future application of sipms for the fluorescence detection of … · 2019. 1. 16. · luís mendes,...
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OBSERVATORY
Future application of SiPMs for the fluorescence detectionof extensive air showers
Lukas Middendorf
Physics Institute IIIA
Digital Counting Photosensors for Extreme Low Light LevelsLisbon, 20.4.2012
Lukas Middendorf SiPMs for fluorescence detection of EAS 1
Outline
1 Extensive Air Showers
2 The Pierre Auger Observatory
3 FAMOUS – SiPM based fluorescence telescopeDesignExpected Performance
4 Summary & Outlook
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Lukas Middendorf SiPMs for fluorescence detection of EAS 2
Cosmic ray induced extensive air showers (EAS)
Earth atmosphere is constantly hit by cosmic ray particles with energiesup to several 1020 eVvery low flux⇒ no direct detection possible⇒ use earth atmosphere as calorimeter with large ground based detectorinteraction of particles with air produces multiple secondary particles⇒ extensive air showers down to the ground level
Lukas Middendorf SiPMs for fluorescence detection of EAS 3
Fluorescence detection of extensive air showers
edge of atmosphere
ground
X1
number of p
articles,
N
Xm
axslant
depth
θ
path of shower
fluorescence light
Xtelescope
FOVfluorescence lig
ht
air emits fluorescence light isotropicallywhen excited by shower particles (UV)light ∝ number of particles ∝ energymeasure longitudinal air showerdevelopmentdetermine energy and Xmax
[nm]λfluorescence photon wavelength250 300 350 400
Inte
nsity
Lukas Middendorf SiPMs for fluorescence detection of EAS 4
The Pierre Auger Observatory
hybrid cosmic ray detector for energies above 1018 eVin Argentine Pampameasures properties of extensive air showers
Surface Detector1600 water-Cherenkovdetector stations1.5 km tank spacingmeasures lateral distribution
Fluorescence Detector4 fluorescence telescope sites24 telescopesat array bordersfield of view (FOV) per site:6 · 30 × 30
Lukas Middendorf SiPMs for fluorescence detection of EAS 5
A Fluorescence Telescope
Schmidt cameraaperture diameter 2.2 m3.8× 3.8m2 mirror30 × 30 field of view (FOV)UV-pass filter
440 hexagonally arranged PMTs1.5 FOV per pixelPMT quantum efficiency ≈ 30%
Lukas Middendorf SiPMs for fluorescence detection of EAS 6
A Fluorescence Telescope
Schmidt cameraaperture diameter 2.2 m3.8× 3.8m2 mirror30 × 30 field of view (FOV)UV-pass filter
440 hexagonally arranged PMTs1.5 FOV per pixelPMT quantum efficiency ≈ 30%
Lukas Middendorf SiPMs for fluorescence detection of EAS 6
FAMOUS
First Auger Multi-pixel-photon-counter camera for the Observation ofUltra-high-energy air Showers
Small prototypefluorescence telescope for the measurement of extensive air showers
with silicon photomultipliers
Developed in Aachen, Granada and LisbonPedro Assis, Pedro Brogueira, Antonio Bueno, Miguel Ferreira, Josef Grooten, Thomas Hebbeker, Markus Lauscher,
Luís Mendes, Lukas Middendorf, Sergio Navas, Tim Niggemann, Barthel Philipps, Mário Pimenta, Angel Ruiz,Maurice Stephan, Franz-Peter Zantis
Lukas Middendorf SiPMs for fluorescence detection of EAS 7
SiPMs for
much higher possible photon detection efficiency (∼ 70%) compared tocurrently used PMTs (∼ 30%)demonstrated in prototypes (not currently available for purchase)better angular resolution possible
Build now to learn by manufacturing and demonstrate feasibility
Use Hamamatsu S10985-100C 2× 2 array with 100µm pitch (6× 6mm2
total size), ≈ 30% PDE in UV range
3.0 3.0
ch1 ch4
ch2 ch3
0.4
3.0
3.0
9.0±0.15
8.2 ± 0.15
Lukas Middendorf SiPMs for fluorescence detection of EAS 8
Basic telescope design
Fresnel lens Tube Camera pixels
510 m
m
107 m
m
OA
Focal plane
510 mm
simple refractive design
Lukas Middendorf SiPMs for fluorescence detection of EAS 9
1.5 field of view per pixel
Fresnel lens
remove thick “dead material” of lens⇒ concentric annular sections (“grooves”)approximate curved surface with linearslopeskeeps refraction power of original lens
reduced weightreduced absorptioncheap
compromise in image quality(bigger spot size)
small f /D possible⇒ much light per solid angle⇒ big field of view
Cut thick parts
groove
groove depth
Lukas Middendorf SiPMs for fluorescence detection of EAS 10
Fresnel lens
D = 510mmf = 510mmUV-transparentplastic (PMMA)
Lukas Middendorf SiPMs for fluorescence detection of EAS 11
Point spread function
Distribution of photons in focal plane
x / mm
6 4 2 0 2 4 6
y /
mm
6
4
2
0
2
4
6
rela
tiv
e i
nte
ns
ity
0
5
10
15
20
25
310×
= 1.6 mm90
R
° = 0 in
θ
Optical System
Object Plane Focal Plane
LightLightSpotSpot
90% of light included inred circle R90: 1.6mm≈ 100% included in pixel(green)
simulation with Geant4
point size sufficient for 1.5 field of view per pixel
Lukas Middendorf SiPMs for fluorescence detection of EAS 12
Focal planemodular designhexagonal arrangement of pixelsone pixel: Winston cone (light concentrator) and 6× 6mm2 SiPM arrayUG-11 UV-pass filter64 pixels plannedmanufacturing test with 7 pixels
SiPMs
Light
Lukas Middendorf SiPMs for fluorescence detection of EAS 13
Winston cones
light concentrator
x [mm]-8 -6 -4 -2 0 2 4 6 8
z[m
m]
0
5
10
15
20 optical axis1r
2rcone
maxθ
light up to θmax is collected
tilted paraboloid surfacelight concentrated by factor 5maximum transmitted incidentangle θmax = arcsin(r2/r1) = 26.6
high exit angles up to 90
Lukas Middendorf SiPMs for fluorescence detection of EAS 14
Emergent angle of light from Winston cone
/ degout
θemergent angle 0 10 20 30 40 50 60 70 80 90
fracti
on
en
trie
s / t
ota
l co
un
t
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0.22 ° = 0 in
θincident angle
° = 26 in
θincident angle
= 6.7 mm1r
= 3.0 mm2r
Lukas Middendorf SiPMs for fluorescence detection of EAS 15
Angle dependence of PDE
measured in AachenUse LED to illuminateSiPMnormalize signal to 0
correct for projection ofactive area
measurements can bedescribed by Fresnel equation(transmission and reflectionon surface of SiPM)
90% relative PDE up to incident angles of 60
Lukas Middendorf SiPMs for fluorescence detection of EAS 16
Readout electronics
based on MAROC3 chip64 channels (threshold)8 analogue sums (of 8channels)internal ADCs
individual control of bias voltagefor each pixelFPGA handles all digital functionsincluding trigger
design and production:Lisbon
SiPM signals
trigger &digitalization
digitalizedsignals
first prototype currently in productionLukas Middendorf SiPMs for fluorescence detection of EAS 17
Simulation of
Conex ShowerSimulation
Conex ShowerSimulation
EminEmax
ϕ ,θ
particle
interaction model
Auger OfflineSoftware
Auger OfflineSoftware Geant4Geant4
Fluorescence LightSimulation
Root Export
Modules
Atmosphere
Photon Propagation
telescope geometrynight-sky measurementsSiPM characterization
ComponentsComponents
Winston ConesWinston Cones
Fresnel LensFresnel Lens
SiPMsSiPMs
shower profile photons
shower distance
Lukas Middendorf SiPMs for fluorescence detection of EAS 18
event display
simulated vertical 1018.25 eV proton shower in 2 km distance
Lukas Middendorf SiPMs for fluorescence detection of EAS 19
Simulation of SiPM voltage traces
t / ns
18000 20000 22000 24000 26000 28000 30000
V /
mV
6000
5000
4000
3000
2000
1000
0
nightsky brightness
air shower
Aachen
baseline
phenomenological simulation of SiPM in progressLukas Middendorf SiPMs for fluorescence detection of EAS 20
1018 eV proton shower2 km shower distance
simulation
Expected performance
Expected event rates of air showers in Aachen for different energies E andshower distances Rp
(E/eV)10
log14 15 16 17 18 19
/ k
mp
R
2
4
6
8
10
12 1even
ts d
ay
710
610
510
410
310
210
110
11Integral = 16 events day
S/N > 3
= 12 degfov
α
= 3.14 sr0Ω
= 10 %∈duty cycle Noise in Aachendominated by skybackground (90%):≈ 10 photonsper 33 ns - time binper pixel
Multiple events per night possible, even in AachenLukas Middendorf SiPMs for fluorescence detection of EAS 21
au Integral = 16 events per dayaaa
Summary & Outlook
Summaryextensive SiPM characterization studies doneoptical design for the new SiPM prototype fluorescence telescope
chosenDAQ and trigger electronics currently under developmentmechanical production partly donesimulations of make great progress
Outlookfinalize and build electronicsbuildfirst light this year
Lukas Middendorf SiPMs for fluorescence detection of EAS 22
Backup
Backup
Lukas Middendorf SiPMs for fluorescence detection of EAS 23
Absorption of Fresnel lens
[nm]λwavelength
200 300 400 500 600 700 800 900 1000
tra
ns
mis
sio
n T
[%
]
0
20
40
60
80
100
fluorescence light
Transmission of PMMA 8N (Reflexite, October 2004, d=3mm thickness)
]1
[m
mα
ab
so
rpti
on
co
eff
icie
nt
0
0.1
0.2
0.3
0.4
0.5
0.6
dln T = α
Transmission is > 90% for λ > 350 nm
Lukas Middendorf SiPMs for fluorescence detection of EAS 24
SiPM characterization studies in Aachen
temperature dependent breakdown-Voltagephoton detection efficiency
wavelength dependentovervoltage dependentangle dependent
crosstalk probabilityafterpulse probabilitytemperature dependent thermal noise rate
Lukas Middendorf SiPMs for fluorescence detection of EAS 25