Rezo Shanidze

Rezo Shanidze

KM3NeT sensitivity to neutrino bursts from galactic supernovae

VLVnT08 - Toulon, Var, France 22-24 April 2008

R.Shanidze, VLVnT08 - Toulon, var, France, 22-34 April, 2008

Introduction

Is a -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- 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 www.aspera-eu.org


Neutrinos from the core collapse

The neutrino luminosity (L) vs. time. Calculations of Myra&Burrows for 13 Mʘ progenitor star and 1.17 Mʘ iron core

A. Burrows, Annu. Rev. Nucl. Part. Sci, 40 (1990), 181

The time integrated neutrino number spectra vs. -energy


SN neutrino interactions

The neutrino interaction cross-sections on the different targets vs. energy. From A.Burrows, D.Klein, R.Gandhi, PR D45(1992), 3361

e + p n+ e+ (1) e + 37Cl 37Ar + e(4)e + e e + e- (2) e + 16O 16F + e (5)+e+e3e + 16O 16N + e+(6) l16O 16O* +l(7)


Neutrinos from SN1987A

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

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

Exp. -Events T(sec.) E (MeV) K-II: 12 13 7.5 - 36 IMB: 8 6 20 - 40 Baksan: 5 9 12 - 23


The SN Early Warning System

http://snews.bnl.gov/

The SN prompt alert International network of -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.

Expected SN rate in our Galaxy ~1-3 / century Important not to miss !

Technical description of the SNEWS: New J. Phys. 6(2004),114 [ astrpo-ph/0406214]

The goal of SNEWS is to provide the astronomical community with a prompt alert of the occurrence of a Galactic core collapse event.


The SN neutrinos in a neutrino telescope

First suggested for AMANDA: F. Halzen, J. E. Jacobsen and E. Zas Phys. Rev. D49(1994), 1758 , Ultratransparent Antarctic ice as a supernova detector

11 - events in Kamiokande-II 2.14kton – target mass of Kamiokande-II 52 kpc - distance to SN1987A

Predicted excess of N(p.e.) in a with NOM (10s):

SN1987Asignal in K-II

J. Ahrens et al., (AMANDA Collaboaration),

Astropart. Phys. 16(2002), 345

302 OMs, 215 day (1997-1998)


IceCube sensitivity to the Galactic supernovae

AMANDA-II

AMANDA-B10

IceCube30 kpc

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)

IceCube is sensitive to SN1987A type neutrino burst signal from a distance dSN < 30 kpc. (For 6signal)


Supernova neutrinos in the undersea telescopes

The main difference from other water/ice Cherenkov detectors: a complex sea environment - 40K, bioluminescence, currents, …

3D virtual picture F.Montanet, CNRS/IN2P3 for Antares

ANTARES data: From Dec.2007 data taking with 10 lines (from 12). Constant monitoring of the deep sea environment.

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)


ANTARES environmental data

Constant on-line monitoring of the sea environment is ANTARES:

The values of current mean speed/ direction recorded in ANTARES.


Studies for the ANTARES telescope

[1]S. Basa, ANTARES-PHYS-1998-03 [2] Y. Becherini, G. Ramadori, M. Spurio, ANTARES-PHYS-2002-002 - GEANT 3 simulation of the cherenkov photons produced from positrons in the inverse beta reaction from of the electron anti-. 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 limit for t< 1 s• negligible signal from electron neutrinos

25 ms

10 s

1, 2, 3 - p.e. signal; 4,5 – C2 coincidence

100ms


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: 3” Photonis XP53X2 ( for Multi-PMT (Flykt) OM ) 4) X-HPD based OM

432

The “reference detector”: 8325 Multi-PMT OM (15 x 15 x 37)


Possible SN signal in the KM3NeT telescope

Constant background from the K40 decays: ~ 100 Hz cm-2/PMT~ 40 kHz for 10” PMT/OM (ANTARES) ~ 80 kHzfor Flykt-OM (21x0.09 = 1,8OMANTARES)

The S=N/ 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” (

ANTARES KM3NeT

900 OM (10” PMT) 8325 OM (21 x 3” PMT)

The KM3NeT detector performance evaluated for the reference detector.

Time [ sec.]

0.025

0.050

0.1

0.5

10.020.0

5 significance: < 1 event/ week

S=

N/

ratio

KM3NeT

ANTARES


Possible improvements

Time evolution of the SN signal (N/ratio): For example 2 trigger windows t1 and t2 and a correlation from the time evolution of the SN signal can significantly increase the sensitivity of KM3NeT to the -bursts from the Galactic supernovae.

t1 t2 OM with new PMTs ~ 1.7 x QE


ANTRES/ KM3NeT data model

All data to shore concept:

M. de Jong, KM3NeT CDR meeting.

Fast front-end electronics High bandwidth Software Trigger

“Supernova online trigger” can be implemented on a “on-shore” data, which could run in parallel to other triggers: - 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.


Summary and Outlook

• First study indicates, that the KM3NeT neutrino telescope can detect a supernova neutrino burst as a significant excess of OM rates ( > 5) 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.

Rezo Shanidze

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