# Presentation: 170592

## MiniBooNE:Status and Plans

- Outline
- Physics motivation
- Beamline performance
- Detector performance
- First look at the data
- Conclusions

*Fernanda G. Garcia, Fermilab*
*URA visit, March 14, 2003*

## Search for neutrino oscillations

*Search for neutrino oscillations*

- LSND signal region
- KARMEN II
- MiniBooNE

- at high m2

- e

## The LSND Experiment:

- Copper beamstop

- Beamline 30m
- Neutrino energy
-   20-55 MeV

- 800 MeV proton beam

- water target

- L/E = 1m/MeV
- 167 tons of mineral oil
- 1280 photomultipliers

- 

- e+ e

- ife

- e p e+ n

- n p  d eV

- e

## LSND Result

-  Signal above background
- 87.9   22.4  6.0 events

-  Oscillation probability
-   (0.264 0.067  0.045) %

## Neutrino Oscillations Scenario

- 3 separated m2 regions
-    interesting situation...

- add a 4th neutrino (or more)

- ... or other explanations like

- (Barenboim *et.al.(*Phys.Lett.B534:106.2002)

- CPT

- Needs confirmation

- MiniBooNE

## Slide 6

## The BooNE Collaboration

- 62 scientist from 13 institutions
- 2 Undergraduate institutions
- 9 Graduate institutions
- 2 National laboratories

## The MiniBooNE beamline

-   8 GeV protons from the FNAL Booster
-                    strikes a Be target
-                                 producing mesons decay
-                                             neutrinos traverse 450 m of dirty
-  				                     reaching the detector

## Exciting time for the Booster

-   Many improvements happened since August'02
-   Dedicated study periods have enlightened our understanding
-        of the machine
-   New record achieved in February 06
-      after lifting up extraction
-      septum magnet

- 3.5E12 protons/pulse

- 5.65E16 protons/hour

## Booster performance

- Total Booster Output (protons/minute)

- Energy Lost per Proton  (W-min/proton)

- MiniBooNE

- Tune to reduce dogleg currents

- Test with one dogleg off (halfway to MiniBooNE goal!)

## Beamline performance

- easured and predicted changes
-   of central trajectory along beamline

- Calculated beam envelope
- with measurements overlayed

*We understand our beam optics*

## Horn and target system

- Current: 170 KA
- Rep rate: 5 Hz
- Design lifetime: 200 million pulses
- Up to now: 9.6 million pulses
- Toroidal magnetic field focuses positive 		particles (mode)
- Can switch polarity to focus negative
- 	particles ( mode)

-  - 71 cm long Be target
-  - Resides inside the horn
-  - The target was calibrated for       	production at HARP                                                (CERN)
- 	(20.6 million triggers)

## Understanding beam backgrounds

-   Intrinsic e's from   decays

*Signal and background behave differently*
*        **by varying the length of decay pipe *
* *Signal proportional to L*decay*
-  Background proportional to L2*decay*

-   Intrinsic e's from Kaons decay (K+,KL)

- Little muon counter

*Backgrounds are mis-id of*
***'s and ****'s*
*and intrinsic ****e** in the beam*

## Neutrino flux at the detector

- L/E ~ 1m/MeV

- Flux estimate is crucial

- 8 GeV protons on Be
-   p  Be L
- yields a high beam
- +  +
- KL0
- with low e component
- + e+e
-   K+  0e+e, KL0 -e+e

## Absolute neutrino flux

-   Applied cuts
-     - Tank hits > 200
-      - Veto hits < 6
-      - Fiducial volume < 450 cm
-      -  4.5s < Event time < 6.5s
-   Total protons on target 7.96E18
-   Normalization error from
-      protons on target: 2%
-   # events: 3940

**Preliminary**

## MiniBooNE Detector

-   12 m spherical stell tank
-   250,000 gallons of pure mineral oil
-   Total volume: 800 tons
-      Fiducial volume: 445 tons
-                                 (5m radius)
-  1280 PMT’s in the detector region
-         10% photocathode coverage
-  240 PMT's in the veto region

## Detector reminiscence

- Last tube installed
- October 19, 2001
-          (8 months total)

- First oil railcar delivered
-      in December’01
-                 (5 months total)

- Topping off
- detector in
- June 24th 02

## Monitoring the oil

-    Oil samples are taken regularly
-    Attenuation length:  *L*att = 25.06±1.9m

***il samples are tested for oxygen on a regular basis*

- Dissolved gas

- O2/N2 ratio

## Electronics performance

- operational
- electronics channels
-  Dark noise ~ 1KHz
-  0.7% dead PMT’s.
-   New PMT’s dying at
- a rate of ~ 0.5%/yr

*This is****as good or better*
*                       **than other experiments!*

## DAQ and Trigger

-   Average trigger rate ~23 Hz
-     Beam rate 2-5 Hz
-    DAQ uptime ~ 98%
-    Variety of internal triggers
-      are implemented

## Muon tracker provides

- direction of the
- cosmic ray muons

- Cubes give position
- measurement of
- stopping muons and
- decay electrons

- 4 flasks filled with ludox
-   at different locations in the tank
- Provide PMT gain and timing

- Cubes trigger
- implemented during
- Jan shutdown.
- At the first order,
- trigger is working

## Calibration system: laser

- new PMT

- old PMT

- Single p.e.Timing Resolution

- 

- 

- new PMT

- old PMT

- Time (ns)

- Entries (# tubes)

- Time offset constants

*These values are*
*applied so calibration time*
*of laser hits is uniform*
*across all tubes*

- Time (ns)

- Time slewing constants

- old PMT

- new PMT

*Low charge pulses*
*  **need additional *
*time correction*

- Good agreement with bench tests

## Calibration:Michels

- Michel and Monte Carlo comparison

- Michel e-energy spectrum

-   The end point indicates
- 14.8% energy resolution

*Using decay electrons from cosmic muons*
*                                             **to determine energy scale*

## Events in the detector 

- Muon
- candidate

- Contained
- muon
- candidate

- 0 candidate

- Neutrino interactions
-  in oil produces
- Cerenkov light (prompt)
- Scintillation light (late)

- Preliminary

## First events from beam data

**First events from beam data**
**(Labor day weekend)**

- Simple cuts applied
- > 200 hits in the main region
- < 6 hits in the veto region

- 1.6 s

- Direction cosine of track
- from beam direction (Z)

-  CC candidate from the Labor day weekend

## First look at0 mass

- First look at0 mass

-  Cuts applied:
- - Tank hits >200
- - Veto hits < 6
- - 2 rings > 10 p.e. each
-  1.6 s beam window

-  Using, we can check
- 	the energy calibration                      	          		above michels

- pp 0
- n n 0

- 

- 0 NC production

- ...and it is there!

## What do we know about low energy neutrinos cross sections?

- We collected ALL possible
-    low energy neutrino data
-     to check cross sections model and kinematics

- Check rates for various  interactions

## And we are accumulating protons...

*And we are accumulating protons**...*

- _Record week: _
- Feb 24th  with 4.28E18
- protons delivered

- Total protons delivered
-            4.16E19

*~ 30% of the total protons*
*delivered were collected*
*after Jan shutdown. *

##  Conclusions

-  MiniBoone is taking data and is doing well!
-  Neutrino events look as expected
-  We are in the process of understanding our calibration
-        and reconstruction algorithms