Piero Galeotti Vulcano 20081

Search for neutrinos from collapsing stars in Italy

(a 30 years report)C. Castagnoli,K. Lande,O. G. Ryazhskaya,O. SaavedraG. T. Zatsepin…..and many others

Atmospheric

Solar

Sources

CNB Supernova

2Piero Galeotti Vulcano 2008

3Piero Galeotti Vulcano 2008

Sun

4Piero Galeotti Vulcano 2008

16041604 ( (KeplerKepler) ) 15721572 ( (TichoTicho))1181118110541054 ( (CrabCrab))10061006

Phase of the collapse

1 2 3

Total neutrino energy(1053 erg)

0,1 1,7 3

Average neutrino energy(MeV)

12 14 15

Time duration (s) 0,04 3,1 151. Formation of the neutrino-sphere.2. Accretion of the envelope on the core.3. Kelvin cooling of the new-born neutron star.

5Piero Galeotti Vulcano 2008

Imshennik, Nadiozhin, Chechetkin, Ivanova, Domogatsky…

Piero Galeotti Astrofisica neutrinica 6cns

B

xx

e

eChC

RGM

RGM

E

n

nHeFe

ee

npe

MYMM

22

456

02

1

413

76.5

Binding energy Binding energy emitted asemitted as99% Neutrinos

of all flavors1% Kinetic energy0.01% Optical luminosity

7Piero Galeotti Vulcano 2008

Raffelt et al.

kT(MeV)

Eth

(MeV) 0,01 0,1t (s)

1 10 > 25

5 0,15 2,55 9,3 24,4 35,3

3 10 0,08 1,33 4,8 12,7 18,3

15 0,02 0,39 1,4 3,7 5,4

20 0,00 0,07 0,3 0,7 1,0

5 0,23 4,0 14,5 38 55

4 10 0,17 3,0 10,9 29 41

15 0,09 1,6 5,7 15 22

20 0,04 0,6 2,2 5,9 8,5

5 0,31 5,3 19 51 73

5 10 0,27 4,6 16,7 44 64

15 0,19 3,2 11,7 31 45

20 0,11 1,8 6,6 17 25 8Piero Galeotti Vulcano 2008

Neutrino ’84, 11th Int. Conf.on Nutrino Physics and Astrophysics

562 563

Main interactions in

scintillator• Inverse β decay:

• Neutrino-elettron scattering:

• Neutral currents interactions:

• Charged currents interactions:

enpe

ee ee ,,,,

*12,,,,

12,,,, )()( CC eeee

eNC

eBC

e

e

1212

1212

22

44

244

cmMeV

109)()(

cmMeV

10)(

Epn

Ee

ee

e

10Piero Galeotti Vulcano 2008

Arteomovsk BST

Soudan

KamiokaGran Sasso

HomestakeMt Blanc

Sudbury

KGF

The muon depth-intensity curve (underground data): curves are calculated by Bugaev et al., 1998

Liquid Scintillator Detector Liquid Scintillator Detector ((LSDLSD))

Fe (2 cm)

Fe (10 cm)

H=5200 m.w.e. 72 counters

90 tons of СnH2n (n~9), 200 tons of Fe

4.5 m

8m

6 m

12Piero Galeotti Vulcano 2008

On line print of five pulses on 23 febbrury 1987 at 3 On line print of five pulses on 23 febbrury 1987 at 3 hr, 52 min, i.t., detected at Mt. Blanc LSD hr, 52 min, i.t., detected at Mt. Blanc LSD

experimentexperiment

Piero Galeotti14

Vulcano 2008

15Piero Galeotti Vulcano 2008

+4

+6

+8

+10

+12

0h 2h52m 7h36m 9h22m 15h54m

Sk – 69o202

McNaught

Radio (21cм)

?

Shelton Jones

DiscoveryJones

Mont Blanc

Kamioka,IMB,

Baksan S W(У В)

1987А

mmvv

UT

Shelton

Feb24 Feb25Feb24 Feb25Piero Galeotti

16Vulcano 2008

Mont Blanc 5 pulses E > 5 MeV UT 2:52:36.8 + 2 msKamioka 11 “ 8 7:35:35 + 1 min

+ (7 pulse at 7:54:22) ? IMB 8 “ 25 7:35:41 + 5 msBST (2+5) “ 10 2:52:34 and 7:36:06 (+ 2s-54s)

DETECTED NEUTRINO SIGNALSDETECTED NEUTRINO SIGNALS

The main signal comes from electron antineutrinos:

ep ne+ followed by e+e_ annihilation producing 2

’s, detectable in scintillator but not in water.The Mont Blanc signal (5.8 < Evis < 7.8 MeV) corresponds to 4.6 < Evis < 6.6 MeV in water, at the limit to be detected in Kamioka.

17Piero Galeotti Vulcano 2008

Kamioka-LSD correlations

0

LSD t = 1.0 ms

Kamioka t= 60 sec

- 60 s + 60 s- 60 s + 60 s

shift

T

NNNc

212

LSD: 91 events, f=0.72/min Eth ≥ 5-7MeV

K-II: 191 events, f=1.4/min Eth ≥ 7.5MeV (20 hits)

T: from 1:45 to 3:45

LSD-KAMIOKANDE Coincidencesin 34 hours- 17-2 hrs intervals – 11.45-22 Feb. – 21.45 - 23 Feb

11.45 17 .45 23.45 5.45 11.45 17.45

2-22 2-23

TIME U.T

2

4

6

8

10

C

t = 0.5 s

Shift = 7.0 s

Shift = 6.9 s1462 events at LSD2890 events at Kamioka

Expected: 2.03

91 Mt. Blanc events240 Baksan events

Annals New YORKAcademy of Sciences,Vol. 571, pag. 577 New York 1989Ed. by Ervin Fenyves

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Coincidences Mt.Blanc-KamiokaCoincidences Mt.Blanc-Kamioka

Coincidence window t = + 0.5 sBin width: 2 hoursCoincidence time: 34 hoursKamioka time + 7 seconds

NC = 191•91•2•0.5/7200 = 2.4NO = 9

Mt. Blanc event time1:45 – 3.45 U.T.

25Piero Galeotti Vulcano 2008

Piero Galeotti, 26

Neutrino interactions in iron

, Fe

e+56Fe 56Co+e-

p

СnH2n

CoeFe e5656

СnH2n

CoeFe e5656

СnH2n

CoeFe e5656

MeVE 72.1

EEE oe

MeVE 82.1 MeVE 72.1

MeVE 4

MeVE 82.1

MeVE 7

e

MeVE 82.1EEE oe EEE oe

e

e

27Piero Galeotti Vulcano 2008

A rotating collapsarA rotating collapsarImshennik Ryazhskaya Collapse Model

12 MM

222 , JM

12 111, JM

~,

e

View from above

View from aside

5 h later

28Piero Galeotti Vulcano 2008

The LVD detector in Gran Sasso 840 scintillator counters, 1.5 m3 each, are inserted in modules holding 8 counters each.The modules are grouped and stacked together to form three towers of 35 modules each.

The scintillator of ach counter (1.2 tons) is watched from the top by 3 PMTs (15 cm diameter).

29Piero Galeotti Vulcano 2008

TopologyTopologySchema numerazione tank del primo piano

1517 1518 1417 1418 1317 1318 1217 1218 1117 1118

1515 1516 1415 1416 1315 1316 1215 1216 1115 1116

1513 1514 1413 1414 1313 1314 1213 1214 1113 1114

1511 1512 1411 1412 1311 1312 1211 1212 1111 1112

2517 2518 2417 2418 2317 2318 2217 2218 2117 2118

2515 2516 2415 2416 2315 2316 2215 2216 2115 2116

2513 2514 2413 2414 2313 2314 2213 2214 2113 2114

2511 2512 2411 2412 2311 2312 2211 2212 2111 2112

3517 3518 3417 3418 3317 3318 3217 3218 3117 3118

3515 3516 3415 3416 3315 3316 3215 3216 3115 3116

3513 3514 3413 3414 3313 3314 3213 3214 3113 3114

3511 3512 3411 3412 3311 3312 3211 3212 3111 3112

INTERNAL Counters (M=570 tons)

FRONT VIEW

EXTERNAL Counters (M=430 tons)

TO

P V

I EW

30Piero Galeotti Vulcano 2008

Neutrino BurstNeutrino BurstDetection in LVDDetection in LVD

interactions in scintillator

e+ p n + e+

i (x ) + e- i (x ) + e-

e+ 12C 12N + e-

e+ 12C 12B + e+

i (x ) +12C i(x ) + + 12C

NC and CC interactions on carbon nuclei useful for neutrino oscillation.

e tagging through detection of delayed from n capture at low energy threshold, efficiency 60%.

-

Piero Galeotti31

Vulcano 2008

LVD 10 LVD 10 yearsyears

High duty cycle (>99.5% since 2002)

Fiducial Active Mass (M~ 900 tons since Jun/2001) 32

Piero Galeotti Vulcano 2008

Active Mass and Duty Cycle

The scintillator stability has been monitored for about 2 years using a 252Cf n-source and periodically measuring:

• n-capture efficiency

• n mean capture time

Both do not show any hint of variation or degradation.

Other measurements are done on smaller samples by directly measuring transmittance and light yield.

n-capture efficiency

mean capture time

stability survey

Piero Galeotti 34Vulcano 2008

RUN Since: To:Uptime[days]

DutyCycle

Mass [tonn]

PUBLISHED

RUN 1 Jun 6th ‘92 May 31st ’93 285 60% 310 23rd ICRC 1993

RUN 2 Aug 4th ‘93 Mar 11th ’95 397 74% 390 24th ICRC 1995

RUN 3 Mar 11th ‘95 Apr 30th ’97 627 90% 400 25th ICRC 1997

RUN 4 Apr 30th ‘97 Mar 15th ‘99 685 94% 415 26th ICRC 1999

RUN 5 Mar 16th ‘99 Dec 11th ‘00 592 95% 580 27th ICRC 2001

RUN 6 Dec 12th ‘00 Mar 24th ’03 821 98% 842 28th ICRC 2003

RUN 7 Mar 25th ’03 Feb 4th ‘05 666 >99% 881 29th ICRC 2005

RUN 8 Feb 5th ‘05 May 31st ‘07 846 >99% 936 30th ICRC 2007

LVD 4919 days rate of Galactic Gravitational Stellar Collapses

[D≤20kpc] < 0.18 event/year 90% c.l.

SUPER KAMIOKANDE rate of Galactic Gravitational Stellar Collapses

[D≤100kpc] < 0.32 event/year 90% c.l.

Galaxy survey

Piero Galeotti35

Vulcano 2008

The SNEWS The SNEWS NetworkNetwork

SuperNova Early Warning System

• Give prompt information to astronomical community.• Doing online coincidence, reduce to zero fake alarm.• Triangulation possible

LVDLVD SKSK

SNOSNO

BNLBNLserverserver

Every experiment looks for SN burst and send alarms at fixed rate (1/week); the network must be as much as possible fault tolerant.

Alarm to scientificcommunity

39Piero Galeotti Vulcano 2008