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

LVD

Presenters: AGAFONOVA NATALIA

BOYARKIN VADIM


Corno Grande


LVD

H=3650 m.w.e.


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


1m

1,5m

1m

L-shape

tracking

system

Module – portatank,

8 sc


The Tower


  • 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


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


А

t

T

How can the neutrino burst be identified ?

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


Reactions for scintillation and Cherenkov counters

MeV

cm2

MeV

cm2

cm2

cm2


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


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


Tower Quarters

4Q


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


neutrons

nFe-capture

nth

p

 (~7MeV)

nth

n

 (2.2 MeV)

np-capture

p

,

,


single muon

72294

Neutrons=

5133.7

843.4

0-4 MeV

4-12 MeV


muon bundles

23502

N=72294

Neutrons=

5949.6

908.2


0

-

+

n

e+e-

hadronic and

electromagnetic

cascades

19603

Neutrons=

18537

2684


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


δ=0.07

4.3810-4

Per 1  (all processes)

7


LVD

En>0MeV

8


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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