SYSTEMATICS
(preliminary
consideration)
V. Sinev
for Kurchatov Institute
Neutrino group
Common consideration
If the detectors, far and near, are absolutely
identical, the ratio of two measured
positron spectra Sfar and Snear is energy
independent:
SFar/SNear = 1 in no-oscillation case,
normalization: equal number of events
Detector differences can mimic or hide
oscillations
Following deviations from detectors identity
have been studied:
• Different energy resolutions Far, Near
• Different edge effects (positron annihilation
quanta escape) due to different detector
volumes VFar and VNear.
• Different light collection due to difference
in the light absorption lengths (440 nm)
Sfar/Snear for different energy
resolutions
Expected ratio for sin22q13=0.02,
Dm2 = 2.510-3 eV2
1.04
 far = 0.085 E
1.03
near = 0.075 E
1.02
1.01
1.00
0.99
0.98
0
1
2
3
4
5
6
Positron visible energy, MeV
Positron
visible energy, MeV
7
Sfar/Snear versus Detector volume
ratio Vfar/Vnear
Expected ratio for sin22q13=0.02,
Dm2 = 2.510-3 eV2
V1=1.2V2
1.02
1.01
1.00
0.99
0.98
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
1.03
V1=1.15V2
1.02
1.01
1.00
0.99
0.98
1.02
V1=1.1V2
1.01
1.00
0.99
0.98
0
1
2
3
4
5
6
7
Positron visible energy, MeV
Light collection vs source
position r and light attenuation
length  (440 nm)
Transparency
Transparency
Light
collection
the centre
Light
collection fromfrom
the centre:
5m
8m
9m
10 m
12 m
x=L(r)/L(0)
1.2
0.579
0.691
0.714
0.733
0.762
5m
8m
9m
10 m
1.1
12 m
1.0
0.0
0.5
1.0
1.5
Distance from the centre r, m
2.0
Light source position, m
2.5
Sfar/Snear for different
attenuation lengths far, near
Expected ratio for sin22q13=0.02,
Dm2 = 2.510-3 eV2
 near= 9.5 m
 far = 9 m
1.02
1.01
1.00
0.99
0.98
0
1
2
3
5
6
7
5
6
7
 near= 9 m
 far= 8 m
1.02
4
1.01
1.00
0.99
0.98
0
1
2
3
4
Positron visible energy, MeV
Positron visible energy, MeV
Neutron detection efficiency
vs neutron capture point
1.0
0.9
0.8
Efficiency
0.7
0.6
Neutron acceptance window is 1.7 - 2.8 MeV
0.5
0.4
0.3
0.2
0.0
0.5
1.0
1.5
2.0
distance from the centre, m
Distance
from the centre, m
2.5
Two gammas absorbed energy
versus the point of positron
annihilation
 E
Absorbed energy, MeV
1.2
1.0
0.8
0.6
0.4
0.2
0.0
0.0
0.5
1.0
1.5
Distance from the centre, m
2.0
Distance from the centre, m
2.5
OTHER OPTIONS
The Kr2Det scheme with two ~ 50
ton detectors at ~100 and 1000
meters uses available underground
rooms and does not require digging
new special caverns.
The oscillation signal could be
increased
(1) with the far detector at about
1500 m and (2) in a 3 detector
scheme: one near and two far
detectors at ~1400 and ~ 2700 m.
This increase will require larger
volume detectors, deeper detector
positions and digging new underground halls.
Sfar/Snear at different detector positions
Dm2 = 2.510-3 eV2
2
1.72
1.6
1.2
posi
0.8
0.4
fari  3
2.83310
rat i 
neari
0
0
1
2
3
0
4
5
6
7
8
ei
8
1.01
1.01
1.009
1.01
neari
fari
1
rat i
rat i 
1.008
1.007
1.006
1.005
1.004
1.003
1.002
1.001
1
0.999
0.998
0.997
0.996
0.995
0.994
0.993
0.992
0.991
0.99
i  0  70
1000/100
0.99
0.99
far
i
neari
0
1
2
3
0
4
5
6
7
xi
8
8
1.01
1.01
neari
fari
1
rat i
1.01
1.009
1.008
1.007
1.006
1.005
1.004
1.003
1.002
1.001
1
0.999
0.998
0.997
0.996
0.995
0.994
0.993
0.992
0.991
0.99
0.99
0.99
i  0  70
ei  1.0  0.1  i
1900/100
0
1
2
3
0
1
2
3
0
sig i 
 ei
  
 

 ( 1.71465  8.874  0.6931472)

 
( 2.628)
4
5
4
5
xi
6
 0.8  1.293



2
6

 ei


Visible energy, MeV
0.511
7
8
7
8
8
 0.8  1.293

0.511
2
 1

fari
rat i 
neari
1.01
1.01
1.01
1.009
1.008
1.007
1.006
1.005
1.004
1600/900
1.003
1.002
neari
1.001
1
fari
1
rat i
0.999
900/100
0.998
0.997
0.996
0.995
0.994
0.993
1600/100
0.992
0.991
0.99
0.99
0.99
rat i 
0
1
2
3
0
fari
4
5
6
7
8
xi
8
neari
1.01
1.01
1.01
1.009
1.008
1.007
1.006
2600/1300
1.005
1.004
1.003
1.002
neari
1.001
fari
1
rat i
0.999
1
1300/100
0.998
0.997
0.996
0.995
2600/100
0.994
0.993
0.992
0.991
0.99
fari
0.99
rat i 
0.99
0
1
2
3
0
4
5
6
7
xi
8
8
neari
1.01
1.01
1.009
1.01
neari
fari
1
rat i
1.008
1.007
1.006
1.005
1.004
1.003
1.002
1.001
1
0.999
0.998
0.997
0.996
0.995
0.994
0.993
0.992
0.991
0.99
0.99
0.99
3600/1800
3600/100
1800/100
0
0
0
1
1
2
2
3
3
4
5
4x
5
i
6
7
8
6
7
88
Visible energy, MeV
Possible experimental result for
ratio at Krasnoyarsk
40 thousand events at far detector
1.04
1.02
1.00
0.98
0.96
0
1
2
3
4
5
6
7
Visible positron energy, MeV
1.04
80 thousand events at far detector
1.02
1.00
0.98
0.96
0
1
2
3
4
5
6
Visible positron energy, MeV
7
Conclusion
We estimated some effects which can
influence the ratio to mimic effect of
oscillation
Kr2Det uses available underground
halls for far (1000m) and near (115m)
50-ton detectors
The oscillation signal could be
somewhat increased with the Far
detector at ~ 1400-1900 m or with two
far detectors at ~ 1300 and 2600 m…
This however would require digging
new caverns and using detectors of
larger target masses…
Letter of Intention
I.R.Barabanov, L.B.Bezrukov,
V.I.Gurentsov,V.N.Kornoukhov,
E.A.Yanovich
Institute for Nuclear Research of RAS
(Moscow, Russia)
N.A.Danilov, G.V.Korpusov, Yu.S.Krylov
Institute of Physical Chemistry of RAS
(Moscow, Russia)
Development of a recipe and
production of components for a
liquid scintillator doped with Gd
for K2Det or Kashiwazaki
experiment.
1. Development of test batches of Gdcompound for a liquid scintillator.
Based on experience in the framework of
LENS Collaboration on the development of
Yb-loaded scintillator with characteristics:
LY = 60% of BC 505; (8% of Yb),
L1/2 (430 nm) ~ 2.5 m (8% of Yb), ^ when c dec.
we propose to develop and synthesized
Gd-loaded LS replacing in our Yb-Carboxylate
compound Yb by Gd because of their
common chemical properties (even more
difficult for Yb).
M ~ 2 x 150 kg
(0,3% of Gd)
The procedure is just simple blending
“Gd-compound + solvent”.
2. Production, purification and certification of an effective primary
fluorescent additive (fluor)
BPO, 2[4-biphenyl]5-phenyl oxazole.
Light Yield of BPO is ~ 50% more than
LY of PPO.
M = ~ 2 x 100 kg
Development of new fluor with maximum
emission in 430-440 nm
3. Delivery of organic base (a
solvent) for LS with a high flash
point (~ 80oC).
M ~ 100 t
•Light output 80% of Whitespirit
•Composition H/C ~1.8
•Transparency >10 m
•Radio purity is low but should be
investigated
•Chemical activity - weak
If LS has H:C ~ 2 (for example, Palo
Verde and CHOOZ experiment):
Then for Gd = 0% (100% captured
probabilities with E = 2.2 MeV):
 = 180 sec
for Gd = 0.1%
(86% captured
probabilities with E ~ 8 MeV, well above
the natural radioactivity):
 = 32  2% sec