1 / 20

Study of neutrino-electron scattering with CsI(Tl) crystal array at Kuo-Sheng Reactor Laboratory

This study presents the analysis of neutrino-electron scattering using a CsI(Tl) crystal array at Kuo-Sheng Reactor Laboratory. It covers the physics of neutrino-electron interaction, the configuration of the CsI(Tl) detector, and data analysis techniques.

sdavila
Télécharger la présentation

Study of neutrino-electron scattering with CsI(Tl) crystal array at Kuo-Sheng Reactor Laboratory

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. Study of neutrino-electron scattering with CsI(Tl) crystal array at Kuo-Sheng Reactor Laboratory Lin Shin-Ted (On behalf of the TEXONO Collaboration)Academia Sinica, Taiwan @NSYSU Feb. 2005 • Physics with neutrino-electron interaction • Period -II configuration on CsI(Tl) detector • Data Analysis Techniques ※ Cuts ※ Cut summary • Background Understanding (ZYF’s input) • Results (Prelim.) Taiwan EXperiement On NeutrinO http://hepmail.phys.sinica.edu.tw/~texono/

  2. g g g For (ne-e), both NC & CC and their interference term contribute

  3. Reactor Neutrino Interaction Cross-Sections Reactor : high flux of low (MeV range) energy ne On-Going Data Taking:4SM s (ne) 4T > 3 MeV R&D:4Coh. (nN) 4T< 1 keV Results & More Data:4mn (ne) 4T~ 1-100 keV

  4. Kuo-Sheng Reactor Neutrino Laboratory Front Gate Front View (cosmic vetos, shieldings, control room …..) Configuration: Modest yet Unique Flexible Design: Allows different detectors conf. for different physics Inner Target Volume

  5. Period-2 CsI(Tl) Array : 186 kg, 93 crystals Period II : Jan.28, 2003 – Jan.08 2004 ( ~ 50 days OFF 130 days ON) Single Crystal QL Vs QR (Raw Data) Z = 0 cm Z =40 cm 208Tl 40K 137Cs Region of Interest for SMs(ne)

  6. CsI(Tl) Array : Highlights • 40 cm length; 186 kg mass (longest commercial prod.) • Energy+3D info: 10% FWHM @ 660 keV Z-position resolution is 2 cm @ 660 keV s(z) <2 cm @ E>250 keV • Detector Threshold 3 MeV • Range of O (0.0407 cpd) [counts/kg/day] > 3 MeV background • PSD for g/a : > 99% Data Volume : Total > 250 / 50 days ON/OFF • Goals: • Commission 500kg target on-site • DAQ with large dynamic range

  7. Data Analysis Techniques No Cut: Energy Spectrum Defining Cuts: 1] General Cuts –a) No Cut energy spectrumb) Single Event Hit & Single Crystal Hit c) Cosmic ray Cut d) Rough Z-pos. cut SEH, SCH SEH, & SCH SEH, SCH, & Cosmic SEH, SCH, Cosmic-ray, & Z-pos SEH, SCH SEH, SCH SEH, SCH

  8. Data Analysis Techniques Defining Cuts:2] Special Cuts – a) Alpha Event Cut(having fast decay time) Check-Alphas are located around 2 MeV Select-event having Time average less than 40 [Nucl. Instrum. Methods A 523, 116 (2004)] Normal Event Pulse Alpha Event Pulse A; .

  9. Data Analysis Techniques Defining Cuts:3] Special Cuts – a) Double Event Cut(Left side double pulse) b – a pulse ! • 232Th series: • 212Bi(β-, 60.6min, 64%) → 212Po(α, 304ns) → 208Pb

  10. Data Analysis Techniques Defining Cuts:4] Special Cuts – a) Double Event Cut(Right side Double Pulse)

  11. Data Analysis Techniques 40cm long crystal No cut Defining Cuts:3] Z-position Cut – Select – Both side peak mean initially taken as 0 & 40 ! 0 cm 40 cm Narrow Pulse Normal Pulse AlphaPulse

  12. Cut Summary Cut Type All energy Above 3 MeVEfficiency (Suppression) (Suppression) [1] Raw data 1.00 1.00 1.00[2] Cosmic ray 0.11 0.88 0.93[3] anti-Compton 0.70 0.86 0.99[4] Single Trigger 0.01 0.02 0.99[5] Alpha 0.10 0.83 1.00[6] Double Pulse 0.11 0.38 0.99 (Left side & Right side) * Z-position cut is not applied !!

  13. Period-II CsI(Tl) Array : Results (Prilim.) OFF/ON DATA Energy Spectrum of recoil electron 137Cs (661 keV) 137Cs (661 keV) 40K (1461 keV) 40K (1461 keV) 208Tl (2615 keV) 208Tl (2615 keV)

  14. Background Understanding Prospects:- • Estimate the abundance of 238U and 232Th • Figure out the contribution of the two chains to the spectrum of the background

  15. 232Th Decay chain • α- α events Selection: • Simply choose α events and inspect the time interval between two adjacent ones • Cuts:Cosmic ray veto, Single hit, delay time<1s 220Rn --(55.6 s Ea=6.405MeV)-> 216Po--(0.145 s Ea=6.907MeV-> 212Pb • Results: • Delaytime • T1/2=0.153 sec. • Energy: • 6.405MeV: 3424.1KeV • QF: 1.87 • 6.907MeV: 3775.2KeV • QF: 1.83

  16. Background Understanding • From tagging event by event beta-alpha rate 0.43/day/kg alpha-alpha rate 0.71 /day/kg • Results: Above 3 MeV 0.0043 /day/kg Above 3.5 MeV 0.0042 /day/kg - delayed coincidence

  17. Results (Prilim.) OFF DATA(~3000 kg.days) Energy Spectrum of recoil electron 137Cs (661 keV) Above 3 MeV Counts/day/kg = 0.0116 (SM) Counts/day/kg = 0.0318 Above 3.5 MeV Counts/day/kg = 0.00574 (SM) Counts/day/kg = 0.00617 40K (1461 keV) 208Tl (2615 keV) 4 cm zpos (both side) cut !! * 42 Crystals (40 cm.) * Mass 67.2 kg * Data set 46 days OFF period

  18. Period-IICsI(Tl) Array : Results (Prelim.) The Estimate of BKG Suppression >3 MeV * Cosmic ~ one order * From Veto to All Cuts> Two order * 80kg All Cuts to ON-OFF ~ One order * S/B ratio (integral > 3 MeV) = 1/ 2.8 (->2.4) * D = (ds/s) = 40 %~ 2.3s measurement ! 10500 kg-days ON-period3200 kg-days OFF-period Differential Event Count for CsI(Tl)

  19. World status ! General conclusion is that a 1% measurement is well-worth pursuing ! “There is NOT YET any real measurement of reactor neutrino expt”. TEXONO NuTeV Qw(Cs) Czarnecki & Marciano (2000) E158 Run I+II (Preliminary) PDG2002 Measurements of sin2qw as a function of Q. The curve shows the Standard Model expectation

  20. World status ! Characteristics of the previous and current neutrino-e scattering experiments Expected Sensitivities : The accuracy of s(nee) drop down to 20% “Sin2qW was observed but there is NOT YET any real measurement for reactor neutrino”.

More Related