H A R P A Hadron Production Experiment at the Proton Synchrotron at CERN
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Transcript of H A R P A Hadron Production Experiment at the Proton Synchrotron at CERN
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 Motivation (general)
Measure absolute inclusive cross-sections for Hadron production with a range of targets and primary proton energies.
HARP Motivation (specific)
● Neutrino Factory Design• Atmospheric Neutrino Flux Calculations• Neutrino Fluxes for MiniBooNE and K2K• Input to Monte Carlo simulation
packages
Neutrino Factory
Æ+ , Æ-
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
MiniBooNE Flux
Æ+ŒÂ+ƒ àsource of
Œ ƒ à Ãee+ source of e background
ŒÆ0ƒ ƒ ÃeK+ e+ source of e background
ŒÆ-ƒ ƒ Ãee+K0L
source of e background
8 GeV p+
K+
Be
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
Time Projection Chamber - TPC
10-1 1 10 p(GeV/c)
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%
+
-
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)
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.
Pion Production and pi/pPID
PT vs. P
L Box Plot for pion Production (@15GeV)
TPCTPC
TOFTOF
CerenkovCerenkov
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 and HARP
Production Rates
Decay Now Goal
Æ+ŒÂ+ƒ ÃÂ
ŒÆ0ƒ ƒ ÃeK+ e+
ŒÆ-ƒ ƒ Ãee+K0L
~50% 5%
~50% 5%
~100% 10%
~100% 10%
e+
Â+Œ ƒ à Ãe
MiniBooNE & HARP
• 1.3M events recorded in 2001 for 8 GeV protons on a 2% Be target• In August, 2002, data will be taken for a 5% and a 50% Be target
71.12 cm = 1.72
2% 5% 50%
MiniBooNE Target
HARP 2002 Data Taking
• Scheduled for 140 days of running in 2002➢28 days for cryogenic targets➢14 days for special targets➢7 days for setup and calibration➢91 days to run all targets and beam energies
• Cross-section measurements at the 1-2% level shouldbe achievable.