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H A R P A Hadron Production Experiment at the Proton Synchrotron at CERN. Motivation for the HARP experiment The HARP Detector MiniBooNE and HARP. HARP Institutions. Università degli Studi e Sezione INFN , Bari, Italy Rutherford Appleton Laboratory , Chilton, Didcot, UK
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H A R PA Hadron Production Experiment at the Proton Synchrotron at CERN • Motivation for the HARP experiment • The HARP Detector • MiniBooNE and HARP
HARP Institutions Università degli Studi e Sezione INFN, Bari, Italy Rutherford Appleton Laboratory, Chilton, Didcot, UK Institut für Physik, Universität Dortmund, Germany Joint Institute for Nuclear Research, JINR Dubna, Russia Università degli Studi e Sezione INFN, Ferrara, Italy CERN, Geneva, Switzerland Section de Physique, Université de Genève, Switzerland Laboratori Nazionali di Legnaro dell' INFN, Legnaro, Italy Institut de Physique Nucléaire, UCL, Louvain-la-Neuve, Belgium Università degli Studi e Sezione INFN, Milano, Italy P.N. Lebedev Institute of Physics (FIAN), Russian Academy of Sciences, Moscow, Russia Institute for Nuclear Research, Moscow, Russia Università "Federico II" e Sezione INFN, Napoli, Italy Nuclear and Astrophysics Laboratory, University of Oxford, UK Università degli Studi e Sezione INFN, Padova, Italy LPNHE, Université de Paris VI et VII, Paris, France Institute for High Energy Physics, Protvino, Russia Università "La Sapienza" e Sezione INFN Roma I, Roma, Italy Università degli Studi e Sezione INFN Roma III, Roma, Italy Dept. of Physics, University of Sheffield, UK Faculty of Physics, St Kliment Ohridski University, Sofia, Bulgaria Institute for Nuclear Research and Nuclear Energy, Academy of Sciences, Sofia, Bulgaria Università di Trieste e Sezione INFN, Trieste, Italy Univ. de Valencia, Spain
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/c to 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. p+ , p- 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 choose beam energy (2 -15 GeV). • However, beam consists of different particles - mainly protons and pions. • TOF measurements distinguish different particles in the beam before hitting the HARP target. NOTE: This is different from MiniBooNE. MiniBooNE gets 8 GeV protons directly from the Booster.
HARP detector: Acceptance, PID, Redundancy Threshold gas Cherenkov: p identification at large Pl TOF: p identification in the low Pl and low Pt region Drift Chambers: Tracking and low Pt spectrometer EM filter (beam muon ID and normalization) Target-Trigger 0.7T solenoidal coil Drift Chambers: Tracking TPC, momentum and PID (dE/dX) at large Pt 1.5 T dipole spectrometer
HARP Detector • TPC: • PID • momentum measurement for high pT particles • NDC: • Momentum measurement for low pT forward particles • Cherenkov: • - PID for momentum >3.0 GeV/c • TOF: • - PID primarily for p < 3.0 GeV/c
Time Projection Chamber - TPC • Used for particle id: • p/K up to 0.7 GeV/c • p/p up to 1.2 and above 3 GeV/c • want dE/dx resolution ~6% • And momentum measurement: • r-f resolution of 300 mm • pT resolution dpT/pT=0.033 pT 10-1 1 10 p(GeV/c)
Prototype of the TPC simulation in the GEANT4 framework TPC Hits, ArCO2 Mixture, 0.7T Field, 10 cm C Target
Resistive Plate Chamber -RPC HV + + + ++ + + + ++ Gas Gas + + + ++ + + + ++ HV
Drift Chambers & Spectrometer Magnet • 0.5 T Vertical Field for momentum spectrometry • Vertical, +5°, -5° wire orientation in drift chambers • 90% Argon, 5% CO2, 5% CH4 gas mixture • 150m - 700m resolution depending on incident angle • Typical single chamber efficiency of 97% (~90%) • Current momentum resolution is ~150 MeV at 3GeV + -
Threshold Cerenkov Detector • Filled with C4F10 (perflourobutane) at atmospheric pressure. • Discriminates between protons and pions at high momentum. • At high beam momentum, strange particles (kaons) are also created. C4F10 properties: n = 1.001415 pion threshold = 2.6 GeV/c kaon threshold = 9.3 GeV/c proton threshold = 17.6 GeV/c
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) • - 2s separation up to 4.6 GeV/c for p/p • 2.4 GeV/c for p/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.
p/p separation at 4s level, “conservative” simplification TPC TOF Cherenkov PT vs. PL Box Plot for pion Production on Be (@15GeV)
HARP Targets • Beryllium • Carbon • Aluminum • Copper • Tin • Titanium • Lead } solid targets 2%, 5%, 50%, 100% neutrino factory, MiniBooNE, K2K } • Hydrogen • Deuterium • Nitrogen • Oxygen cryogenic targets atmospheric neutrino flux
MiniBooNE – HARP Project L. Coney, G. Mills, D. Schmitz, M. Sorel, R. Stefanski
A little history… • 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
The MiniBooNE Neutrino Beam nmne? • 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
MiniBooNE Flux + 8 GeV p Be K+ p+gm+ + nm source of g e+ + nm + ne source of e background K+ gp0 + e+ + ne source of e background K0L gp- + e+ + ne source of e background
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 2% 5% 50% MiniBooNE 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 Target Target fins Target as seen by the beam Events with an interaction divided by the beam profile (gaussian beam with s of 3mm) You can see where the beam is interacting in the target region.
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
Hadron production cross sections, why do we care? Calculation requiring flux Want to measure this…
Flux calculation: Known very poorly! MC calculation
MiniBooNE and HARP Production Rates DecayNowGoal p+gm+ + nm ~50% 5% m+g e+ + nm + ne ~50% 5% ~100% 10% K+ gp0 + e+ + ne K0L gp- + e+ + ne ~100% 10%