1. KM3NeT sensitivity to neutrino bursts from galactic supernovae
Rezo Shanidze
VLVnT08 - Toulon, Var, France
22-24 April 2008

2. Introduction Is a n-burst from a core collapse of a massive star
(Supernova type-II) in Galaxy
detectable with KM3NeT ?
Layout of the talk:
- Supernova neutrinos
- The SNEWS project
- SN-n in the neutrino
telescopes
- Studies for ANTARES
- Estimations for KM3NeT
- Summary and outlook ?
The “Grand unified” neutrino spectrum
from ASPERA Roadmap (phase I).
Status and Perspectives of Astropartile
Physics in Europe
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

3. Neutrinos from the core collapse
A. Burrows,
Annu. Rev. Nucl. Part. Sci, 40 (1990), 181
The neutrino luminosity (Ln) vs. time.
Calculations of Myra&Burrows for
13 Mʘ progenitor star and Mʘ iron core
The time integrated neutrino
number spectra vs. n-energy
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

4. SN neutrino interactions
ne p g n + e (1) ne + 37Cl g 37Ar + e (4)
ne + e- g ne + e (2) ne + 16O g 16F + e- (5)
nm,t + e- g nm,t + e (3) ne + 16O g 16N + e+ (6)
nl O g 16O* + nl (7)
The neutrino interaction cross-sections on the different targets vs. energy.
From A.Burrows, D.Klein, R.Gandhi, PR D45(1992), 3361
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

5. Neutrinos from SN1987A K-II: K. Hirata et al, PRL 58(1987), 1490
IMB: R. M. Bionta el al, PRL 58(1987), 1494
Baksan: E.N. Alexeyev et al. PL B205(1988), 209
The neutrinos from SN1987A detected by
Kamiokande-II, IMB and Baksan detectors.
23 Feb. 1987, 7:35:35 UT
18 h prior to the first optical sighting
Exp n-Events DT(sec.) E (MeV)
K-II:
IMB:
Baksan:
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

6. The SN Early Warning System
Expected SN rate in our Galaxy ~1-3 / century
Important not to miss !
The goal of SNEWS is to provide the astronomical
community with a prompt alert of the occurrence
of a Galactic core collapse event.
Technical description of the SNEWS:
New J. Phys. 6(2004),114 [ astrpo-ph/ ]
The SN prompt alert g International network of n-experiments:
Super-K, LVD, IceCube/AMANDA
( SNO until 2006)
False alert rate of SNEWS < 1 century:
Minimum acceptable level for 10s coincidence:
2 experiments, each with a false alarm rate ≤1 per week.
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

7. The SN neutrinos in a neutrino telescope
SN1987A
signal in K-II
First suggested for AMANDA:
F. Halzen, J. E. Jacobsen and E. Zas
Phys. Rev. D49(1994), 1758 ,
Ultratransparent Antarctic ice
as a supernova detector
Predicted excess of N(p.e.) in a with NOM (10s):
11 - events in Kamiokande-II
2.14kton – target mass of Kamiokande-II
52 kpc - distance to SN1987A
J. Ahrens et al., (AMANDA Collaboaration),
Astropart. Phys. 16(2002), 345
302 OMs, 215 day ( )
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

8. IceCube sensitivity to the Galactic supernovae
AMANDA-II
AMANDA-B10
IceCube
30 kpc
IceCube is sensitive to SN1987A type
neutrino burst signal from a distance
dSN < 30 kpc. (For 6s signal)
Number of the fake SN alerts in IceCube < 15 y-1
The distribution of progenitor stars in the Milky
Way, located within a distance r(kpc) from the
Earth. ( Astropart. Phys.,16(2002), 345)
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

9. Supernova neutrinos in the undersea telescopes
The main difference from
other water/ice Cherenkov
detectors:
a complex sea environment -
40K, bioluminescence, currents, …
ANTARES data:
From Dec.2007 data taking
with 10 lines (from 12).
Constant monitoring of the
deep sea environment.
3D virtual picture
F.Montanet, CNRS/IN2P3 for Antares
The sources of “environmental photons” in ANTARES:
Steady, isotropic radiation from radioactive potassium 40K :~ 350 photons/cm2s.
Continuous bioluminescence ( from bacteria)
Localized bioluminescence bursts ( connected to the macroscopic organisms)
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

10. ANTARES environmental data
Constant on-line monitoring of the sea environment is ANTARES:
The values of current mean speed/ direction
recorded in ANTARES.
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

11. Studies for the ANTARES telescope
[1] S. Basa, ANTARES-PHYS
[2] Y. Becherini, G. Ramadori, M. Spurio, ANTARES-PHYS
- GEANT 3 simulation of the cherenkov photons produced from positrons
in the inverse beta reaction from of the electron anti-n.
ANTARES configuration [2]: 900 OM/PMTs (10 line detector)
Different signals studied : 1, 2, 3 p.e hit rates, coincidence rates (c2)
SN (SN1987A type)
at D=10 kpc (GC)
Maximal sensitivity for
1 p.e. signals
Above 3 s limit for
Dt< 1 s
negligible signal from
electron neutrinos
25 ms
100ms
10 s
1, 2, 3 - p.e. signal; 4,5 – C2 coincidence
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

12. The KM3NeT configuration
For SN study: KM3NeT is a collection of OMs/PMTs.
CDR options:
1) Standard: 10” Hamamatsu R7081
2) Directional 10” OM
3) Small: ” Photonis XP53X2 ( for Multi-PMT (Flykt) OM )
4) X-HPD based OM 4 3 2
The “reference detector”: Multi-PMT OM (15 x 15 x 37)
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

13. Possible SN signal in the KM3NeT telescope
The KM3NeT detector performance evaluated for the reference detector.
ANTARES g KM3NeT
5 s significance:
< 1 event/ week
900 OM (10” PMT)
8325 OM (21 x 3” PMT)
Constant background from the K40 decays:
~ 100 Hz cm-2/PMT :
~ 40 kHz for 10” PMT/OM (ANTARES)
~ 80 kHz for Flykt-OM (21x0.09 = 1,8OMANTARES)
KM3NeT
0.025
S=N/s ratio
0.050
0.5
The S=N/s ratio for ANTARES and
KM3NeT vs time. in sec.
KM3NeT data is obtained by rescaling
the number of OMs:
1) Same type of OM (▪)
2) “Flykt-OM” ()
0.1
10.0
20.0
ANTARES
Time [ sec.]
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

14. Possible improvements
Time evolution of the SN signal (N/s ratio):
For example 2 trigger windows Dt1 and Dt2 and a correlation from the
time evolution of the SN signal can significantly increase the sensitivity
of KM3NeT to the n-bursts from the Galactic supernovae.
Dt1
Dt2
OM with
new PMTs
~ 1.7 x QE
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

15. ANTRES/ KM3NeT data model
All data to shore concept:
Fast front-end electronics
High bandwidth
Software Trigger
M. de Jong, KM3NeT CDR meeting.
“Supernova online trigger”
can be implemented on a
“on-shore” data, which
could run in parallel to
other triggers:
m - trigger
GC - trigger
GRB - trigger
GRB trigger: All ANTARES hits (L0) detected in 120s are stored on
a disk for GCN alert (~ 23 GB/trigger )
Same date can be used for “SN trigger” study in ANTARES.
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008

16. Summary and Outlook
First study indicates, that the KM3NeT neutrino telescope can
detect a supernova neutrino burst as a significant excess of OM
rates ( > 5s) in a short time interval (~10 s) , for a SN1987A type
supernova explosion at a distance < 10 kpc.
Constant monitoring of the sea environment will be necessary to keep
a “false supernova trigger” rate below a level acceptable by the
SNEWS network ( ≤ 1/week).
After the selection of KM3NeT neutrino telescope configuration,
the optical modules and the site, sensitivity to the neutrino bursts
from the supernovae can be studied with dedicated MC (GEANT4)
simulations.
The “ supernova neutrino trigger” can be designed and tested for
the ANTARES neutrino telescope, with an aim of providing the rate
below 1 trigger/week.
R.Shanidze, VLVnT08 - Toulon, var, France, April, 2008