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Search for neutrinos from collapsing stars in Italy (a 30 years report) C. Castagnoli, K. Lande, O. G. Ryazhskaya, O. Saavedra G. T. Zatsepin …..and many others. CNB. Supernova. Solar. Atmospheric. Sources. - PowerPoint PPT Presentation
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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
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3Piero Galeotti Vulcano 2008
Sun
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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.
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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
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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
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+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.
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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
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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).
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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%.
-
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LVD 10 LVD 10 yearsyears
High duty cycle (>99.5% since 2002)
Fiducial Active Mass (M~ 900 tons since Jun/2001) 32
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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
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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