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Status of the HARP Experiment

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  1. Status of the HARP Experiment Chris Booth University of Sheffield HARP Status – Chris Booth

  2. Outline • Motivation • Neutrino Physics • Muon storage ring design • Requirements and Design • Acceptance • Particle identification • History and Status • Results from the technical run • Current status HARP Status – Chris Booth

  3. Motivation – Neutrino Physics! Neutrino physics – first indication of physics beyond S.M. • Solar neutrinos • Atmospheric neutrinos • Neutrino beams (LSND, ….) Conventional accelerator  beams p N  + X  +   e+ e  K+ X  + e+ e Mixture of species, , e Range of momenta of progenitors Uncertain fluxes HARP Status – Chris Booth

  4. Motivation – reduced  systematics E.g. Atmospheric neutrinos: 30% uncertainty in fluxes 7% uncertainty in ratio  / e  Dedicated neutrino beams, from monoenergetic muons. Aims of HARP • Optimal design of target and collector for  source • Calculation of atmospheric  fluxes • Calibration of  beams for K2K and MiniBooNe • Stopped  source for solid state physics HARP Status – Chris Booth

  5. Targetry for Neutrino Factory • Proposal to build a muon storage ring for a -factory. • (also first stage of a high energy-collider) • High -fluxes are required for precision measurements • ~1012 m–2yr–1 for 732 km baseline or ~1010 m–2yr–1 for 7332 km • Requires ~1021 muons per year • Requires ~1021 pions per year • This assumes capturing ~0.6 pions/incident proton • Need high Z target • +/– ratio should be ~1 requires low A • Several proton driver designs • CERN: Linac+accumulator p=2 GeV/c • FNAL: Synchrotron p=16 GeV/c • CERN-BNL:Synchrotron p=24 GeV/c HARP Status – Chris Booth

  6. HARP: hadronic ds/dPT/dPL at various beam energy and targets HARP Status – Chris Booth

  7. Targets and pion capture • Two parameters are important: • pTmax determined by inner radius of the capture solenoid • Acceptance of the RF-system given by pL spectrum of pions • To optimise the target and capture system requires good knowledge of the pT and pL spectra to very low pT values. HARP Status – Chris Booth

  8. Low Energy pion production Observe pions and protons HARP Status – Chris Booth

  9. Surely it has all been done before ! • Lack of data!! • few old experiments: • Allaby et al.(1970) • Eichten et al.(1972) 24 GeV p Be • small acceptances • in many cases only Be target with beam energies in the range 12-24 GeV Xlab =p/pbeam HARP Status – Chris Booth

  10. Data required for a -Factory We can optimize the neutrino factory design by: 1. maximizing the p+ p– production rate /proton /GeV 2. knowing with high precision (<5%) the PT distribution BUT the current simulation packages (FLUKA and MARS) show a 30%-100% discrepancies on pion yields HARP Status – Chris Booth

  11. HARP experiment PS214 Università degli Studi e Sezione INFN, Bari, Italy 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 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 Rutherford Appleton Laboratory, Chilton, Didcot, UK Dept. of Physics and Astronomy, University of Sheffield, UK Faculty of Physics, St Kliment Ohridski University, Sofia, Bulgaria Università di Trieste e Sezione INFN, Trieste, Italy Univ. de Valencia, Spain 22 institutes 107 authors HARP Status – Chris Booth

  12. HARP will measure...... • Hadronic production cross sections (d/dPT,dPL) at various energies and with various targets • Goal: 2% accuracy over all phase space O(106) events/setting, low systematic error CERN PS, T9 beam, 2 GeV/c – 15 GeV/c Approval: December 1999 • "Stage 0" Technical run with partial set-up, 25 September – 25 October 2000 • Stage 1 Measurements with solid and cryogenic targets, 2001 + early 2002 • Future plans: Measurements with incoming Deuterium and Helium, 2002 ~100 GeV incoming beam, using NA49 set-up HARP Status – Chris Booth

  13. Recycling! Very short timescale  re-use existing equipment & designs • DC & TOF wall from NOMAD • prototype TPC from ALEPH • dipole magnet from Orsay • Electron-identifier from CHORUS • … However, in practice many changes, re-optimisations etc required, so most has had to be rebuilt! HARP Status – Chris Booth

  14. Deliverables Input data for the design of the Neutrino factory/Muon collider Input data for the Atmospheric neutrino flux calculations Precise predictions of the neutrino fluxes for the K2K and MiniBooNE experiments targets will be installed in HARP Input data for the hadron generators in Monte Carlo simulation packages GEANT-4 HARP Status – Chris Booth

  15. Parameters to optimise: proton energy, target material and target geometry, D2 CERN: Linac 2 GeV BNL: Synch. 24 GeV FNAL: Synch. 16 GeV • Proton beam 2-24 GeV • Li,Be,C,Al,Cu,liq.Hg etc. • (thin and thick) Various high-Z Targets p+/p- ratio: • D2 beam backward-going pions • stopped muon source We Need new DATA HARP Status – Chris Booth

  16. Acceptance and particle-ID Momentum evaluation over 2 decades (100 MeV–10 GeV) Large acceptance (even backward) p/p separation K/p separation electron/p separation HARP Status – Chris Booth

  17. Acceptance and particle-ID • Acceptance • Target inside TPC • Forward spectrometer (drift chambers) • Identification • Time of flight (RPCs & scintillators) • dE/dx (TPC) • Cherenkov • e &  identifiers (scintillator/absorbers) HARP Status – Chris Booth

  18. Experimental setup particle-id at low pL, low pT TOF wall electron identifier …-id at large pL Cherenkov muon identifier spectrometer magnet forward trigger forward RPC TPC solenoid magnet High pT and particle-id beam drift chambers Tracking, low pT spectrometer HARP Status – Chris Booth

  19. Targets – U.K. responsibility Solid targets > 99.99% pure Cryogenic targets all 6 cm long target tube target holder Special targets HARP Status – Chris Booth

  20. TPC pad plane/readout beam TPC field cage ITC inner trigger cylinder RPC barrel solenoid coil target 2.24 m Experimental setup HARP Status – Chris Booth

  21. HARP beam 1.59 m TPC Field cages HV plane ~ 22 kV “cork” (HV degrading + calibration systems) PAD plane readout metallisation Stesalit wall (8 mm outer, 2 mm inner) HARP Status – Chris Booth

  22. TPC PAD size 6.515 mm2 20 PAD rows 3972 PADs in total "CALICE" preamplifier chips on the back of the PAD plane  flex connection buffer amplifier pico-coax cable (5 m) FEDC (VME card with 10-bit ADC and digital circuit for data reduction) 32 cm Wire planes: anode wires (no field wires) cathode wires gating grid all wiring around precision pins on a 7 mm wide spoke-wheel Gate Wiring scheme gate wiring HARP Status – Chris Booth

  23. TPC Gas choice: 90% Ar, 10% CO2 Gas speed: 5 cm/s Total drift time: 32 s  320 time samples at 10 MHz Expect around 1% of the 1.3106 PAD-time words to contain a hit  data reduction in the FEDC  up to ~50 kBytes per event to be read out for up to 1000 events/spill • TPC calibration systems: • Mn source • Photo-emission from UV light (aluminised optical fibre) • Gate pulsing • Radioactive gas • Cosmics HARP Status – Chris Booth

  24. TPC The TPC design takes into account the results of many detailed simulations/calculations on: gas choice, B-field dependence, ion movements, gating studies, simulation of PAD response function, electrostatics for wire planes and field cage, mechanical deformations Charge sharing With field wires Charge sharing Without field wires HARP Status – Chris Booth

  25. TPC • TPCino prototype • mini-TPC with 24 PADs • final wire configuration • 90% Ar, 10% CO2 • Short drift ~5 cm • "Calice" preamps • Buffer amplifiers • Pico-coax cable • Alice FE Digital Card • DATE DAQ • Monitoring • Laser for photo emission • Allows to test • PAD signals under various conditions • Gating system • Calibration systems • PAD response function • dE/dx resolution TPCino Pad Response Function measured with (point-like) -source and oscilloscope readout HARP Status – Chris Booth

  26. TPC HARP-TPCino Full electronic chain Point-like photo emission source preliminary: pulseheight 10-14% HARP Status – Chris Booth

  27. TPC TPCino test setup, full readout chain, online monitoring scope view of a single PAD 10 MHz readout 200 ns 30 s FWHM of signal duration HARP Status – Chris Booth

  28. RPC Additional detector (not in the proposal) Particle (e–) separation at low momenta (150 MeV – 250 MeV) <200 ps time resolution needed can be achieved with RPC 4 gaps of 0.3 mm thickness module size: 192 cm  10.6 cm PAD size: 10.4 cm  2.95 cm • Barrel-part, around the TPC: 30 RPC modules • Forward part, at the TPC exit: 16 RPC modules • Each PAD is read out by its own (OPA687) preamplifier • 8 PADs are added together after the amplifier stage • Signal split into: trigger, TDC, ADC • Total 368 readout channels HARP Status – Chris Booth

  29. RPC Prototype results (T10 test beam) =104 ps Time (TDC channel 50 ps) (30 ps trigger resolution still folded in) HARP Status – Chris Booth

  30. Solenoid magnet • Ex-ALEPH TPC90 magnet • Magnet Requirements: • Homogeneous field in TPC (1.6 m long) • Br/Bz < 1% • Field strength 0.7 T • Downstream return yoke removed • Needed 50 cm extra length • 20 new coils • of which 14 with a larger radius new coils HARP Status – Chris Booth

  31. BdL 0.68 Tm 1 m August 2000 August 2000 Spectrometer magnet HARP Status – Chris Booth

  32. Spectrometer magnet By (in x,z plane) interpolation of magnetic field measurements By (in y,z plane) HARP Status – Chris Booth

  33. Drift chambers Drift Chambers 32 mm drift length 1 chamber = 1 triplet 1 module = 4 chambers wires at –5º, 0º, +5º total 126 wires/chamber 8 mm gas gap gas: 90%Ar, 9%CO2, 1%CH4 Read out by: CAEN TDC V767 23 chambers installed in HARP (69 planes) HARP Status – Chris Booth

  34. Cherenkov box, 30 m3 filled with C4F10 gas 2 rows of 19 PM's (8") in magnetic shielding additional focusing: Winston cones beam 5.4 m Cherenkov threshold cylindrical mirror, 8 m2 curvature radius 2.4 m HARP Status – Chris Booth

  35. Cherenkov Design • C4F10 threshold mode • 34 Chooz PMs EMI 9356KA • Optimisation of granularity for expected occupancy • PM shielding requirements • Mirrors/focussing design scheme (and technology) • Serious construction problems! Serious leaks! Removed from area and dismantled, to be re-welded. HARP Status – Chris Booth

  36. Cherenkov mirror support Mirror reflectivity 90% 300 nm 700 nm Winston cone PM + shielding HARP Status – Chris Booth

  37. 2.5 m 420 ps 300 ps technical run prototype results: time difference between 2 counters ~7.4 m 280 ps 200 ps Time-Of-Flight wall 39 counters 2.5 cm thick BC408 HARP Status – Chris Booth

  38. Electron and Muon identifier Electron identifier: Pb/fibre: 4/1 62 EM modules, 4 cm thick 80 HAD1 modules, 8 cm thick Muon identifier: Iron + scintillator slabs Thickness 6.44 I electron identifier 3.3 m 6.72 m muon identifier HARP Status – Chris Booth

  39. Trigger system Trigger: internal (sci-fibs) AND external RPCs AND TOF Outer Trigger 24 RPCs (TOF to support the TPC e/h separation) Forward RPCs Inner Fibre Trigger (Backward/Large angle) …and far TOF plane (10 m distance) for small angle particles! HARP Status – Chris Booth

  40. Trigger counters TDS target defining scintillator disc, 2 cm , 5 mm thick, air light guides 4 photomultipliers >99.5 % efficiency per PM ITC inner trigger cylinder surrounding the target 130 cm long, 7 cm  4 layers of 1 mm  scint. fibre viewed by 16 photomultipliers beam trigger interaction trigger HARP Status – Chris Booth

  41. 13/9/2000 6 cm hole for the outgoing beam Trigger counters Forward trigger hodoscope (interaction trigger, together with RPCs) 2 planes of 7 scintillation counters read out from both sides Total coverage 1.4  1.4 m2 at the solenoid exit HARP Status – Chris Booth

  42. Total Acceptance: 15 GeV on Be Forward Spectrometer TPC A 4p experiment!! HARP Status – Chris Booth

  43. p/p separation at 4s level, “conservative” simplification TPC TOF Cherenkov PT-PL box-plot of p distribution from 15 GeV p on Be thin target p/ separation HARP Status – Chris Booth

  44. pions and protons; 2 GeV p on Be pions protons HARP Status – Chris Booth

  45. HARP technical run HARP Status – Chris Booth

  46. A TOF Č Č HARP target B TOF Secondary beam line Horizontal and Vertical Beam diameter (2+2) for the extended T9 beam (simulated, without multiple scattering) Beam particle identification: 2 Cherenkov counters 2 TOF counters (dist. 24 m) HARP Status – Chris Booth

  47. Beam optimization Measured beam sizes ( in mm) 1.28 m in front of HARP focus Multiple scattering effects at low momentum  = 10 mm HARP Status – Chris Booth

  48. C2 (ADC counts) Time difference (ns) Beam particle identification raw data TOFA - TOFB versus Cherenkov-2 1.4 ns nominal (p–+) time difference A complete set of Cherenkov threshold values for all momenta was produced (Calculated + Measured) HARP Status – Chris Booth

  49. Beam chambers • 4 MWPC with 1 mm (2 mm) wire spacing • total ~800 readout channels • Aim: • tracking of incoming beam particles (~105/spill) • monitor beam halo and muon background analog chamber signals (20 mV, 50 ns) Argon ~65% CO2 ~35% New! 50% Ar, 50% C02, trace H2O Lower threshold electronics >99.5% efficiency at lower voltage. HARP Status – Chris Booth

  50. Drift chambers Beam profile, x hits of 1 plane 94% 19 cm -spectrometer on -spectrometer off Drift time  VD47 m/ns ~680 ns Efficiency versus Vanode HARP Status – Chris Booth