamLAND
At present
Single energy spectrum observed in KamLAND Single energy spectrum observed in KamLAND
4 m fiducial volume cut to suppress 4 m fiducial volume cut to suppress 4040K and K and 208208Tl external BGTl external BG
What is remeined background in single energy spectrum? What is remeined background in single energy spectrum?
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 6
Internal Background of KamLANDInternal Background of KamLAND
Main sources of background in the range of Main sources of background in the range of 77Be neutrinoBe neutrino210210Pb(Pb( 210210Bi Bi 210210Po ) Po ) by distillation by distillation8585Kr Kr by N by N22 purging purging
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 7
Required Reduction by PurificationRequired Reduction by Purification
222222Rn 3.8 d < 1mBq/mRn 3.8 d < 1mBq/m33
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 8
R&D Study for DistillationR&D Study for Distillation
Test Apparatus @ Tohoku Univ.Test Apparatus @ Tohoku Univ.AchievementAchievement
Impurity ReductionImpurity Reduction210210Pb ~7×10Pb ~7×10-5-5
4040K > 4×10K > 4×10-2-2
8585Kr ~1×10Kr ~1×10-6-6
3939Ar ~1×10Ar ~1×10-6-6
Almost acheived required levelAlmost acheived required level
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 9
Expected Spectrum after Expected Spectrum after PurificationPurification
210Pb :7.7×10-5 40K :3.8×10-2 85Kr :1.0×10-6
39Ar :1.0×10-6
11C
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 10
New Purification SystemNew Purification System
Construction finishedConstruction finished
Test operation to tune up parametersTest operation to tune up parameters
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 11
Concept of New Purification Concept of New Purification SystemSystem
Distillation SystemDistillation System NN22 Purge Towers Purge Towers
NN22 Generator Generator
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 12
Distillation SystemDistillation System
Liquid scintillator(LS) is fed into small buffer tank (2mLiquid scintillator(LS) is fed into small buffer tank (2m33)from )from KamLAND.KamLAND.
Different boiling pointDifferent boiling point
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 13
Distillation System (PC tower)Distillation System (PC tower)
Pseudocumene(PC) is distilled firstlyPseudocumene(PC) is distilled firstlyOperating pressure 2kPa.Operating pressure 2kPa.
Boiling point ~ 60Boiling point ~ 60℃ ℃
Rest at the bottom of PC tower Rest at the bottom of PC tower Dodecane + PPO Dodecane + PPO send to next towersend to next tower
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 14
Distillation System (NP tower)Distillation System (NP tower)
Dodecane(NP) is distilled secondly.Dodecane(NP) is distilled secondly.Operating pressure ~2kPa.Operating pressure ~2kPa.Boiling point ~ 100Boiling point ~ 100℃ ℃
Rest at the bottom of NP tower Rest at the bottom of NP tower Dodecane + PPO(little concentrated) Dodecane + PPO(little concentrated) send to PPO concentrator (~140send to PPO concentrator (~140℃ ℃ under 2kPa), NP is evaporated back to NP under 2kPa), NP is evaporated back to NP tower.tower.
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 15
Distillation System (PPO tower)Distillation System (PPO tower)
PPO is distilled finally.PPO is distilled finally.Operating pressure ~0.6 kPa.Operating pressure ~0.6 kPa.
Boiling point ~ 190Boiling point ~ 190℃ ℃
Rest at the bottom of PPO tower Rest at the bottom of PPO tower Exhaust Exhaust
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 16
Distillation System (Mixture tank)Distillation System (Mixture tank)
LS is mixed(blended) withLS is mixed(blended) with distilled PC,NP, and PPO. distilled PC,NP, and PPO.
Temperature senser and Density meterTemperature senser and Density meterPC and NP mixture is adjusted by pre-small tank.PC and NP mixture is adjusted by pre-small tank.
PPO is mixed with PC ~ 10 wt%, then fed into mixture tank.PPO is mixed with PC ~ 10 wt%, then fed into mixture tank.
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 17
Distillation System (Purge towers)Distillation System (Purge towers)
Purging by pure NPurging by pure N22 gas gas
Operating pressure ~ 40 kPa Operating pressure ~ 40 kPa
NN22 flow rate 30 ~ 35 Nm flow rate 30 ~ 35 Nm33/h/h
Series of “Gas – Liq. Mixer”, and “Gas-Liq. Separator”Series of “Gas – Liq. Mixer”, and “Gas-Liq. Separator”
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 18
NN22 Generator Generator
Newly developed/constructed NNewly developed/constructed N22 generator generatorSupply air : Rn less air from outside of mineSupply air : Rn less air from outside of mine
NN22 supply capacity : 40 Nm supply capacity : 40 Nm33/h/h
Emergency 5 NmEmergency 5 Nm33/h/h
PurityPurityAr 0.02 ~ 0.03ppm (measured)Ar 0.02 ~ 0.03ppm (measured)Kr ~10Kr ~10-15 -15 (not measured yet)(not measured yet)222222Rn ~ 5Rn ~ 5Bq/m3 (measured at purif. Area)Bq/m3 (measured at purif. Area)
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 19
Monitoring QualityMonitoring Quality
Background ReductionBackground Reduction
Reduction factors for Reduction factors for 210210Pb and Pb and 4040K will be monitored by KamLANDK will be monitored by KamLANDThe data will be continuously taken during purification.The data will be continuously taken during purification.
Rn concentration in purified LSRn concentration in purified LSDelayed coincidence of Bi-Po Delayed coincidence of Bi-Po miniLAND miniLAND
Electrostatic collection method after trappingElectrostatic collection method after trapping
Reduction factor of Reduction factor of 8585KrKrThe system is now tuning.The system is now tuning.
Optical propertyOptical property
Attenuation length after distillationAttenuation length after distillation
Light outputLight output
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 20
Monitoring Rn Concentration –Monitoring Rn Concentration –miniLAND--miniLAND--
miniLAND ; miniture version of KamLANDminiLAND ; miniture version of KamLAND0.4m0.4m33 of acrylic container ( 4×4 cells) of acrylic container ( 4×4 cells)
NaI solution as light guide to shield radiation from PMTsNaI solution as light guide to shield radiation from PMTs
Pb shield of 15 cm in thicknessPb shield of 15 cm in thickness
Borated PE of 5 cm in thicknessBorated PE of 5 cm in thickness
Measuring Rn concentration by Bi-Po delayed coincidenceMeasuring Rn concentration by Bi-Po delayed coincidenceSensitivity < 1 mBq/mSensitivity < 1 mBq/m33
It can also monitor,It can also monitor,Light outputLight output
Attenuation lengthAttenuation length
System is now readySystem is now ready
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 21
Rn Measurement SystemRn Measurement System
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 22
Rn Concentration in NRn Concentration in N22 Gas Gas
Purification AreaPurification AreaKamLANDKamLAND
Piping line between purification area and NPiping line between purification area and N22 generator, ~100m generator, ~100m
Rn emanation Rn emanation consistent with designed value ~ 5 consistent with designed value ~ 5Bq/mBq/m33
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 23
Monitoring Attenuation LengthMonitoring Attenuation LengthLight beam is collimated onto different wavelength filters.
For each of 21 different liquid heights along the 1 m long Stainless Steel tube (which is coated to minimize scattering) we take the following measurements:
PMT Dark current, measured by using a plug in the filter wheel
Beam intensity using photo-diode
PMT current for each wavelength filter (10 filters from 313 -550 nm)
Height is measured by differential pressure gauge and is calibrated for different liquid densities.
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 24
Results for Purified LS (MO/PC/PPO)Results for Purified LS (MO/PC/PPO)
We can already make LS by distilled PC/NP/PPO.We can already make LS by distilled PC/NP/PPO.
No significant deterioration for attenuation length No significant deterioration for attenuation length Compareing att. length Compareing att. length beforebefore and and afterafter distillation distillation
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 25
Present Status of PurificationPresent Status of Purification
Pseudocumene and Dodecane are successfully and stably distillated for a Pseudocumene and Dodecane are successfully and stably distillated for a period longer than a month.period longer than a month.
PPO tower operates as expected, however, stable/continuous operation PPO tower operates as expected, however, stable/continuous operation has not been achieved yet.has not been achieved yet.
Complete operation of full system will be tested soon, probably within a Complete operation of full system will be tested soon, probably within a month.month.
Quality of purified(distilled and purged) scintillator were measured, no Quality of purified(distilled and purged) scintillator were measured, no detectable impurities/deterioration has been measured/observed.detectable impurities/deterioration has been measured/observed.
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 26
Purification SchedulePurification Schedule
Recirculation test (soon, within a month)Recirculation test (soon, within a month)Recirculate small amount of LS into KamLAND to test this process without any Recirculate small amount of LS into KamLAND to test this process without any purification process.purification process.
After stable PPO tower operation ( probably within one or two months), After stable PPO tower operation ( probably within one or two months), recirculation distillated LS into KamLAND using the online distillation recirculation distillated LS into KamLAND using the online distillation systemsystem
To test recirculation process comletelyTo test recirculation process comletely
To check the quality of distilled LS further, recirculate ~50mTo check the quality of distilled LS further, recirculate ~50m33 of distilled LS into of distilled LS into KamLANDKamLAND
Regular distillation process, but …..Regular distillation process, but …..Full volume replacement will require ~ two months.Full volume replacement will require ~ two months.
Unfortunately, there is a time constraint because of scheduled blaster in the mine Unfortunately, there is a time constraint because of scheduled blaster in the mine to install new XMASS facility.(very clese to new purification site).to install new XMASS facility.(very clese to new purification site).
Previously, we requested a delay to the end of March 2007.Previously, we requested a delay to the end of March 2007.
We are now negotiating further delay in blasting activity.We are now negotiating further delay in blasting activity.
2007 March 21stLAUNCH Workshop @ MPI, Heiderberg 27
SummarySummary
LS purification system was constructed.LS purification system was constructed.
Part of operation is successfully running.Part of operation is successfully running.
Monitoring system of LS Quality after purification is almost ready.Monitoring system of LS Quality after purification is almost ready.
There is a time constraint.There is a time constraint.