The document describes the Fluorescence detector Array of Single-pixel Telescopes (FAST) project. FAST aims to build an array of low-cost single-pixel fluorescence detectors spaced over large areas to study ultra-high energy cosmic rays (UHECR). Each FAST station would have 12 telescopes with 4 PMTs each, covering a 30°x360° field of view. An array of 500 stations over 150,000 km2 could achieve an exposure over 12 times that of the Pierre Auger Observatory. Simulations show FAST may achieve 10% energy resolution and 35 g/cm2 Xmax resolution for cosmic rays above 1019.5 eV. The full-scale FAST prototype has been constructed and work is ongoing to develop

1. Toshihiro Fujii, Max Malacari, Jose A. Bellido, Aygul Galimova, Pavel Horvath, Miroslav Hrabovsky,
Dusan Mandat, Ariel Matalon, John N. Matthews, Libor Nozka, Xiaochen Ni, Miroslav Palatka,
Miroslav Pech, Paolo Privitera, Petr Schovanek, Stan B. Thomas, Petr Travnicek
2016 2016 9 22
FAST 3

2. Fine pixelated camera
Low-cost and simplified/optimized FD
✦ Target : > 1019.5 eV, ultra-high energy cosmic rays (UHECR) and neutral particles
✦ Huge target volume ⇒ Fluorescence detector array
Too expensive to cover a huge area
2
Single or few pixels and smaller optics
Fluorescence detector Array of Single-pixel Telescopes
Segmented mirror telescope
Variable angles of elevation – steps.
15 deg 45 deg

3. 3
20 km UHECRs
16
56 EeV zenith 500
1
2
3
1
3 2
PhotonsatdiaphragmPhotonsatdiaphragm
Photonsatdiaphragm
Fluorescence detector Array of Single-pixel Telescopes
✦ Each telescope: 4 PMTs, 30°×30°
field of view (FoV).
✦ Reference design: 1 m2 aperture,
15°×15° FoV per PMT
✦ Each station: 12 telescopes, 48 PMTs,
30°×360° FoV.
✦ Deploy on a triangle grid with 20 km
spacing, like “Surface Detector
Array”.
✦ If 500 stations are installed, a ground
coverage is ~ 150,000 km2.
✦ Geometry: Radio, SD, coincidence of
three stations being investigated.

4. FAST Exposure
4
1.E+2
1.E+3
1.E+4
1.E+5
1.E+6
1.E+7
1.E+8
1990 2000 2010 2020 2030 2040
Exposures(L=km^2*sr*yr)
Year
Fly's Eye
AGASA
HiRes
Auger
JEM-EUSO
nadir
TAx4
JEM-EUSO
tilt
TA
✦ Conventional operation of FD under
15% duty cycle
✦ Target: >1019.5 eV
✦ Observation in moon night to achieve
25% duty cycle,
✦ Target: >1019.8 eV = Super GZK
events (Hotspot/Warmspot)
✦ Ground area of 150,000 km2 with 25%
duty cycle = 37,500 km2 (12×Auger,
cost ~50 MUSD)
✦ 1 TAx4
Auger 12
Preliminary
FAST

5. FAST
5
✦ EUSO-TA 1
✦
✦ 16
✦
✦ FAST
(Xmax)
EUSO-TA
telescope
+ FAST camera
Fig. 12. A 1018
eV shower simultaneously detected by the TA FD and the FAST prototy
superimposed (see Fig. 11). In (b), the corresponding FADC trace recorded by the FAST
Fig. 13. Correlation between the impact parameter and energy of the 16 cosmic ra
Fig. 6. FADC signal recorded for a YAP light pulse. It is used to monitor the relative gain
of the PMT.
Fig. 7. Variation of the YAP signal during a seven hour data taking run.
70 T. Fujii et al. / Astroparticle Physics 74 (2016) 64–72
Astroparticle Physics, 74 (2016) 64-72
Vertical Laser
~1019.3 eV
Cosmic Ray
~1018.0 eV

6. FAST - progress in design and construction
UV Plexiglass Segmented primary mirror8 inch PMT camera
(2 x 2)
1m2 aperture
FOV = 25°x 25°
variable
tilt
Joint Laboratory of Optics Olomouc – Malargue November 2015
Prototype - October 2015
15°
45°
6Joint Laboratory of Optics in Olomouc, Czech Republic
Full-scale FAST Prototype

7. 7
Full-scale FAST Prototype
Figure 5: The typical spectral reflectance of FAST mirror form
- 600 nm and spectral transmission of aperture filter. The red
represents the average reflectance and the blue dispersion of the
surements and the green curve represents the spectral transmissi
the FAST filter.
D. Mandat et al.
✦ 300 nm - 420 nm
✦
✦
Mirror
Filter
[nm]
/[%]

8. Ray-Trace Simulation
8420mm x 420 mm
Focal plane Bottom plane

9. Anode & dynode
Signal
DAQ System
TAFD external trigger, 3~5 Hz
Amplifiers
R979 CAEN
Signal×10
Camera of FAST, gain 5×104
High Voltage
power supply,
N1470 CAEN
Portable VME Electronics
- Struck FADC 50 MHz sampling,
SIS3350, 4 channels
- GPS board, HYTEC GPS2092
15 MHz
low pass filter
777,Phillips
scientific
Signal×50
×4

10. ch of the PMTs is prefixed
PMT number. We test the
by obtaining a single photo-
asurement. We place a single
output of the dual-channel
front of the PMT. The LED
00 kHz; typical LED ampli-
1.5 V and ⇡ 100 ns.
he PMT is connected to the
amplifier; the two resulting
to the FADC input and first
espectively. The PMT anode
FADC converts the signal to
of 0 to 4095 (12-bit range).
Time (2 ns)
800 1000 1200 1400
PMT ZS0018 PMT ZS0022
Integrated counts
0 2000 4000 6000 8000 10000 12000
20
Integrated counts
−200 −100 0 100 200
0
20
Integrated counts
−2000 0 2000 4000 6000 800010000120001400016000
0
50
−200 −100 0
0
10
PMT ZS0024 PMT ZS0025
Entries 23504
Mean 2111
RMS 2691
/ ndf2
175.6 / 85
Constant 2.3±184.8
Mean 30.6±4582
Sigma 21.9±1933
Integrated counts
0 5000 10000 15000 20000 25000
Entries
200
400
600
800
1000
1200
1400
Entries 23504
Mean 2111
RMS 2691
/ ndf2
175.6 / 85
Constant 2.3±184.8
Mean 30.6±4582
Sigma 21.9±1933
Entries 23504
Mean 0.857
RMS 55.09
/ ndf2
0 / −3
Constant 1.4±184.8
Mean 1.4±4582
Sigma 8350.8±1933
Integrated counts
−200 −150 −100 −50 0 50 100 150
Entries
0
20
40
60
80
100
120
140
160
Entries 23504
Mean 0.857
RMS 55.09
/ ndf2
0 / −3
Constant 1.4±184.8
Mean 1.4±4582
Sigma 8350.8±1933
Entries 43157
Mean 4210
RMS 6062
/ ndf2
263.4 / 104
Constant 2.1±161.5
Mean 34.5±9949
Sigma 42.9±2982
Integrated counts
0 5000 10000 15000 20000 25000
Entries
200
400
600
800
1000
1200
Entries 43157
Mean 4210
RMS 6062
/ ndf2
263.4 / 104
Constant 2.1±161.5
Mean 34.5±9949
Sigma 42.9±2982
Entries
Mean
RMS
/ ndf2
Constant
Mean
Sigma
−200 −100 0
Entries
0
50
100
150
200
250
300
Entries
Mean
RMS
/ ndf2
Constant
Mean
Sigma
FIG. 7. Integrated count distribution of SPE signals, includ-
ing pedestal (left peak) and SPE peak fitted to a Gaussian
for all PMTs.
After specifying the signal region for the averaged SPE
signal, we obtain a SPE integrated count distribution,
sometimes displayed as a charge distribution. Since some
events will have no photoelectrons (i.e. no charge), we
expect a peak centered around zero, called the pedestal.
PMT Calibration
10
(used in AirFly experiment)
Astroparticle Physics 42
(2013) 90–102
ysics, University of Chicago 8
Wavelength [nm]
600 700
avelength
UV Filter
out UV Filter
V, 75mV, x50 amp
ength
al
ground
al (with UV)
ground (with UV)
Bkgd
Entries 82
Mean 439.5
RMS 23.79
Counts
4
5
6
7
8
9
Bkgd
Entries 82
Mean 439.5
RMS 23.79
Background Rate (Without UV Filter)
Wavelength [nm]
200 300 400 500 600 700
Power[mW]
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
-9
10×
Power vs. Wavelength
With UV Filter
Without UV Filter
We report a final mean PMT detection e ciency of:
19.6% ± (0.1%)stat ± (2.0%)syst. This is in strong agree-
ment with the value provided by Hamamatsu (✏qe =
22%), assuming a standard collection e ciency for these
PMTs of approximately 90%.
PMT SPE P:V HV [V]* NL [%]** ✏390nm[%]
ZS0018 2.7 2585 -1.1 18.3
ZS0022 2.4 2252 -2.6 21.0
ZS0024 2.3 2266 -1.6 19.8
ZS0025 2.5 2369 -1.3 19.1
PMT Mean 2.5 ± 0.2 2368 ± 133 -1.7 ± .6 19.6 ± 2.0
Hamamatsu 2.5 2000 -2 19.8***
Tab. 3 Summary of characterization measurements
(*HV for G = 107
; **NL at IA ⇡ 60 mA; ***assuming
✏c ⇡ 90% for Hamamatsu)
Department of Physics, University of Chicago
FIG. 12. SPE peak height distribution used to set discrimi-
nator threshold value. The pedestal ends at around a height
of 350 ADC counts. Dividing this by the 4095 dynamic range
of the FADC gives a discriminator threshold of ⇡ 85 mV.
in wavelength. A NIST calibrated photodiode provides
Wavelength [nm]
0 100 200 300 400 500 600 700
Efficiency[%]
0
2
4
6
8
10
12
14
16
18
20
22
Detection Efficiency: FAST PMTs
Hamamatsu (Scaled)
PMT ZS0025
PMT ZS0024
PMT ZS0022
PMT ZS0018
18. HV = 2169V, Disc = 38mV, x20 Amp
22. HV = 2252V, Disc = 50mV, x20 Amp
24. HV = 2266V, Disc = 85mV, x20 Amp
25. HV = 2000V, Disc = 44mV, x20 Amp
FIG. 13. Detection e ciency results with Hamamatsu mea
surement for comparison.
the powermeter and monochromator initialized, any re
maining lights in the lab are switched o↵. The compute
in the lab is accessed remotely to begin data acquisi
tion. The DAQ program controls the monochromato
and powermeter. It obtains and averages 10,000 read
ings from the powermeter over 10 s for a given step; th
error, P , is calculated in quadrature from Poisson statis
tics on both powermeter readings, lamp signal and back
ground. The lamp background corresponds to when th
powermeter values are read out while the monochroma
tor shutter is kept closed; the lamp signal is obtained fo
an open shutter. The final power value used in calcu
lating detection e ciency is the di↵erence between thes
single-photo
electron
(SPE)
A. Matalon

11. 11
August 7th,
2016
September 14th,
2016

12. t 2253: log10(E(eV)): 18.57, Zen: 36.94◦
, Azi: 121.14◦
,
(-7.717, -8.908), S800: 12.29 VEM/m2
, Date: 20150511,
: 052034.035539
t 2254: log10(E(eV)): 18.53, Zen: 47.12◦
, Azi: 135.49◦
,
Event 2255: log10(E(eV)): 18.50, Zen: 33.03◦
, Azi: 136.36◦
,
Core(-4.088, 2.016), S800: 12.17 VEM/m2
, Date: 20150511,
Time: 070058.520151
Event 2256: log10(E(eV)): 19.76, Zen: 43.58◦
, Azi: 73.75◦
,
log(E(eV))
18 18.2 18.4 18.6 18.8 19 19.2 19.4 19.6
Efficiency
0
0.2
0.4
0.6
0.8
1 Proton
Iron
log(E(eV))
18 18.2 18.4 18.6 18.8 19 19.2 19.4 19.6
EnergyResolution[%]
0
5
10
15
20
25
Proton
Iron
log(E(eV))
18 18.2 18.4 18.6 18.8 19 19.2 19.4 19.6
]2
Resolution[g/cmmaxX
0
20
40
60
80
100
Proton
Iron
FAST Hybrid
✦ FAST
9/25
✦ FAST Hybrid
FAST → Energy: 10%, Xmax : 35 g/cm2 at 1019.5 eV
12
1.0 m × 1.0 m × 0.8 m
(350 kg)
(TASD)
(FAST)
simulation

13. 13
✦ Fluorescence detector Array of Single-pixel Telescopes (FAST)
✦
✦ 10
✦
✦ Full-scale FAST
✦
✦ 9/25
✦ FAST hybrid Energy Xmax
✦ Energy: 10%, Xmax: 35 g/cm2 at 1019.5 eV
http://www.fast-project.org
Comment from James W. Cronin (1931-2016)
I hope you can bring the single pixel fluorescence detector to
practical application. While most of my colleagues are pleased with
the results of Auger, I am disappointed we failed to find sources.
Instrumentation like yours may make that possible some day.