MiniBooNE Status Report Ray Stefanski for the MiniBooNE Collaboration.
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Transcript of MiniBooNE Status Report Ray Stefanski for the MiniBooNE Collaboration.
Seventh International Workshop on
TOPICS IN ASTROPARTICLE AND UNDERGROUND
PHYSICSSeptember 8-12, 2001
Laboratori Nazionali del Gran Sasso, Assergi (ITALY)
MiniBooNE Status ReportRay Stefanski
for the MiniBooNE Collaboration.
in four movements.
The road to e oscillations with MiniBooNE
Medium baseline oscillation detectors? pascaglia What we expect to observe and when? minueta How are we doing? sonata alegro Summary & conclusions coda
LSND: e 20020 E
MeV
decay at rest
e MeV
6020 E
decay in flight
Final results, 1993-98 data; event excess; evidence for oscillations.
KARMEN: e
6020 E
MeV decay at rest.
Experiment ended March 2001; no excess; does not confirm LSND, but does not rule it out either.
MiniBooNE: e 1500500 E MeV
Under construction; first data summer 2002; will confirm/rejectLSND at the five sigma level.
8 GeV protons, 3 GeV
LSND and KARMEN(M. Steidl) are precursor experiments to M’BooNE, the “Mini” Booster Neutrino Experiment.
pascaglia
LSND and KARMEN experimental scheme
ee
emuon decay at rest
nepe detect prompt e track, 20<Ee<60 MeV
neutron capture: dnp 2.2 MeV, ),( nGd 8 MeV
correlated in position and in time with eno B-field, e and sequence distinguishes e+ from e
pascaglia
LSND
Beam onoff excessevents 4.229.117
events 9.35.19 DAR :bkgd events 6.45.10 DIF
Total excess:
events 0.64.229.87
Excess for 100% transmutation: events 333033300 Oscillation probability 0.045)%0.067(0.264
MeV 6020 eE Rlikelihood that is correlatedlikelihood that is uncorrelated
pascaglia
• MiniBooNE addresses the LSND signal.•Oscillations imply
o neutrinos have a mass spectrum;o neutrinos flavor mix.
• The LSND result is in the “cosmologically interesting” region;• MiniBooNE is unique in fully addressing this signal.
e
Search for neutrino oscillationsat higher m2.
2m
Hot dark matter.Formation of galaxies.
pascaglia
We expect that a greatdeal will be understoodin the next five yearsregarding oscillationsand mass.
Clarification of the LSNDregion is crucial for anunderstanding of theseissues.
pascaglia
By 2004 data from MiniBooNE, SNO and Kamland should shedconsiderable light on this picture.
o There are many models for sterile neutrinos, and the existence ofsterile neutrinos immediately implies new physics.
o In the next five years, we would like to observe oscillatorybehavior, and clarify the sterile neutrino issue.
pascaglia
An Overview of MiniBooNE
Alabama – Bucknell – Cincinnati – Columbia – Embry-Riddle Holy Cross – Indiana – LouisianaMichigan – Princeton – Riverside
FNAL - LANL
Uses an intense neutrino beam with mean energy at ~1 GeVto detect the appearance of electron neutrinos in a relativelypure muon neutrino beam. The detector is a 12 meterdiameter Cerenkov detector filled with mineral oil.
Muon monitors
minueta
The Booster
8 GeV proton accelerator built to supply beam to the Main Ring, it now supplies the Main Injector
Booster must now run at record intensity
MiniBooNE will run simultaneously with the other programs:e.g. Run II + BooNE; 5 x 1012 protons per pulse at a rate of 7.5 Hz; (5 Hz for BooNE)
BooNE: 5 x 1020 p.o.t in one year
Challenges are radiation issues, losses
minueta
Beam-line civil construction:
• In only a few months, the excavation has been filled with a beam tunnel.• The project is ready for some early tunnel installation.
• Progress is adequate for first beam in the spring.• Some of the initial runs will be devoted to systems checkout.
minueta
Horn & Target System• 20M pulse tests of proto-horn are about to begin. Initial 170 kamp, 5 Hz runs have been made.• An aluminum proto-target is available for these tests. Beryllium target will be available in December.
• The horn power supply is complete.• The water cooling system is complete.
minueta
Target Hall & Decay Pipe
Construction was delayed because of heavy snow during the winter and difficulty with our contractor.
This enclosure willcontain the target, horn, andassociated shielding. Above theenclosure will sit a service building that will contain a 30 Tcrane.
minueta
Muon monitors
The little muon counterto measure muons fromK – decay.
The muon detector, to act as abeam monitor.
minueta
MiniBooNE detector
mineral oil
total volume: 800 tons (6 m radius)fiducial volume: 445 tons (5m radius)
1280 PMTs in detector at 5.5 m radius
10% photocathode coverage 240 PMTs in veto
Phototube support structure provides opaque barrier between veto and main volumes
Sonata alegro
tiondiscrimina ,, :Analysis 0e
PID based on ring id, track extent, ratio of prompt/late light signatures substantially different from LSND x10 higher energy neutron capture does not play a role
If LSND correct: ~500 events (2 years)
Backgrounds are mis-id of ’s and ’s, and intrinsic e in the beam
Sonata alegro
Oil Tester We’ve received samples of oil from potential vendors. These samples will be tested to find the best oil.
A beam of light of given wavelength is passed through air, and a tube of oil. Transmission as a function of wavelength is measured for each oil. Procurementdecision will be made in about a month.
Sonata alegro
PMTs
Most of the 1500PMTs have been installed in the detector.
This photo showsThe PMTs ready forinstallation. Note thewire mounting bracket,and potted bases.
All of the LSND tubes tested well. A few of the new batch of 300 had faults.
Sonata alegro
MiniBooNE statusSonata alegro
Virtually all PMTs are installed.Tests will be done with the tank empty, and using flashers.
Most of the cablesare installed, electronics are progressing, and work continues on DAQ.
Sonata alegro
Signal vs. Background
Coda
Coda
C* ???
Summary
LSND observes appearance of oscillations at relatively high and low mixing angle
e 2m
This observation needs confirmation.
MiniBooNE will start collecting data in spring 2002, and will make a definitive statement about LSND after two years.
Coda