Toshihiro Fujii, Max Malacari, Jose A. Bellido, Bruce Dawson, Pavel Horvath, Miroslav Hrabovsky, Jiaqi Jiang, Dusan Mandat, Ariel Matalon, John N. Matthews, Pavel Motloch, Libor Nozka, Palatka, Miroslav Pech,

Paolo Privitera, Petr Schovanek, Stan B. Thomas, Petr Travnicek2016/Feb/29, UHEAP 2016 workshop

Next-Generation Observatory: Fluorescence detector Array of Single-pixel Telescopes (FAST)

arXiv: 1504.00692

Physics Goal and Future ProspectsOrigin and Nature of Ultra-high Energy Cosmic Rays and

Particle Interactions at the Highest Energies

Exposure and Full Sky CoverageTA4 + AugerJEM-EUSO : pioneer detection from space and sizable increase of exposure

Detector R&DRadio, SiPM, Low-cost Detectors

Precision Measurements AugerPrime Low energy enhancement(Auger infill+HEAT+AMIGA,TALE+TA-muon+NICHE)

5 - 10 years

Next Generation ObservatoriesIn space (100exposure): EUSO-NextGround (10exposure with high quality events): Giant Ground Array, FAST

10 - 20 years

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

3

Single or few pixels and smaller optics

Fluorescence detector Array of Single-pixel Telescopes

Segmented mirror telescope Variable angles of elevation steps.

construction is still in development

15 deg 45 deg

Joint Laboratory of Optics Olomouc March 2014 7

4

20 km UHECRs

16

56 EeV zenith 500

1

2

3

1

3 2

Pho

tons

at d

iaph

ragm

P

hoto

ns a

t dia

phra

gm

Pho

tons

at d

iaph

ragm

Fluorescence detector Array of Single-pixel Telescopes Each telescope: 4 PMTs, 3030

field of view (FoV).

Reference design: 1 m2 aperture, 1515 FoV per PMT

Each station: 12 telescopes, 48 PMTs, 30360 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.

FAST Exposure

5

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

Expo

sure

s (L

=km

^2*s

r*yr

)

Year

Fly's Eye

AGASA

HiRes

Auger

JEM-EUSO nadir

TAx4

JEM-EUSO tilt

TA

Conventional operation of FD under 10~15% duty cycle

Target: >1019.5 eV

Observation in moon night to achieve 25% duty cycle,

Target: >1019.8 eV = Super GZK events (Hotspot/Warmspot)

Test operation by Auger FD (Radomir Smida).

Ground area of 150,000 km2 with 25% duty cycle = 37,500 km2 (12Auger, cost ~50 MUSD)

Preliminary

FAST

Window of Opportunity at EUSO-TA

6

EUSO prototype

Telescope Array site Black Rock Mesa station

Temporally use the EUSO-TA optics at the TA site.

Two Fresnel lenses (+ 1 UV acrylic plate in front for protection)

1 m2 aperture, 1414 FoV FAST reference design.

Install FAST camera and DAQ system at EUSO-TA telescope.

Milestones: Stable observation under large night sky backgrounds, UHECR detection with external trigger from TAFD.

EUSO-TA telescope FAST camera

8 inch PMT (R5912-03, Hamamtsu)

PMT base (E7694-01, Hamamatsu)

Ultra-violet band pass filter (MUG6, Schott)

7

Start observation

1 2 3

4 5 6

7 8 9

Laser Signal to Check Performance

8Time (100 ns)

0 100 200 300 400 500 600 700 800

/ (1

00 n

s)p.

e.N

0

50

100

150

200

250

300

350Data

Simulation

FAST FOV

Hit clouds

Directional sensitivity by RayTrace of

EUSO-TA telescope

Efficiency

TAFD

FAST

Np.

e. /(

100

ns)

Vertical Ultra-Violet laser at 6 km from FAST ~1019.2 eV

Expected signal TAFD/FAST: (7 m2 aperture 0.7 shadow 0.9 mirror) / (1 m2 aperture 0.43 optics efficiency) ~10

TAFD Peak signal : ~3000 p.e. / 100 ns

FAST Peak signal : ~300 p.e. / 100 ns. All shots are detected significantly.

Agreement of signal shape with simulation.

UHECR Signal Search

FAST FoV

Data set: April and June 2014 observation, 19 days, 83 hours.

Stable observation.

We searched for UHECR signal in coincidence between FAST and TAFD.

1. Search for TAFD signal crossing the field of view (FoV) with FAST.

2. Search for a significant signal (>5) with FAST waveform at the same trigger.

16 candidates found.

Low energy showers as expected.

log(E/eV)=18.0

Np.

e. /

(100

ns)

9

TAFD

FAST

Time (100 ns)0 100 200 300 400 500 600 700 800

/ (1

00 n

s)p.

e.N

-20

0

20

40

60

80

(E (eV))10

log17 17.5 18 18.5 19 19.5 20

Impa

ct p

aram

eter

[km

]

1

10

210Preliminary

Detect

able

Figure 14: Distribution of the impact parameter as a function of the primary energy recon-

structed by TA for shower candidates detected by the FAST prototype. The line indicates

the maximum detectable distance by the FAST prototype (not fitted).

20

Distance vs Energy (from TAFD) for Candidates

10

FAST FoV

Almost! log(E/eV)=19.1

log(E/eV)=18.0

Results on the First Field Observation Data set: April and June 2014 observation, 19 days, 83 hours

Very stable observation under large night sky backgrounds

Laser detection to confirm a performance of the prototype

UHECR search : 16 candidates coincidence with TA-FD

Very successful example among Telescope Array, JEM-EUSO, Pierre Auger Collaborations.

11

Time (100 ns)0 100 200 300 400 500 600 700 800

/ (1

00 n

s)p.

e.N

0

50

100

150

200

250

300

350Data

Simulation

Time (100 ns)0 100 200 300 400 500 600 700 800

/ (1

00 n

s)p.

e.N

-20

0

20

40

60

80

Vertical Laser~1019.3 eV

Cosmic Ray~1018.0 eV

Astroparticle Physics 74 (2016) 64-72, arXiv: 1504.00692(E (eV))

10log

17 17.5 18 18.5 19 19.5 20

Impa

ct p

aram

eter

[km

]

1

10

210Preliminary

Detect

able

Figure 14: Distribution of the impact parameter as a function of the primary energy recon-

structed by TA for shower candidates detected by the FAST prototype. The line indicates

the maximum detectable distance by the FAST prototype (not fitted).

20

http://arxiv.org/abs/1504.00692http://arxiv.org/abs/1504.00692http://arxiv.org/abs/1504.00692

1

FAST - today

Accepted for publication in Astroparticle Physics

Full-scale FAST Prototype

12

Confirmed milestones by EUSO-TA Telescope

Stable operation under high night sky backgrounds.

UHECR detection.

Next milestones by new full-scale FAST prototype

Establish the FAST sensitivity.

Detect a shower profile including Xmax with FAST

FAST meeting in December 2015 (Olomouc, Czech Republic)

FAST - progress in design and construction

UV Plexiglass Segmented primary mirror 8 inch PMT camera (2 x 2)

1m2 aperture FOV = 25x 25

variable tilt

Joint Laboratory of Optics Olomouc Malargue November 2015 3

Prototype - October 2015

15

45

13Joint Laboratory of Optics in Olomouc, Czech Republic

Full-scale FAST Prototype

Ray-Trace Simulation

14420mm x 420 mm

The spherical surface on PMT has complicated point spread function.

We need to calculation efficiency of optics.

It will be used in the offline analysis after data-taking is started.

Focal plane Bottom plane

UV Band-pass Filter

15

UV band pass filter used in

MAGIC

http://arxiv.org/pdf/1509.02048v2.pdf

Using UV-pass filters for bright Moon observations with MAGIC D. Guberman

Wavelenght [nm]300 350 400 450 500 550 600

Ph

oto

n f

lux

[a.u

.]

0

1

2

3

4

5

6

7

8

9

10

Filte

r tr

an

sm

issio

n

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1Direct Moonlight

Diffuse Moonlight

Cherenkov light

Filter transmission

Figure 1: The blue curve shows the typical Cherenkov light spectrum for a vertical shower initiated by aTeV g-ray, detected at 2200 m a.s.l.[7]. The black solid curve shows the shape of direct moonlight spectrum.The dashed black curve, the spectrum from diffuse moonlight. The three curves are scaled by an arbitrarynormalization factor. The filters transmission curve is plotted in red.

ing close to the moon, Mie-scattering of moonlight dominates and its intensity is higher at higherwavelengths (direct moonlight). The actual shape of the spectrum depends on the aerosol contentand distribution and the zenith angle of the Moon. The diffuse and direct moonlight spectra canboth be obtained by folding the solar spectrum with the Albedo of the Moon. This was done usingthe code SMARTS[9, 10] and is shown in figure 1.

The spectrum of Cherenkov light of showers depends mainly on the altitude of the showermaximum, but also on the nature of the incident particle (whether is a g-ray or a hadron) and itsenergy. For a vertical shower initiated by a TeV g-ray, detected at 2200 m a.s.l, it peaks at 330nm, as shown in figure 1. Taking all into account, we selected commercial inexpensive UV-passfilters produced by Subei (model ZWB3) with a thickness of 3mm and a wavelength cut at 420 nm.Its transmission curve was measured and is also shown in figure 1. These filters transmit 45% ofCherenkov light and 20% direct moonlight.

The filters were bought in tiles of 20 30 cm2, and mounted on a light-weight frame. Thisframe consists on an outer aluminium ring that is screwed to the PMT camera and steel 66 mm2

section ribs that are placed between the filter tiles (see figure 2). The filter tiles are fixed to the ribsby plastic pieces and the space between tiles and ribs is filled with silicone. This gives mechanicalstability to the system and prevents light leaks. Two people can mount or dismount the filters in thePMT camera in about 15 minutes.

3

Using UV-pass filters for bright Moon observations with MAGIC D. Guberman

Figure 2: On the left, the filters installed in the camera of one of the MAGIC telescopes. On the right, theframe design that holds the filters. The outer Al ring is screwed to the camera. Filter tiles are held by plasticpieces to steel 66 mm2 section ribs.

3. Data sample and analysis procedure

After data quality selection a total of almost 15 observation hours of Crab Nebula with the UV-pass filters were recorded. The data were taken in the standard L1-L3 trigger condition[3], in theso-called wobble mode[8], with a standard wobble offset of 0.4. All the data analysed correspondto zenith angles lower than 35.

The data was divided into four samples with different NSB conditions and it is summarizedin table 1. The brightness of the sky in each situation is expressed in units of Dark NSB. Thetwo samples of highest NSB include situations in which observations without filters are currentlyimpossible in MAGIC. The mean current measured (DC) in one of the telescopes (MAGIC 1) isalso shown in table 1 and compared to the expected one under the same brightness conditions,but without filters (Eq. DC). The ratio between both of them depends on how close to the Moonthe telescopes are pointing: the background transmission is higher far from the Moon where thediffuse moonlight regime dominates. Close to the Moon the measured DCs with filters can be 5times lower than the expected one without filters, which is consistent with a moonlight transmissionof 20%.

To analyse the data and to evaluate the energy threshold, Monte Carlo (MC) simulations areneeded. The MC for standard analysis in MAGIC (without filters and in dark conditions) wastuned to include the filters transmission, the shadowing in some pixels that is produced by theribs of the frame and the increased NSB. With these modified MC simulations, the data has beenanalysed using the standard MAGIC analysis and reconstructions software, MARS[2, 12]. Due tothe relatively high brightness of the sky, the image cleaning settings for each sample were modifiedwith respect to the standard ones[1].

4

http://arxiv.org/pdf/1509.02048v2.pdfhttp://arxiv.org/pdf/1509.02048v2.pdf

15

FAST components

UV PMMA windowin octagonal aperture

4 PMTscamera8 inch

UV filterglass

cover = black shroud

DUST and STRAY LIGHT protection

cabling

electronics

mirrors4

Building - ground plan required dimensions

Cca

3000

mm

Cca 3500 mm

600

mm

FOV

5Cc

a 30

00 m

m

Cca 3500 mm

FOV

Building height elevation 15required dimensions

Cca 1000 mm

Design of Hut and Shutter

16

8

shutter like sectional garrage doors

closed

open

roof window

Possible solution of building40

00 m

mC

ca 3

000

mm

closed

open

Adjustable elevation 15 or 45, like HEAT and TALE, to enlarge the FoV of the current FD.

Robust design for maintenance free and stand-alone observation.

Easy to Change Elevation

17

FAST Prototype in February 2016

18

FAST Hut and Shutter

!!"#$%&'&($)*+,-./($-01!('23$#4$)5642"3.7"582+

!"#$%&$'()*+,$#%-.

!ELS

Black Rock Mesa FD Station

2012118 Many activities, EUSO-TA, Radio

FAST!!"#$%&'&($)*+,-./($-01!('23$#4$)5642"3.7"582+

!"#$%&$'()*+,$#%-.

!

We will plan to install the full-scale FAST telescope on June 2016.

Possible Application of FAST Prototype

20

1. Introduction

The hybrid detector of the Pierre Auger Observatory [1] consists of 1600surface stations water Cherenkov tanks and their associated electronics and24 air fluorescence telescopes. The Observatory is located outside the city ofMalargue, Argentina (69 W, 35 S, 1400 m a.s.l.) and the detector layout isshown in Fig. 1. Details of the construction, deployment and maintenance ofthe array of surface detectors are described elsewhere [2]. In this paper we willconcentrate on details of the fluorescence detector and its performance.

Figure 1: Status of the Pierre Auger Observatory as of March 2009. Gray dots show thepositions of surface detector stations, lighter gray shades indicate deployed detectors, whiledark gray defines empty positions. Light gray segments indicate the fields of view of 24fluorescence telescopes which are located in four buildings on the perimeter of the surfacearray. Also shown is a partially completed infill array near the Coihueco station and theposition of the Central Laser Facility (CLF, indicated by a white square). The descriptionof the CLF and also the description of all other atmospheric monitoring instruments of thePierre Auger Observatory is available in [3].

The detection of ultra-high energy (! 1018 eV) cosmic rays using nitrogenfluorescence emission induced by extensive air showers is a well establishedtechnique, used previously by the Flys Eye [4] and HiRes [5] experiments. It isused also for the Telescope Array [6] project that is currently under construction,and it has been proposed for the satellite-based EUSO and OWL projects.

Charged particles generated during the development of extensive air showersexcite atmospheric nitrogen molecules, and these molecules then emit fluores-cence light in the 300 430 nm range. The number of emitted fluorescencephotons is proportional to the energy deposited in the atmosphere due toelectromagnetic energy losses by the charged particles. By measuring the rate

7

a r t i c l e i n f o

Article history:Received 25 December 2011Received in revised form25 May 2012Accepted 25 May 2012Available online 2 June 2012

Keywords:Ultra-high energy cosmic raysTelescope Array experimentExtensive air shower array

a b s t r a c t

The Telescope Array (TA) experiment, located in the western desert of Utah, USA, is designed for theobservation of extensive air showers from extremely high energy cosmic rays. The experiment has asurface detector array surrounded by three fluorescence detectors to enable simultaneous detection ofshower particles at ground level and fluorescence photons along the shower track. The TA surfacedetectors and fluorescence detectors started full hybrid observation in March, 2008. In this article wedescribe the design and technical features of the TA surface detector.

& 2012 Elsevier B.V. All rights reserved.

1. Introduction

The main aim of the Telescope Array (TA) experiment [1] is toexplore the origin of ultra high energy cosmic rays (UHECR) usingtheir energy spectrum, composition and anisotropy. There are twomajor methods of observation for detecting cosmic rays in theenergy region above 1017.5 eV. One method which was used at theHigh Resolution Flys Eye (HiRes) experiment is to detect airfluorescence light along air shower track using fluorescencedetectors. The other method, adopted by the AGASA experiment,is to detect air shower particles at ground level using surfacedetectors deployed over a wide area (! 100 km2).

The AGASA experiment reported that there were 11 eventsabove 1020 eV in the energy spectrum [2,3]. However, theexistence of the GZK cutoff [4,5] was reported by the HiRes

experiment [6]. The Pierre Auger experiment confirmed thesuppression on the cosmic ray flux at energy above 4"1019 eV[7] using an energy scale obtained by fluorescence light tele-scopes (FD). The contradiction between results from fluorescencedetectors and those from surface detector arrays (SD) remains tobe investigated by having independent energy scales usingboth techniques. Hybrid observations with SD and FD enableus to compare both energy scales. Information about core locationand impact timing from SD observation improves accuracy ofreconstruction of FD observations. Observations with surfacedetectors have a nearly 100% duty cycle, which is an advantageespecially for studies of anisotropy. Correlations between arrivaldirections of cosmic rays and astronomical objects in this energyregion should give a key to exploring the origin of UHECR [8] andtheir propagation in the galactic magnetic field.

Fig. 1. Layout of the Telescope Array in Utah, USA. Squares denote 507 SDs. There are three subarrays controlled by three communication towers denoted by triangles. Thethree star symbols denote the FD stations.

T. Abu-Zayyad et al. / Nuclear Instruments and Methods in Physics Research A 689 (2012) 879788

Pierre Auger Collaboration, NIM-A (2010) Telescope Array Collaboration NIM-A (2012)

Identical simplified FD

Telescope Array Experiment

Pierre Auger Observatory

log(E(eV))18 18.2 18.4 18.6 18.8 19 19.2 19.4 19.6

Effic

ienc

y

0

0.2

0.4

0.6

0.8

1 ProtonIron

log(E(eV))18 18.2 18.4 18.6 18.8 19 19.2 19.4 19.6

Ener

gy R

esol

utio

n [%

]

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 R

esol

utio

n [g

/cm

max

X 0

20

40

60

80

100

Proton

Iron

Energy

Xmax

Install FAST at Auger and TA for a cross calibration.

Profile reconstruction with geometry given by SD (smearing gaussian width of 1 in direction, 100 m in core location).

Energy: 10%, Xmax : 35 g/cm2 at 1019.5 eV

Independent cross-check of Energy and Xmax scale between Auger and TA

(E (eV))10

log17.5 18 18.5 19 19.5 20 20.5

)-1 s

-1 sr

-2 m2

(eV

24/1

03

E

Flux

-110

1

10Preliminary

TA ICRC 2015

Auger ICRC 2015

Summary and Future Plans

21

Fluorescence detector Array of Single-pixel Telescopes (FAST)

Deploy the economical fluorescence detector array.

Detect UHECRs and neutral particles.

This concept of single-pixel telescope was confirmed by the field measurements using the EUSO-TA optics.

Published in Astroparticle Physics 74 (2016) 64-72

The full-scale FAST prototype is being constructed, and almost ready to ship to Utah.

We plan to install in June 2016.

FAST Webpage

22http://www.fast-project.org

http://www.fast-project.orghttp://www.fast-project.org