H A R PA Hadron Production Experiment at the

Proton Synchrotron at CERN

Motivation for the HARP experiment

The HARP Detector

MiniBooNE and HARP

Università degli Studi e Sezione INFN, Bari, ItalyRutherford Appleton Laboratory, Chilton, Didcot, UK Institut für Physik, Universität Dortmund, GermanyJoint Institute for Nuclear Research, JINR Dubna, RussiaUniversità degli Studi e Sezione INFN, Ferrara, ItalyCERN, Geneva, Switzerland Section de Physique, Université de Genève, SwitzerlandLaboratori Nazionali di Legnaro dell' INFN, Legnaro, ItalyInstitut de Physique Nucléaire, UCL, Louvain-la-Neuve, BelgiumUniversità degli Studi e Sezione INFN, Milano, ItalyP.N. Lebedev Institute of Physics (FIAN), Russian Academy of Sciences, Moscow, RussiaInstitute for Nuclear Research, Moscow, RussiaUniversità "Federico II" e Sezione INFN, Napoli, ItalyNuclear and Astrophysics Laboratory, University of Oxford, UKUniversità degli Studi e Sezione INFN, Padova, Italy LPNHE, Université de Paris VI et VII, Paris, FranceInstitute for High Energy Physics, Protvino, RussiaUniversità "La Sapienza" e Sezione INFN Roma I, Roma, ItalyUniversità degli Studi e Sezione INFN Roma III, Roma, ItalyDept. of Physics, University of Sheffield, UKFaculty of Physics, St Kliment Ohridski University, Sofia, BulgariaInstitute for Nuclear Research and Nuclear Energy, Academy of Sciences, Sofia, BulgariaUniversità di Trieste e Sezione INFN, Trieste, ItalyUniv. de Valencia, Spain

HARP Institutions

HARP Motivation (general)

Measure absolute inclusive cross-sections for Hadron production with a range of targets (H,D,Be,C,O,N,Al,Sn,Ta,Pb)and primary proton energies (1.5 GeV/cto 15GeV/c).

HARP Motivation (specific)

● Neutrino Factory Design

• Atmospheric Neutrino Flux Calculations

• Neutrino Fluxes for MiniBooNE and K2K

• Input to Monte Carlo simulation packages

Neutrino Factory

Need to Know:

1. + , - production rates for varying target materials, target size and proton beam energies (2-24GeV).

2. The PT distribution with high

precision to optimize muon collection.

Atmospheric Neutrinos

_

Need to Know:

1. Primary Cosmic Ray Flux*

2. Hadron Interaction Model**

* known to better than 10%

**limited data leads to ~30% uncertainty in atmospheric neutrino fluxes

HARP at the CERN PS

• 200 meters in diameter• 28 GeV maximum energy• Feeds into SPS• Used to make anti-protons• Used for target expr. - HARP

HARP at the CERN PS

East Hall

T9 Secondary Beam at PS

• PS protons hit a target producing secondary particles.

• Particles are momentum selected allowing HARP to choosebeam energy (2 -15 GeV).

• However, beam consists of different particles - mainly protonsand pions.

• TOF measurements distinguish different particles in the beambefore hitting the HARP target.

NOTE: This is different from MiniBooNE. MiniBooNE gets 8 GeV protons directly from the Booster.

HARP Detector

HARP Detector

HARP detector: Acceptance, PID, Redundancy

TPC, momentum and PID (dE/dX)at large Pt

TPC, momentum and PID (dE/dX)at large Pt

Drift Chambers:Tracking and low Pt spectrometer

Drift Chambers:Tracking and low Pt spectrometer

1.5 T dipole spectrometer1.5 T dipole spectrometer

Threshold gas Cherenkov: identification at large Pl

Threshold gas Cherenkov: identification at large Pl

0.7T solenoidal coil0.7T solenoidal coil

Target-TriggerTarget-Trigger

EM filter (beammuon ID andnormalization)

EM filter (beammuon ID andnormalization)

Drift Chambers:Tracking

Drift Chambers:Tracking

TOF: identificationin the low Pland low Pt region

TOF: identificationin the low Pland low Pt region

HARP Detector

TPC:- PID- momentum measurement for high pT particles NDC:-Momentum measurement for low pT forward particlesCherenkov:- PID for momentum >3.0 GeV/cTOF:- PID primarily for p < 3.0 GeV/c

HARP Detector

Time Projection Chamber - TPC

10-1 1 10 p(GeV/c)

Used for particle id:• /K up to 0.7 GeV/c• /p up to 1.2 and above 3 GeV/c• want dE/dx resolution ~6%And momentum measurement:• r-resolution of 300 m• pT resolution dpT/pT=0.033 pT

TPC Hits,ArCO2 Mixture,0.7T Field,10 cm C Target

Prototype of the TPC simulation in the GEANT4 framework

Resistive Plate Chamber -RPC

HV

HV

+ + + ++

+ + + ++

+ + + ++

+ + + ++

Gas

Gas

TPC & RPC

TPC - RPC Event

HARP Detector

Drift Chambers & Spectrometer Magnet

• 0.5 T Vertical Field for momentum spectrometry• Vertical, +5°, -5° wire orientation in drift chambers• 90% Argon, 5% CO

2, 5% CH

4 gas mixture

• 150m - 700m resolution depending on incident angle• Typical single chamber efficiency of 97% (~90%)• Current momentum resolution is ~150 MeV at 3GeV

+

-

Drift Chambers & Spectrometer Magnet

HARP Detector

Threshold Cerenkov Detector• Filled with C

4F

10 (perflourobutane) at atmospheric pressure.

• Discriminates between protons and pions at high momentum.• At high beam momentum, strange particles (kaons) are also created.

C4F

10 properties:

n = 1.001415pion threshold = 2.6 GeV/ckaon threshold = 9.3 GeV/c

proton threshold = 17.6 GeV/c

HARP Detector

TOF Wall, Electron Identifier,Cosmic Trigger Wall,Beam Muon Identifier

TOF Wall - plane of scintillator counters to discriminate between protons and pions at low momentum

t ~ 210 ps)

-separation up to 4.6 GeV/c for /p 2.4 GeV/c for /K

Electron Identifier - lead-scintillating fiber counters to discriminate between hadrons on the one hand, and photons and electrons on the other.

Cosmic Trigger Wall - plane of scintillator sheets to trigger on cosmic muons for monitoring and calibration.

Beam muon Identifier - iron-scintillator calorimeter to identify beam muons.

TPCTPC

TOFTOF

CherenkovCherenkov

p/ separation at 4level, “conservative” simplification

PT vs. P

L Box Plot for pion Production on Be (@15GeV)

HARP Targets

Beryllium Carbon Aluminum Copper Tin Titanium Lead

}

} Hydrogen Deuterium Nitrogen Oxygen

solid targets 2%, 5%, 50%, 100% neutrino factory, MiniBooNE, K2K

cryogenic targetsatmospheric neutrino flux

MiniBooNE – HARP ProjectL. Coney, G. Mills, D. Schmitz, M. Sorel, R. Stefanski

● 1994 Began development of a FNAL Booster neutrino beam design and GEANT3 simulation code

● 1997 MiniBooNE/Booster beam proposal, with the realization that /K cross sections were poorly understood (GEANT3/FLUKA)

● 2000 First discussions with HARP people on target calibration (Neutrino 2000, Sudbury, ON)

● 2001-2 GEANT/MARS code and new GEANT4 simulation code

● August 2002 Recorded >20 million 8.9 GeV proton triggers on several replica beryllium target configurations at the HARP experiment

A little history…

The MiniBooNE Neutrino Beam

• Studies show that the largest uncertainty in the flux prediction is the knowledge of the /K production cross sections

• Different models show up to a factor of 2-3 difference in neutrino rates in MiniBooNE!!

It is vital to calibrate the target in a proton beam

e?

MiniBooNE Flux

source of

source of e background

source of e background

source of e background

8 GeV p+

K+

Be

K+ 0 + e+ + e

K0L - + e+ + e

e+ + + e

+ + +

Enter HARP…

• PS214 at CERN (HARP) was designed to measure meson production over nearly 4 solid angle from 1.5 GeV/c to 24 GeV/c across a range of materials (H, D, Be, C, O, N, Al, Sn, Ta, Pb)

• At Neutrino 2000, MiniBooNE was approached by HARP and asked if MiniBooNE would like to us their apparatus

• October 2001: First run with 2% Be target at 8GeV/c

• August 2002 : MiniBooNE replica targets record >20 million triggers (5% , 50% , 100% )

MiniBooNE & HARP

• 1.3M events recorded in 2001 for 8 GeV protons on a 2% Be target• In August, 2002, data was taken for a 5%, 50%, and 100% Be target

71.12 cm = 1.72

2% 5% 50%

MiniBooNE Target

Close-up of HARP Target Region

MiniBooNE Target

MiniBooNE replica targets:

GEANT4 geometry of Replica target:

Running conditions:

• Beam size : x,y RMS < 3 mm (target core diameter 9.5 mm)

• 1000-8000 particles/spill

• 500-1000 events/spill (TPC readout

• Spills at 0.5-1 Hz depending on PS operations

•Data taking over a period of 7 days

•In general, the system was stable, except one period of TPC problems

MiniBooNE Data Taking 2002Target # of Events Comments

5% 6.77 MEmpty thin target holder

0.58 M

50% 5.32 M

Empty 0.50 M Empty thick target holder

2.97 M Entire detector functional and in DAQ

100% 3.71 M (0.78 M)

TPC out of DAQ or having problems

MiniBooNE Target

Target as seen by the beam

Events with an interaction divided by the beam profile (gaussian beam with of 3mm)

You can see where the beam is interacting in the target region.

Target fins

Data Analysis:

● Reconstruction and calibration code under development (HARP collaboration)

● We are helping with the GEANT4 simulation and reconstruction code (Kalman filter for forward spectrometer)

MiniBooNErs at HARP in Action

Dave and Michel

End of talk

Beam Profile on MiniBooNE Target

lepton

leptonifi

i

i

lepii

selectionobsleptonleptoni

fstatesfinal ispeciesneutrinoett

obs

obs

dE

EEd

dE

dNEEEERdEdE

NdE

dN

ett ,,),(

,

arg

arg

Hadron production cross sections, why do we care?

Calculation requiring fluxWant to measure this…

i

imm

mmesonsprotonsi

i

dE

EpdP

dp

dpdN

dE

dNi

tunneldecayhorn

),(,

3

33

Flux calculation:

Known very poorly!MC calculation

MiniBooNE and HARP

Production Rates

Decay Now Goal

K+ 0 + e+ + e

K0L - + e+ + e

~50% 5%

~50% 5%

~100% 10%

~100% 10%

+ e+ + + e

+ + +

Run Summary:

run date time duration spills events setting commentsPeriod 1 17773 8/16/2002 18:29:00 2029 241 90493 693 5% beryllium targetthru 17903 8/19/2002 16:03:29 4493 267 95762 695

Period total 6767478

Period 2 17898 8/19/2002 8:41:00 5472 326 102594 695 Empty thin target holderthru 17881 8/18/2002 21:02:33 2346 280 95762 695 17945-17947 :

Period total 584489 5000-20000 events/spill

Period 3 17915 8/19/2002 21:01:29 1477 175 91207 698 50% MiniBooNE targetthru 17981 8/21/2002 8:09:14 4158 238 98938 698

Period total 5322612

Period 4 17982 8/21/2002 9:32:46 4084 243 99414 700 Empty target holderthru 17986 8/21/2002 14:13:47 4178 248 98443 700

Period total 495451

Period 5 18000 8/21/2002 18:08:45 2506 258 91225 700 100% lamda targetthru 18017 8/22/2002 7:33:41 1480 176 141000 700 TPC PROBLEM runs

Period total 780895

Period 6 18010 8/22/2002 0:20:09 3879 462 333573 700 100% lamda targetthru 18009 8/22/2002 0:04:01 621 73 32380 700 TPC OUT OF DAQ runs

Period total 2431732

Period 7 18021 8/22/2002 9:06:48 4721 278 97419 700 TPC in data with 100% targetthru 18054 8/23/2002 8:33:07 4003 301 69020 701 Thick trigger instead of

Period total 2970808 BEAM trigger at run 18029

Period 8 18055 8/23/2002 9:42:25 7375 468 329047 701 TPC OUT DATAthru 18056 8/23/2002 11:45:44 3545 211 172163 701

Period total 501210