Transcript Slides - indico in2p3

Calculation of detector
characteristics for KM3NeT
-storey properties
-fluxes and rates
-sources
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Christopher Lindsay Naumann - Geometry studies for KM3NeT
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Mean photocathode surface (revision)
can calculate “mean photocathode surface” for
a single storey from
φ
•properties of PMTs (size, angular acceptance)
θphot
•positioning and number of OMs
α
βtilt
dpmt
z
“ANT”
“MULTI”
θμ
-mean surface for light: response to plane wave
“NEMO4”
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-mean surfaces for muons:
integration over all light emission directions
Christopher Lindsay Naumann - Geometry studies for KM3NeT
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Mean surfaces for all storey types (without QE)
2
Pphotocathode
K surface, cm
surface [cm2]
mean photocathode surface
as function of light direction
(plane wave)
1400
ANT
MULTI
NEMO-4
NEMO-6
1200
1000
800
600
400
200
…and as function of
muon direction (theta)
light
deg
45
90
135
180
2
P K surface, cm
photocathode
surface [cm2]
1200
gives a measure for the
acceptance for up- and
downgoing muon events.
have to scale with quantum
+ collection efficiency
ANT
MULTI
NEMO-4
NEMO-6
1000
800
600
400
200
muon
deg
45
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135
180
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Effective detection range
Photocathode surface also defines range in which a muon can be
detected (absorption, dilution)
-> “effective detection range” Rdet(Eμ,θμ) for a muon of energy Eμ, dir. θμ
Pdet>50%
-> defines an active “pixel size”
around each storey at a certain p.e.
threshold (e.g. 2 p.e. for “L1”)
Rdet
Pdet<50%
 simple toy Monte-Carlo study:
-generate “tracks” (straight lines)
-count number of Rdet spheres hit
-apply “trigger” criterion (e.g. 5L1)
300
2 p.e.
2perange
range m [m]
200
150
100
70
50
ex.: ANT
storey
30
20
15
10
1
0
1
2
E
3
4
--> “trigger efficiency”
--> effective areas (μ and )
TeV
log10Eμ [TeV]
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2 p.e. response of the detector to a 10 TeV track
“muon” track
Geometry only ! No timing info !
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Christopher Lindsay Naumann - Geometry studies for KM3NeT
“touched” (triggered) storeys
(at least 2 p.e. with P>50%)
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Comparison with existing results
Comparison with results from
existing Monte-Carlo:
100
10
1
Tower Design
4-OM
points: existing MC
curves: this work
0.1
0.01
0.001
0
1
A [m2]
A [m2]
very good agreement with
detailed Monte-Carlo
(NEMO group + S. Kuch)
100
10
100
10
Tower Design
6-OM
2
3
1
0.1
1
CUBOID
geometry,
thesis S. Kuch
0.1
0.01
0
1
2
data: Coniglione
et al, Paris 10/08
0.01
0
1
2
3
log10E [TeV]
3
also: qualitative results (influence of string or storey distance, etc)
reproduced.
Simple tool but works well (at least for guidance / qualitative results)
and much faster than full physics Monte-Carlo !
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Comparison of KM3NeT architectures
string and tower architectures, normalised to 1km3 inst. volume
String Design (“SD”)
Tower Design (“TD”)
Δ lines = 95m
Δ towers = 140m
Δ storeys = 25m
Δ storeys = 40m
20 storeys per string
18 storeys per tower
256 strings (1km3)
100 towers (1km3)
ANT-type storeys:
15360 OMs
4-OM bars (TD-4):
7200 OMs
MULTI-PMT storeys:
5120 OMs ×31 PMTs
6-OM bars (TD-6):
10800 OMs
?
?
KM3NeT
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2
1
0
1
2
3
normalised to same volume:
•here SD more sensitive
(higher OM density)
SD-ant
SD-multi
TD-4
TD-6
1
0
1
2
log10 E TeV
effective area per
photocathode area:
at high energies, TD-4 best
(fewest OMs), worst at low
energies
•TD-6 better than TD-4 at low E
3
log10 Aeff Spk
log10 Aeff m2
Comparison: neutrino effective areas (2π up-going)
0
1
2
3
4
5
6
SD-ant
SD-multi
TD-4
TD-6
1
0
1
2
log10E TeV
3
no reconstruction-> “single-tower” advantage of the TD not included !
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Expected source rates - examples
use the 1km3 designs with expected fluxes for HESS sources (see talk
later…)
angular resolution 0.1°, energy res. ΔlogE=0.5, 5 years
DET
S(B)>5TeV
nσ
P(3 σ)
Ecut
SD-ant
3.1 (8.2)
1.1
12%
160TeV
TD-4
1.9 (4.1)
0.9
13%
126TeV
TD-6
2.4 (6.1)
1.0
10%
160TeV
probability for 3
sigma in 5 years
Vela-X
(PWN)
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RXJ1713
(SNR)
optimum energy cut
DET
S(B)>5TeV
nσ
P(3 σ) Ecut
SD-ant
5.1 (3.3)
2.8
47%
10 TeV
TD-4
3.4 (1.7)
2.6
48%
5 TeV
TD-6
4.2 (2.5)
2.7
45%
8 TeV
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Conclusions and Outlook
Mean storey surface gives relative sensitivity to up- and
downgoing tracks
Detection range calculation allows fast estimate of
detector properties -> toy model Monte-Carlo
Effective areas and systematic effects in good
agreement with existing work
-> extrapolate to different total volume / PK surface,
quantum efficiency, absorption length, PMT size…
-> can generate approximate effective areas for event
rate calculations
Thank you !
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Backup slides
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Storey types studied
ANTARES-type storey:
optical modules with ANTARES-type 10”
PMT (curved photocathode)
3 optical modules per storey, tilted
downward by 45° (or variable)
Multi-PMT storey:
31 x 3” PMT distributed in sphere
flat angular response
single, downward looking OM per storey
NEMO-type storey:
10” PMT (as for ANTARES)
4 optical modules per storey:
2 x horizontal, 2 x vertical down
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Average photocathode area for neutrinos and muons
weighted by expected
quantum efficiencies:
mean photocathode area per
storey integrated over all muon
directions (isotropic flux)
ANT/NEMO: 32%
MULTI-PMT: 42%
350
1200
1000
Downgoing
Upgoing
300
Downgoing
Upgoing
250
800
200
600
up to now, have ignored
quantum efficiency !
150
400
100
200
50
0
0
ANT
down
up
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38%
MULTI
75%
NEMO
51%
Christopher Lindsay Naumann - Geometry studies for KM3NeT
ANT
MULTI
NEMO
=> NEMO surfaces per storey
largest… but uses 4 OMs !
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Qualitative results, example: line distance in string architecture
string architecture (100 string grid, 25m
storey distances) with ANT storeys
detection
probability
Pdet
1
1.0
50m
0.8
.8
String distances:
0.6
.6
0.4
.4
85m, 100m, 150m, 200m, (50m)
200m
.2
0.2
0-11
0.0
0
0
1
1
log10Eμ [TeV]
Aeff [km2]
Aeff km 2 μ
2
2
33
log 10 E
200m
5.00
5
TeV
As expected, improvement for larger
dS at higher energies; break point
slightly below 10 TeV
In good agreement with results from
NESSY and Sebastian Kuch
85m
1.00
1
0.50
0.5
0.10
0.1
0.05
0.05
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1
1
2
2
3
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log10TeV
Eμ [TeV]
log 10 E
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