Supernovae Explosion Detection
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Supernovae Explosion Detection vs Neutron Background on Example of Underground Detector. LVD. Presenters: AGAFONOVA NATALIA BOYARKIN VADIM. Corno Grande. LVD H=3650 m.w.e. H min =3650 m.w.e. <E  >=280 GeV E  th = 2.2TeV at sea level.

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Supernovae Explosion Detection vs Neutron Background on Example of Underground Detector

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Supernovae explosion detection vs neutron background on example of underground detector

Supernovae Explosion Detection

vs Neutron Background

on Example of

Underground Detector

LVD

Presenters: AGAFONOVA NATALIA

BOYARKIN VADIM


Supernovae explosion detection vs neutron background on example of underground detector

Corno Grande


Supernovae explosion detection vs neutron background on example of underground detector

LVD

H=3650 m.w.e.


Supernovae explosion detection vs neutron background on example of underground detector

Hmin=3650 m.w.e. <E>=280 GeV Eth = 2.2TeV at sea level

-rate (1 tower)~ 120 h-1

Stopping muon rate

(1 counter) 0.7510-3

  • - trigger: ε 40 MeV, 2 sc

Data taking trigger:

th=4MeV

(inner counters)

th=7MeV

(external counters)

Event duration – 1 ms,

th=0.6MeV (inner counter)

E–resolution: ~30% =1-5MeV

~20%  5 MeV

t–resolution: ~70 ns


Supernovae explosion detection vs neutron background on example of underground detector

1m

1,5m

1m

L-shape

tracking

system

Module – portatank,

8 sc


Supernovae explosion detection vs neutron background on example of underground detector

The Tower


Supernovae explosion detection vs neutron background on example of underground detector

  • The large volume detectors are the underground observatories for:

  • Neutrino astrophysics

  • Cosmic Rays physics

  • Search for point sources of cosmic rays

  • Study of neutrino oscillations

  • Search for rare events predicted by the theory (proton decay, monopoles, dark matter...)

  • - Geophysical phenomena


Supernovae explosion detection vs neutron background on example of underground detector

General idea

How can one detect the neutrino flux from collapsing stars?

Until now, Cherenkov (H2O)andscintillation (СnH2n) detectors which are capable of detecting mainly , have been used in searching for neutrino radiation, This choice is natural and connected with large -p cross-section

As was shown at the first time by G.T.Zatsepin, O.G.Ryazhskaya, A.E.Chudakov (1973), the proton can be used for a neutron capture with the following production of deuterium (d) with  - quantum emission with 180 – 200 µs.

The specific signature of event


Supernovae explosion detection vs neutron background on example of underground detector

А

t

T

How can the neutrino burst be identified ?

The detection of the burst of N impulses in short time interval T


Supernovae explosion detection vs neutron background on example of underground detector

Reactions for scintillation and Cherenkov counters

MeV

cm2

MeV

cm2

cm2

cm2


Supernovae explosion detection vs neutron background on example of underground detector

Yu.V. Gaponov, S.V. Semenov

e

СnH2n

1+ GT __________10,589

1+ GT __________ 7,589

1+ GT __________ 4,589

0+ IAS __________ 3,589

1+ __________ 1,72

4+ __________

0+

So one can expect 550 events from

and more than 700 events from &

in LVD


Supernovae explosion detection vs neutron background on example of underground detector

The possibility to observe the neutrino burst depends on background conditions

The source of background:

  • Cosmic rays 0<E<

  • а) muons

  • b) secondary particles generated by muons(e,,nand long-living isotopes)

  • с) the products of reactions of nuclear and electromagnetic interactions

  • 2. Natural radioactivity Е<30 MeV, mainly Е<2.65 MeV

  • а) ,

  • b) n,(n ), U238, Th232

  • c) , (n) d) Rn222

Background reduction:

1. Deep underground location

2. Using the low radioactivity materials

3. Anti-coincidence system

4. Using the reactions with good signature

5. The coincidence of signals in several detectors


Supernovae explosion detection vs neutron background on example of underground detector

Tower Quarters

4Q


Supernovae explosion detection vs neutron background on example of underground detector

C=

5 4 3 2 1

7

6

5

4

3

2

1

L

10.2 m

6.3 m

13.4 m

1 TOWER

280 scintillation counter

(1.2 t/counter)

120 inner counters

3 TOWERS total

840 sc

1kt – scintillator

1kt – Fe


Supernovae explosion detection vs neutron background on example of underground detector

neutrons

nFe-capture

nth

p

 (~7MeV)

nth

n

 (2.2 MeV)

np-capture

p

,

,


Supernovae explosion detection vs neutron background on example of underground detector

single muon

72294

Neutrons=

5133.7

843.4

0-4 MeV

4-12 MeV


Supernovae explosion detection vs neutron background on example of underground detector

muon bundles

23502

N=72294

Neutrons=

5949.6

908.2


Supernovae explosion detection vs neutron background on example of underground detector

0

-

+

n

e+e-

hadronic and

electromagnetic

cascades

19603

Neutrons=

18537

2684


Supernovae explosion detection vs neutron background on example of underground detector

For determining the specific neutron yield

number we used the formula:

the number of searched events

the average muon path length

total number of muon events both

single muons and groups, and

electromagnetic and hadronic cascades

6


Supernovae explosion detection vs neutron background on example of underground detector

δ=0.07

4.3810-4

Per 1  (all processes)

7


Supernovae explosion detection vs neutron background on example of underground detector

LVD

En>0MeV

8


Supernovae explosion detection vs neutron background on example of underground detector

q=(VFe+VPVC)/(VFe+VPVC+Vsc)

q=0.160

V(M pvc=380kg) =0.86 m3

MFe =9.46t

=7.8 g/cm3

Msc=9.2 t

=0.78 g/cm3

K=240/146=1.644

sc = 0.9

Fe,Cl = 0.75


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