1 / 18

SPL neutrino spectra

SPL neutrino spectra. Antoine Cazes Université Claude Bernard Lyon-I December 16 th, 2008. Presentation based on the following paper: Campagne, Cazes : Eur Phys J C45:643-657,2006. Increasing the proton energy:. Positive aspect Increase of the pion cross section Increase of the boost

lawsonk
Download Presentation

SPL neutrino spectra

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. SPL neutrino spectra Antoine Cazes Université Claude Bernard Lyon-I December 16th, 2008 Presentation based on the following paper: Campagne, Cazes : Eur Phys J C45:643-657,2006

  2. Increasing the proton energy: • Positive aspect • Increase of the pion cross section • Increase of the boost • Negative aspect • Increase of the kaon cross section • Decrease the number of pot (normalization to 4MW) • Optimization is a balance between these arguments • Guide line : • (Dm²  2.5 10-3eV²) • CERN-Fréjus = 130km  En 260 MeV  pp 600 MeV/c

  3. Particle Producion p+ K+ p- K0 K- Ep(GeV) Ep(GeV) • 500 000 protons, Ek < 5GeV • at 2.2GeV : • 0.26 p+/s • 0.8 10-3 K+/s • at 4.5GeV : • 0.32 p+/s • 5.2 10-3 K+/s • at 3.5GeV : • 0.29 p+/s • 2.8 10-3 K+/s

  4. p p p n Simulation steps • Target simulation • horn simulation • designs • tracking • Decay tunnel • geometry • decay simulation • Fluxes at Fréjus

  5. Interaction between proton beam and target. • Simulation done with FLUKA 2002.4 and MARS • Proton beam • Pencil like • Ek=2.2GeV, 3.5GeV, 4.5GeV, 6.5GeV and 8GeV • Target • Liquid mercury • Long : 30cm •  15mm • Normalization: 4MW • 1.1×1016pot/s@2.2GeV • 0.7×1016pot/s@3.5GeV • 106 protons on target have been produced

  6. Kinetic energy (GeV) of pions and kaons p+ 1GeV 2GeV K0 K+ 1GeV 2GeV 1GeV 2GeV

  7. 80 cm p 140 cm 220 cm Horn design • Low energy proton beam (3.5 GeV) • Large transverse momentum for the pions • <qp> = 55° • Target must be inside the horn:

  8. p En 300 MeV pp 800 MeV/c B1 B2 Optimisation of the horn design • Set a toroïdal magnetic field • Send a pion from the target, Stop when it is horizontal. • Repeat with different angles • Design your horn ! x With different proton energy, the horn can be design to produce similar neutrino flux

  9. p Horn simulation • Drawing from the horn built at CERN • Using Geant 3.2.1 • Tracking cuts • µ, hadrons : 100 keV • g, e+, e- : 10 keV • Stepping : • 10mrad in the magnetic field • 100µm and loose less than 1% of Ek in the conductors

  10. Length modify purity L=10m, 20m, 40m and 60m have been tested. 10m40m nm , nm + 50% to 70% ne , ne + 50% to 100% 40m60m nm , nm + 5% ne , ne+ 20% 40m seems better Radius modify acceptance R=1m, 1.5m and 2m have been Tested 1m 2m (L=40) nm , nm +50% ne , ne +50% to 70% 2m seems better Decay Tunnel Parameters This results have been checked on sensitivity to q13 and dCP

  11. Flux computation • Low energy  Small boost  low focusing • Need a high number of events (~1015 evts!!!) • Use probability • Each time a pion, a muon, or a kaon is decayed by Geant, compute the probability for the neutrino to reach the detector • Use this probability as a weight, and fill an histogram with the neutrino energy • Gives neutrino spectrum.

  12. nm d q p+ 1 – b2 1 A m+ P = p a 4p (b cosa -1)2 L2 p Probability method …. Pions • Pion is tracked by Geant • When it decays, The probability for the neutrino to reach the detector is computed: • p+m+nm : (2-body decay) L : distance to detector A : detector surface To reach the detector: d = -a

  13. 1 A 2 1 1 – bm2 P =  4p L2 mm 1 + bmcosqm (bmcosr -1)2 * (f0(x) Pf1(x)cosqm)  * Probability method …. Muons • m+e+nmne • But muons have small decay probability. • for each muon • loop on the phase space (q,f,E) • compute decay probability e-x/gct • if it decays, compute probability for the neutrino to reach the detector : x = 2En/mm • P is the muon polarisation coming from the pion/kaon decay

  14. Probability method …. Kaons • Very few kaons : • kaon produced in the target is duplicated many times: ~100. • Decay using Geant • Choose the decay channel • Probability computed depending on the decay channel • 2 body decay • 3 body decay

  15. from p and m from K0 from K Ekine (GeV) Ekine (GeV) evts/100m2/y Ekine (GeV) Ekine (GeV) Ek=3.5GeV En ~300MeV L = 40m,R=2m Neutrino Flux 100km away p+ focusing

  16. Neutrino flux @ 130km • 3.5GeV Kinetic proton beam • ~800MeV p focusing • ~300MeV neutrinos • 40m decay tunnel length • 2m decay tunnel radius • Flux available for Ek=2.2GeV, 3.5GeV, 4.5GeV, 6.5GeV and 8GeV and two type of focalization system.

  17. Dm223 (eV2) En~260MeV 2.2GeV 3.5GeV 4.5GeV 8GeV 10-3 dCP = 0 sin22q13 10-3 Proton beam energy comparizon 5 year positive focussing 10 years mixte focussing (8y + and 2y -) Campagne, Cazes : Eur Phys J C45:643-657,2006

  18. Conclusion • Choice of the beam energy is delicate • Tools exist to do another simulation • Proton interaction on target should be better with new version of fluka • Shape of the horns is crucial. • Technical feasability should be taken into account...

More Related