The CRTNT Project

1
TeVPA08
The CRTNT Project (Cosmic Ray Tau Neutrino
Telescope) --- sensitivity and prototype
experiment Huihai He, IHEP, CAS On behalf of the
CRTNT collaboration
2
Outline

• Introduction
• CRTNT sensitivity to AGN neutrinos
• Two prototype telescopes _at_YBJ
• Summary

3
(No Transcript)
4
AGN?? burst?GZK, TD, Z-burst
UHE ? µ
?e
?t
Oscillation
Fluorecsence Cerenkov light
Air Shower
x16
F/C light telescopes
3m
2.5m
5
The CRTNT project
4 stations, each has 4 telescopes, covering
14??64? field of view. Site Balikun, Xinjiang,
China Energy range E gt 100TeV for neutrino,
E gt 0.1EeV for UHECR.
UHECR
Mountain-passing ?? event
Earth-skimming ?? event
6
Physics Topics

• Traditional Physics Topics
• Diffusive flux from AGN, GRB and GZK
• Galactic Sources
• Pulsar may contribute VHE-? flux, just next to
  diffuse AGN flux. However, Near-by galactic
  pulsar may be strong point source! (L.Zhang,
  2006)
• SWIFT near-by (Zlt0.033) GRBs 500x more than
  predicted, neutrinos are more energetic
• (N.GuptaB.Zhang, 2006)
• Cosmogenic neutrinos with IR background
• (T.Stanev on CRIS, 2006)
• New Physics beyond SM

7
Monte Carlo simulation

• Neutrino simulation (Mt. Balikun)
• Shower simulation
• Corsika shower lib
• Photon production propagation (Direct Cerenkov,
  Fluorescence, Aerosol scattering, Rayleigh
  scattering)
• Sky light background (40/m2/µs from measurement)
• Detectorelectronics
• Cosmic ray background

8
Baliikun topograph detector configuration
y
S
FOV (6214.5) zenith angle 83.5
(30., 2.)
x
(15., -2.)
(-5., -2. )
(5., -3.)
9
Neutrino energy spectrum
D. V. Semikoz, G. Sigl, JCAP 0404003, 2004
(hep-ph/0309328)
10
Neutrino event rate

• R event rate (per year)
• N number of primary neutrino per year
• contain CRTNT acceptance (area ? solid angle
  cm2 sr ) and neutrino fluxcm-2 s-1 sr-1
• - ? neutrino conversion efficiency (1.9210-4)
• -? trigger efficiency (21.8)
• D duty cycle (15)
• R 35.7/year
• (totally 108 neutrinos simulated)

11
Cosmic rays as background---efficiency 2.54,
30,000/year
12
Cerenkov (17.7)
horizontal (7.9)
very long(7.2)
Neutrino Event Selection Before Reconstruction ef
f 80, 30/year 0.4 CRs
up-going (41.5)
back-to mountain(5.8)
13
CRTNT sensitivity
Feldman-Cousin method for upper limits (PRD, 2008
) Assume F(En) F0 En-2 90 C.L.

• 1 ANTARES (1 year)
• 2 AMANDA-II
• (2000-2003, 807 days)
• 3 CRTNT (1 year)
• 4 CRTNT (3 years)
• 5 IceCube (3 years)

14
(No Transcript)
15
1
Camera 256 PMTs Electronics on backboard
Telescope housing trailer
CRTNT
Online calibration sys.
5m2 spherical reflector power supplies
16
Data history

• FADC 50MHz?20ns
• Narrow signals are shaped to gt3 FADC bins
• 300 bins/history
• 3 histories/event
• two 10-bits FADCs (high/low gain)/PMT
• ?3.5 orders of dynamic range
• Trigger threshold online adjustable

17
Trigger Algorithm

• Trigger pattern
• Cerenkov round
• Fluorescence line
• Trigger mode
• mono?local
• Stereo?global

18
Relative gain calib. with LED (each day)
YBJ Sky background Star trajectory-pointing calib
(lt0.3 deg.) Test on DC coupling PMT
responses Stability of telescopes during hours of
operation
19
(No Transcript)
20
Basic distributions
21
Offline coincidence with ARGO

• GPS timing lt100ns
• Coincidence efficiency 80

ARGO
CRTNT
22
Offline coincidence with ARGO
Energy threshold10TeV
23
Summary

• CRTNT is complimentary to underground neutrino
  detectors watching the southern hemisphere
• 30 AGN neutrinos can be detected by CRTNT vs.
  0.4 CRs per year,
• Upper limits (90 C.L.) 6.7 (eV.s-1.sr-1.cm-2)
  in three years
• CRTNT is as effective as IceCube with much lower
  cost.
• 2 prototype telescopes are completed and tested
  at YBJ, Tibet.
• CRs are observed coincident with ARGO-YBJ RPC
  carpet array
• Study of cosmic ray spectrum in the Knee region
  with the prototype telescopes is undergoing
• Scan for cosmic ray background as a function of
  elevation

24
Acknowledgements

• We are very grateful to the ARGO-YBJ
  Collaboration for the authorization to use the
  data of the ARGO-YBJ experiment

Thanks!
25
(No Transcript)
26
Optimal thickness
Lm 80 m
Lm 625 m
Lm 4.5 km
Lm 30 km

• Most of the effective interaction occur within
  few decay length inside mountain.

Lm 150 m
27
Maximum efficiency

• Maximum ???? efficiency
• ??? ??
• ? P??? ? ??/??
• ?? ?1/??N ? E-0.37
• ?? ? E
• ? P??? ? E1.37

28
Total photon-electrons

• The total photon-electrons are

29
Cosmic Ray Background3x104CRs/yr (70o75o)
CR Zenith angle
CR Energy
? Energy
? Zenith angle
30
Neutrino Interaction

• NC?N??N
• CC?N? l N

CC
CC
CC
1
CC
NC
Regeneration 1
CC
CC
tau loss 1
CC
CC
31
? interaction cross-section

• 1/?? NA ? ??N
• ??? neutrino current cross-section,
• ?? N ? ? X
• ? rock density 2.65 g/cm3
• ?? ? c T?
• ? (E? /1015 eV) 49.02 m
• E? (1-y) E? where y is fraction of energy carry
  out by interacting nucleon, ?y??¼, So E? ? ¾ E?

32

• Tau energy loss
  

(1) Bremsstrahlung
(2) Pair production
(3) Photonuclear interactions
(4) Ionization
33
Tau Decay
17.8 17.7
34
Sharada et al., hep-ph/050428
35
P??? Conversion efficiency in mountain
Blue No dE/dX Red w. dE/dX