# Presentation: 188858

## MiniBooNE - Booster Neutrino Experiment at FermilabAndrew GreenIndiana University

**MiniBooNE - ****Booster Neutrino Experiment at Fermilab****Andrew Green****Indiana University**

- Moriond, EW Session					March, 2003

- nu2002.ps

** ****Motivation**
** ****Beam & Detector**
** ****Data Acquisition**
** ****Highlights**

## Current n Oscillation Measurements

**Well-established measurements:**
- Solar Dm2 ~10-(4~5)  eV2 from  ne         nx
- Atmospheric Dm2~3x103eV2  from nm         nx
**Needs Confirmation:**
- LSND Dm2~10-(0 ~ 1) eV2 from
- nm         ne

- Introduces 3 Dm2 values inconsistent with  3 neutrino families!!

- Posc = sin22q sin2(1.27Dm2L/E)

##    Enter MiniBooNE...

- Goal: Verify or rule out the LSND signal.
- Main Advantages over LSND:
- L/E same, but L, E ~ 10x larger
- 10x higher statistics.
- Better background understanding
- Larger detector volume.
- Cosmic ray hodoscope above.
- Better detector calibration
- Lower beam duty factor (lower background from cosmics)

## The BooNE Collaboration

- Y. Liu, I Stancu
*University of Alabama, Tuscaloosa, AL 35487*
- S. Koutsoliotas
*Bucknell University, Lewisburg, PA 17837*
- E. Church, C. Green, G. J. VanDalen
*University of California, Riverside, CA 92521*
- E. Hawker, R. A. Johnson, J. L. Raaf
*University of Cincinnati, Cincinnati, OH 45221*
- T. Hart, E. D. Zimmerman
*University of Colorado, Boulder, CO 80309*
- _J. M. Conrad_, J. Link, J. Monroe, M. H. Shaevitz, M. Sorel, G. P. Zeller
*Columbia University, Nevis Labs, Irvington, NY 10533*
- D. Smith
*Embry Riddle Aeronautical University, Prescott, AZ 86301*
- C. Bhat, S. J. Brice, B. C. Brown, L. Bugel, B. T. Fleming, R. Ford,
- F. G. Garcia, P. Kasper, T. Kobilarcik, I. Kourbanis, A. Malensek,
- W. Marsh, P. Martin, F. Mills, C. Moore, P. Nienaber, E. Prebys,
- A. Russell, P. Spentzouris, R. Stefanski, T. Williams
*Fermi National Accelerator Laboratory, Batavia, IL 60510*

- 62 Scientists from
- 13 institutions

- D. C. Cox, A Green, H. -O. Meyer, R. Tayloe
*Indiana University, Bloomington, IN 47405*
- G. T. Garvey, _W. C. Louis_,G. A. McGregor,  G. B. Mills, V. Sandberg, B. Sapp,
- R. Schirato, R. Van de Water, D. H. White
*Los Alamos National Laboratory, Los Alamos, NM 87545*
- R. Imlay, W. Metcalf, M. Sung, M. O. Wascko
*Louisiana State University, Baton Rouge, LA 70803*
- J. Cao, Y. Liu, B. P. Roe
*University of Michigan, Ann Arbor, MI 48109*
- A. O. Bazarko, P. D. Meyers, R. B. Patterson, F. C. Shoemaker
*Princeton University, Princeton, NJ 08544*

- 2 undergraduate universities
- 9 graduate universities
- 2 U.S. laboratories

## Sensitivity Goal

- MiniBooNE at 1-2 yrs of full intensity

-  With 1x1021 protons on target, MiniBooNE will cover the LSND signal region at the 5s level.
-  Fill area is highest likelihood region of  LSND's *affirmative result.*
-  Lines indicate * proposed exclusion region.*

## The neutrino beam

-  Primary beam of 8 GeV protons from Booster
-  Beryllium target produces secondary beam of pions and kaons
-  Horn focuses charged particles toward detector
-  The Little Muon Counter cross-checks the beam flux and measures ne background from K decays
-  Variable decay length of 50/25 m
-  Potential n running mode

## MiniBooNE Detector

-  Built to detect Cherenkov light
- 12 meter (40') diameter sphere
-  250,000 gallons of white mineral oil
- 	807 tons, 445 tons fiducial
-  Optically isolated inner region lined
- 	with 1280 PMTs (10% coverage)
-  Veto region with 240 PMTs
- Custom front-end electronics

- All new DAQ software

## Main Data Acquisition System

- PMT Charges (Q) and times (T) are digitized every 100ns ...info kept for 205ms (about 10x longer than needed) in a circular buffer for each channel.
- The trigger captures a time window (stored in the circular buffer) of Q & T data based on:
- External input pulses:  "protons to MiniBooNE," calibration, strobe signals
- Detector info: A few Nhit thresholds for Main & Veto
- PMT & Trigger data from VME crates are colated, monitored, and shipped.
- Other data streams: beam, horn, off-axis muon detector (LMC), beam pulse digitizer, slow monitoring.

## Particle ID

## Estimates of the MiniBooNE Signal 

-  ~500k nmC  CC events
-  ~50K nmC  NC

**Estimates of the MiniBooNE Signal **

## Status Highlights

- Cosmic & calibration data-taking since Dec 2001
- "Michel"-electron data (m    e nm) from cosmics: endpoint used to get partial energy calib.
- Beam data began Sept 2002
- Beam n data: ~40k n events collected so far (loose cuts).
- p0 peak seen: preliminary, but encouraging!

## Event Displays:  Gallery of Rings

## Cosmics, and other things

- Tank is inner region (1280 tubes)
- Veto is optically isolated outer region (240 tubes)
- Cosmics enter outer veto   region  first
- Rate consistent with known measurement.
- Check of veto efficiency
- Michel electrons decay from cosmic muons
- Important tool for calibration
- Well-understood.

## Michel Data

**"e"**

**"****m****"**

- Fit lifetime: 2.12 ± 0.05 ms
- Expected < 2.2 ms due to m-  capture on 12C.

## Neutrino candidates  

## p0 Mass Peak

**p****0**** Mass Peak**

- Select: beam n candidates with two good rings

- Example p0 candidate

## Summary

- MiniBooNE will confirm or rule out the LSND result.
- The detector is fully operational and taking n-beam data.
- We understand our cosmic & michel data
- We see neutrinos.
- We see a p0 peak in the neutrino data.

## End of Presentation.

- Backup slides follow...

## Slide 19

## Neutrino Beam/Event Timing

- Beam macrostructure

- Time

- - DAQ readout started with "booster extract" signal

- Beam microstructure

- Time

- - A cut is determined from beam microstructure
-    digitized at target.
- - Reduces "out -of-time" backgrounds

## n -Candidate Timing Relative to proton bunches.

-  n candidates in the detector line up well with a Booster proton bunch.
-  This greatly reduces external backgrounds.

## Beam Composition

-  Getting to know the flux:
- Detailed simulations
- HARP measurements
- nm-Carbon charged current s
- 50m & 25m decay region (m background)
- Off-axis muon counter, LMC (K background)

## Auxiliary Data

- Proton beam structure digitizer (reduce beam duty cycle).
- Little Muon Counter (LMC) data (understand some backgrounds)
- Beam Data (understand prot. flux for each event):
- MiniBooNE beamline
- Slow data -> Magnet currents
- Fast data (synch with proton pulse) -> Target multiwire detectors, beam position monitors, toroid (measures proton intensities)
- Horn & Target
- Horn current
- Temperature of the target
- 90° monitor (beam on target?)

## Calibration 

- PMT charges and times calibrated using laser and 4 flasks ludox.

- Trajectories of michel decays understood using muon tracking system and 7  scintillator cubes.

## Calibration Sources

- Cosmic Michel data
- Energy calibration
- Develop electron cuts
- Laser data
- PMT charge & time
- Detailed PMT hit structure
- Muon hodoscope, scintillator cubes (7)
- Precise michel trajectory through the detector correlate to PMT data

## Background measurements in the beamline

- Little Muon Counter: A spectrometer which exploits the wide-angle
- decays of the Kaon, and will get the m energy distribution to constrain
- the ne production rate from Kaons.

- Varying the length of the decay region from 50m to 25m :
-  An oscillation signal would go down by factor of 2.
-  Background ne rate (m decay) would go down by a factor of 4.
-  ne 's from decay of short-lived sources not affected.

## Fermilab Booster

-  Supplies 8 GeV protons to the lab
-  Currently supplying to collider programs (Run II) & MiniBooNE without affecting Run II luminosity.
-  Operating at record intensities of      ~5 x 1012 protons/pulse,
-  Goal average pulse rate to MiniBooNE is 5 Hz, currently at ~3Hz.
-  Rate is mostly limited by radiation losses which are gradually being addressed.

## Target & Horn

-  Beryllium target, 71 cm long.
-  Resides on the horn axis of symmetry.
-  Air cooled -> air temperature correlates to beam on target.

-  170 kA, 140 ms waveform, 5 Hz average rate (15 Hz burst rate).
-  Life expectancy is 200 M pulses, and tested with 11 M.
-  Installed & running with beam since early September.
-  H2O cooled 1 liter/sec  (2.4 kW heat load).

## DAQ Overview

## Supernova "Trigger"

- 200 ne p    e+ n events for a Milky Way supernova at 10 kpc.
- Trigger: 15 ms holdoff from cosmics & no hits in veto region.
- 12B decay background peaked at lower energy, cosmic ray background peaked at higher energy (M. K. Sharp, J. F. Beacom, J. Formaggio, **hep-ph/0205035)**

## Slide 31

## Goal

- Make a high intensity nearly pure nm beam of known spectrum and flux.
- Build a mineral oil detector to analyze the beam n's.
- Ask:  Do we see a ne spectrum in addition to that expected in the beam?
- If so, measure the oscillation probability of  nm        ne
- In addition, make other measurements.

## Neutrino Oscillations