The Future of
Very High-Energy Astrophysics
Rene A. Ong (UCLA and ICRR )ICRR Seminar
Seminar, 28 September 2016

Outline
 Scientific & Technical Motivation
Science Overview – VHE gamma-ray
gamma ray sky
Three selected science topics in brief
Experimental TechniquePl
Planning
i for
f the
th F
Futuret
Æ CTA

 Cherenkov Telescope Array (CTA) Concept
Science Drivers Æ requirements
CTA Design & Performance Æ Scientific Capabilities

 CTA Implementation & Status
Implementation: design and prototype telescopes
Present status (2016): status of sites, timeline, etc.
Key Science Projects (KSPs) – Core science – a few examples

 SummaryVery High Energy (VHE) Astrophysics
Highly Non-Thermal
Sourcep
Jet
Active Galactic
Nucleus (AGN)

e

p

EeV
Cosmic Raysπγγ-rays provide, by far, themost direct information

ν

GeV/TeVγ−raysPeV
P V
Neutrinos

VHE γ-ray Sky c1997
4 sources

VHE γ-ray Sky c2005
13 sources

VHE γ-ray Sky c2016~160 sources , covering wide range of types

tevcat.uchicago.edu

Detailed source information: Spectra, Images, Variability, MWL …

TeV + GeV γ-ray Sky c2015~160 sources , covering wide range of types

tevcat.uchicago.edu

Detailed source information: Spectra, Images, Variability, MWL …
+ FERMI-LAT map

VHE
Astronomyy Comes of Ageg
TeV Astronomyy•Dominant e
expectation
pectation (pre(pre-1990)
1990)– Will find the “cosmic ray” accelerators – probably SNRs•

Reality (~2016)– Astonishing variety of TeV* emitters• Within the Milky Way– Supernova remnants– Bombarded molecularmolec lar clouds
clo ds– Stellar binaries - colliding wind & X-ray– Massive stellar clusters– Pulsars
u sa s anda d pulsar
pu sa windd nebulae
ebu ae– Supermassive black hole Sgr A*• Extragalactic– Starburst galaxies– MW satellites– Radio galaxies– Flat-spectrum radio quasars– ‘BL
BL LacLac’ objects– Gamma-ray Bursts*0.05-50 TeV

CosmicPti lParticle
Accelerators

Three Selected Science Topics

 Supernova remnants & origin of cosmic rays
 AGN and intergalactic radiation fields
 Galactic Center & Dark Matter

Supernova Remnants

SN 1006
Blue: X-ray
Yellow: Optical
Red: Radio(Credit:X-ray:
NASA/CXC/Rutgers/G.CassamChenai, J.Hughes et al.; Radio:
NRAO/AUI/NSF/GBT/VLA/Dyer,
Maddalena & Cornwell; Optical:
Middlebury College/F.Winkler,
NOAO/AURA/NSF/CTIO Schmidt& DSS)

TeV g
gamma raysy0.4oSupernova Remnants (SNRs)“Standard Model” for high-energy
cosmic rays
Expanding shell of SNR & shock
front sweeps up ISM material.



Acceleration of particles via
diffusive shock acceleration.

Can supply and replenish CR’s if
ε ~ 5-10%.

HESS

RXJ 1713-3946
Age = 1600y
D = ~1 kpc

VERITAS

VERITAS

Good model … is it right ?
CTA will:
discover many SNRs
SNRs, including
perhaps a few PeVatrons, andcharacterize them (morphology,
SED etc.)
SED,
etc ) much better thanpresent-day instruments.

IC 443Age ~ 30ky
D ~ 0.8kpc

IC 443

WISE – 22, 12, 4.6 μm

Active galactic nuclei
and their jets
Radio

1o
Cen-A
Nearest AGN, d ~ 4 Mpc
Radio lobes 3-4o, ~300 kpC

Active galactic nuclei
and their jets

Radio
Radio

kpc
“I
“Inner
jet”
j t”

1o
Cen-A
Nearest AGN, d ~ 4 Mpc
Radio lobes 3-4o, ~300 kpC

Active galactic nuclei
and their jets

Radio
Radio

TeV energies
HESS, ApJL
695 (2009) L40

1o
Cen-A
Nearest AGN, d ~ 4 Mpc
Radio lobes 3-4o, ~300 kpC

kpc“I“Innerjet”
j t”

AGN: Extreme
Variability
AGN: The
most violent“Blazars”: AGN with jets pointed towards us
strongg VHE emitters
PKS 2155-304
2155 304 flflare
arXiv:0706.0797

isotropic luminosity 1046 erg/s(luminosity of Milky Way: 1044 erg/s)

TeV
γ-ray
Flux

z = 0.116

2 minute bins

➜ limits on energy-dependenceof speed of light

Time [minutes]

VHE γ-rays as Cosmological Probes
Extragalactic Background
Light (EBL):• OIR diffuse backgroundproduced by star-formation
throughout history of universe.
• γγ interaction probes EBL
density, uniformity, evolution.
• A way to measure/constrain
tiny intergalactic magnetic
field (IGMF):
B ~ 10-10 - 10-18 G
1 TeV

1 PeV

EnergyGalactic Center
Infrared

TeV γ-rays
VERITAS•

Jim
BuckleyGhez et al., 2012
1” x 1”

GeV & TeV emission is:•••

intense & non-thermal
totally unexpected
not understood !

A, Archer et al.
VERITAS Coll.
(2015)
1o x 2oDark Matter Detection
SM: b,, W+, Z,, τ+, …
Primary channels_

DM

SM: b, W-, Z, τ-,…

Hadronnisation
and/or d
decay

DM

γ−ray
γ y Signals
gγ, e+, p, ν, …
Final statesγ, e-, p, ν, …

Galactic CenterLine signals ?

Satellites“Universal” Spectrump
1.4 TeV Higgsino(Bergstrom)

Extragalactic

Halo

Ultimate goal: Dark Matter Astronomy

DM simulation(Pieri et al., 2011)

Exploring the nonnon-thermal Universe “ASTRO”
SNRs
Pulsars/PWN

Binaries

Starbursts
AGN
SMBH
accretion,jets

NSdynamowinds
Jets, winds?

ShocksFermi Mech.

SN activity
Cosmic rays

GRBs

VHE γ-rays
γ raysUnknowns(Gal Center)

Dark MatterCosmologicalgFields

PBHs, QGrav

Probing New Physics at GeV/
GeV/TeV scale “PARTICLE”

Summary of Key Science Questions
Bottom line: GeV and TeV gamma-ray sources are ubiquitous in
the universe and probe extreme particle acceleration
acceleration, and thesubsequent particle interactions and propagation.
1. How are the bulk of cosmic ray particles accelerated in our Galaxy and beyond?
(one of the oldest surviving questions of astrophysics)
2. Can we understand the physics of jets, shocks & winds in the variety of sources wesee, including pulsars, binaries, AGN, starbursts, and GRBs?
3. How do black holes of all sizes efficiently particles? How are the structures (e.g. jets)
formed and how is the accretion energy harnessed?
4 Wh
4.
Whatt ddo high-energy
hi h
gamma rays tellt ll us aboutb t ththe start fformation
ti history
hi t
off theth
Universe, intergalactic radiation fields, and the fundamental laws of physics?
5. What is the nature of dark matter and can we map its distribution through its particle
i tinteractions?
ti?
6. What new unexpected phenomena will be revealed by exploring the non-thermal
Universe?
Bonus science: optical interferometry, cosmic-ray physics, OSETI, etc.

Experimental Technique&
Planning for the FutureFermi Large Area Telescope (LAT)
Anti-Coincidence
ShieldSi Strip Tracker

30 MeV-300 GeV

Calorimeter~ 1 m2 2.5 sr
ExcellentE
ll t survey
instrument

Beyond 100 GeVSteeply falling spectrum:x10 in Energy Æ divide by 100-500 in flux
• Large effective area needed to get detectable signals at VHE• Natural detector: the atmosphereImaging
atmospheric
Cherenkov
technique

Image incameraPulse is ~few ns duration
Effective area =Cherenkov light pool~105 m2 !

Whipple 10m
γ-ray Telescope(1968-2011)

10m
C
Camera• Pioneered use of Imaging
g g• Made first source detection.
(Crab Nebula in ~90 hours)

gamma ray?
g
y

γ-ray

cosmic ray

cosmic ray?

Page 25

Imaging
atmospheric
Cherenkov
arraysImage incameraPulse is ~few ns duration
Effective area =Cherenkov light pool~105 m2 !

FermiVHE Telescopes (2016)
MAGIC
VERITAS
ARGO-YBJVERITAS
ARGO / YBJ

HAWCVERITAS
HAWC

HESS
HESS
HESS

IceCubeHESSFrom current arrays to CTA
Light pool radiusR ≈ 100-150m≈ typicalt i l telescopet lSpacingSi

Sweet spot for best
triggering &reconstruction…
most showers miss it!

✓Large detection Area
✓More Images per shower✓Lower trigger thresholdHOW TO DO BETTER WITH IACT ARRAYS?
➡ More events,, more photonsp‣Better spectra, images, fainter sources✓Larger light collecting area
✓Better reconstructed

events‣ Better measurement of air showerand hence primary gammas✓Improved angular resolution✓Improved background rejection power➡ More telescopes!
Simulation:
Superimposed images from
8 cameras

Planning for the Future
What we know, based on H.E.S.S., MAGIC, VERITAS:
G
Great
scientificf potential exists in the VHE domain¾ Expect many more sources & deeper probes for new physics

IACT Technique is very powerful¾ Have not yet reached its full potential Æ large Cherenkov array

Exciting science in both Hemispheres¾ Argues for an array in both S and N

Open Observatory Æ Substantial reward¾ OpenOdata/access,d t /MWL connectionsti
tot gett theth bestb t scienceiInternational Partnerships required by scale/scope¾ Project must develop the instrument and the observatory

Science Drivers

NASA

10% Energy
Resolution→ lines, features

Science Drivers

Rapid Slewing
in 20 seconds→ transientsNASA

10% Energy
Resolution→ lines, features

Science Drivers

Energies down
to 20 GeV
→ Cosmology++

Rapid Slewing
in 20 seconds→ transientsNASA

10% Energy
Resolution→ lines, features

Science Drivers

Energies down
to 20 GeV
→ Cosmology++

Rapid Slewing
in 20 seconds→ transientsNASA

10% Energy
Resolution→ lines, features

Science Drivers

Energies down
to 20 GeV

10 x Sensitivity,
Large Collection
Area→ all topics→ Cosmology++

Rapid Slewing
in 20 seconds→ transientsNASA

10% Energy
Resolution→ lines, features

Science Drivers

Energies down
to 20 GeV
→ Cosmology++

10 x Sensitivity,
Large Collection
Area→ all topics

Energies up to
300 TeV→ Pevatrons

Rapid Slewing
in 20 seconds→ transientsNASA

10% Energy
Resolution→ lines, features

Science Drivers

Energies down
to 20 GeV
→ Cosmology++

10 x Sensitivity,
Large Collection
Area→ all topics

Energies up to
300 TeV→ Pevatrons

Rapid Slewing
in 20 seconds

8o Field of View
→ surveys,
surveysextended objects→ transientsNASA

10% Energy
Resolution→ lines, features

Science Drivers

Energies down
to 20 GeV
→ Cosmology++

10 x Sensitivity,
Large Collection
Area→ all topics

Energies up to
300 TeV→ Pevatrons

Rapid Slewing
in 20 seconds

8o Field of View
→ surveys,
surveysextended objects→ transientsNASA

10% Energy
Resolution

Few ‘ Angularg
Resolution→ lines, features→ morphology

Science Drivers

CTA Design (S array)
Science Optimization under budget constraints

Low energies
Energy threshold 20-30 GeV
23 m diameter4 ttelescopesl(LST’s)Medium energies
100 GeV – 10 TeV
9.5 to 12 m diameter
25 single-mirror telescopes
up to 24 dual-mirror telescopes(MST’s/SCTs)(MSTs/SCTs)Hi h energiesHighi
10 km2 area at few TeV
3 to 4m diameter
70 telescopes(SST’s)Differential Flux Sensitivity
Hinton & FunkarXiv:1205.0832

F
Fermi
i

HESS / VERITAS

Major sensitivity improvement & wider energy range
Æ Factor of ~x10 increase in source population

CTA in Context
VisibleVERITAS /CTA

Adapted from T. Takahashi

Galactic
Discovery
Reach

Current Galactic
VHE sources(with distanceestimates)

HESS/
VERITAS

CTA

Survey speed:x300
300 ffaster thanh HESS5°8°

Angular Resolution
8° CTA FoV

HESS

Fermi

CTA
(3 TeV)(3 TeV)(10 GeV)

HESS centroid
error

CTA
centroiderror

Example: Cen A

0.1°
T i l HESS
TypicalResolution

2‘
CTA > 1 TeV
45

45

Transient Capability (< 100 GeV)
S. Inoue et al.,arXiv:1301.3014
Hinton & FunkarXiv:1205.0832

GRB (z=4.3) Light curve
Huge potential for short
short-timescale
timescale phenomena(GRB’s, AGN, Micro-quasars, etc.)

CTA Implementation & Status

CTA Consortium
CTA is being developed by the CTA Consortium:(full version shows pie chart with Japan FTE highlighted)

32 countries, ~1300 scientists, ~200 institutes, ~440 FTE

Status of Sites

The Future of Research on Cosmic
Gamma Rays (J. Knödlseder)

Status of Sites

NEWS: 19 Sept 2016
IAC-CTA agreementgsignedThe Future of Research on Cosmic
Gamma Rays (J. Knödlseder)

CTA South Array
4 LSTs
LSTs, 25 MSTs
MSTs, 70 SSTs

SST

MST

LST

2 km

LargeT l
Telescope
(LS

Large
Telescope(LST)

23 m diameter / f = 28m
390 m2 dish area
1.5 m mirror facets
4.5
45o field of view
0.1o pixels
Camera ∅ over 2 m
Carbon-fiber structurefor 20 s positioning
Active mirror control
4 LSTs on South site
4 LSTs on North site
Prototype construction
Underway (La Palma)

Major contribution
from JAPANMedium Telescope (MST)

100m2 mirror dish area
16 m focal length
1.2 m mirror facets
8o field of view
~2000 x 0.18o pixels
25 MST
2
MSTs on SSouthh sitei
15 MSTs on North site
Prototype at DESY (Berlin)

MST Integrated Camera

100m2 mirror dish area
16 m focal length
1.2 m mirror facets
8o field of view
~2000 x 0.18o pixels
25 MST
2
MSTs on SSouthh sitei
15 MSTs on North site
Prototype at DESY (Berlin)Dual-Mirror MST• Schwarzschild-Couder design(V. Vassiliev et al.)• 9.7m
9 7m primaryprimary, 55.4m
4m secondary• 11328 x 0.07o Si-PMT pixels• 8o field-of-view• Prototype under construction:
Whipple Obs. (Arizona, USA)

http://cta-psct.physics.ucla.edu/

Small Sized Telescopes (SSTs)• 3 different prototype designs• 2 designs use two-mirror approaches (Schwarzschild-Couder design)• All use Si-PMT photosensors• 7-9 m2 mirror area, FOV of 9o

SST 1M
SST-1M
Krakow, Poland

SST 2M ASTRI
SST-2M
Mt. Etna, Italy

SST 2M GCT
SST-2M
Meudon, France
Contribution from Japan

Japanese Contributions to CTA
LSTMajor Contributions+
SoftwareSimulations
Science …
Front-end
electronics (LST)Light concentrator(LST)
IbarakiKyoto
ICRR
SST GCT
SST-GCT

Mirror (LST)

SiPM (SST)
NagoyaKonan

H. Tajima

PMT (LST)

Front-end (SST/electronics SCT)CTA Phases
SPRR

International
Convention

PDR CDR

1 Design
Construction Phase

2 Pre-Construction
NOW

3 Pre-Production
Advance
Deployment

PPRRs
& MoU

•
•
•
•
•

4 Production

5 Operations

Signed MoU for construction and site agreements in 2016
Site preparations start in 2016 (N) and 2017 (S)Construction period of 4-5 years
Initial science with partial arrays possible from 2018 (N) and 2019 (S)Note: LSTs in N completed on earlier time scale

CTA: An Open Observatory

All data on public archive after ~1 yr proprietary period

Important MWL Synergies

Caveat: Observatory timelines are very uncertain; this represents a notional
picture based on available information

Key Science Projects (KSPs)
Transients

Dark Matter
Programme

GalaxyClusters

ExGal
SSurveySta FormingStarog
Systems

AGN
LMC
SurveyGalacticPl
Plane
S
SurveyPeVatrons
GalacticGl ti
CentreCTA CDR - SCIENCE, 24 June 201561

Galactic Plane Survey (GPS)J. Knödlseder &CTA Consortium

SNRs / PeVatrons: Discovered in GPS Æ deep follow-up observations

Dark Matter Reach
M. Wood et al.
arXiv:1305.0302

Sensitivity below thermal relic in TeV mass range- critical reach, not achieved by direct detectors or LHC

CONCLUSIONSWith many discoveries, VHE γ-rays are now a well-recognizedastrophysical discipline & part of growing multi-messenger
multi messenger
science.



VHE photons explore non-thermal universe and aspects off dfundamentalt l physics
h i

Outstanding science potential & power of atmosphericqÆ CTA
Cherenkov technique Cherenkov Telescope Array (CTA)
Outstanding sensitivity & resolution over wide energy range
Far-reaching key science program
Open observatory with data released to public
CTA requires a broad partnership of countries andcommunities – with a major contribution from Japan

Summary We’ve learned a lot from previous/present experiments
With many discoveries, VHE γ-rays are now a well-recognizedastrophysical discipline
Outstanding science potential & the power of the atmospheric
Cherenkov technique Æ CTA

 Cherenkov Telescope Array (CTA)
Outstanding sensitivity & resolution over wide energy range
Far-reaching key science program
Open observatory with all data released to public
US contribution focused on novel
novel, high-resolution SC telescope
CTA requires a broad partnership of countries and communities
 IIn nextt decade,dd CTA will
ill startt t tot provide
id high-quality
hi h
lit d
data,
t nott seen
with any HE/VHE technique, but there is still a great deal to do !

BACKUPCTA Main Scientific Themes
Cosmic Particle Acceleration– How and where are particles accelerated?
– How do they propagate?
– What is their impact on the environment?

Probing Extreme Environments– Processes close to neutron stars and black holes– Processes in relativistic jets, winds and explosions– Exploring cosmic voids

Physics frontiers – beyond the Standard Model– What is the nature of Dark Matter? How is it distributed?
– Is the speed of light a constant for high-energy photons?
– Do axion-like particles exist?
More information on Astroparticle Physics, Vol. 43, 1-356 (2013) & CTA Contributions to the 2015 ICRC Conference[arXiv:1508.05894]

The HE Milky Way
H E S S (TeV)
H.E.S.S.

Fermi-LAT (GeV)

Extended sources, size typically few 0.1o
few 10 pc

Courtesy of W. HofmannIs the Universe too Transparent ?

Horns & Meyer
arXiv:1201.471

Axion conversion ??
Sanchez-Conde et al.,arXiv:0905.3270

Dark Matter Results
γ-ray DM limits

But …
T. Daylanyet alarXiv:1402.6703

GeV excess in GC
No signal (yet)R A Ong,
R.A.
Ong Nobel Symposium 154

 Limits approaching the thermal reliccross section.
 Gamma-ray instruments probe highmass region not easily accessible byother techniques very significant
significant.
 seen by multiple authors.
 consistent with DM profile and
30 40 GeV mass.
30-40
mass
 Complicated region with multiple
astrophysical components.

BACKUPBACKUPBACKUPBACKUPBACKUP

Flux Sensitivity (Crab units)
For detection in each 0.2-decade energy binbackground andsystematics limited

rate (=area) limited

background limited

SST

LST
MST

CTA Observing
g TimePI-ledProjects:“GO time”
or“Open Time”

CTA
ObservingTime

Key Science
Projects

PI-ledPI
led
Projects:“GO time”
or“Open Time”

M b
MemberTime
forMembers
andAssociate
Members

DDT
Host
reservedtime

also open for
NonMembers
ESO Council – CTA Science, June 2016

Scientificexcellence as
criterion for
selectionLong term balance
betweenparticipating
countries to bemonitored

All data
accessible
ibl onpublic archiveafter 1 year

77Full Sky Coverage
North + SouthSouth>60o zenith
45o-60o30o-45oNorthAngular Resolution
CTA RESOLUTION~ few arc-mins over most of the E range

Requirement

2 arc-min

CTA
Goal

Angular resolution critical for
Source morphology and identification
Galactic-CenterregionCTA Collection Area
Region where data is
critically needed

Acoll ~107 m2 above 10 TeV
Crucial for:
High-energy spectra, discovery of Pevatrons Æ Origin of CRs

sites to cover full sky
Site Selection
CTA Sites: Two
Candidates
at 20o-35
35o N,
N S

North:Spain
S i – La
L PalmaP l
La Palma (Spain) selected as 1st priority
+30

-30

South:
ESO/Paranal (Chile) selected as 1st priority

sites to cover full sky,Site Selection
CTA Sites: Two
Candidates
latitude 20o-35
35o in N
N, S

USA – Meteor Crater
S i – La
Spain
L Palma
P l+30
Mexico – San Pedro Martir

Namibia – Aar

Argentina –-30 Leoncito
Chile – Armazones

CTA Key Science Projects (KSPs)
Science Questions

DM

KSPs

Nine KSPs + DM Programmedg
are p
proposedpHere, show just a few of the KSPs …

WIMP DM Complementary Approaches

WIMP annihilation
In the cosmos

Indirect Detection

Heavy particle prod.
MET + jets
Weak pair prod.
MET + monojet

LHC P
Productiond ti
WIMP-Nucleon
Elastic scattering

Direct DetectionWIMPs: a More General Framework
D. BauerDB
ett al.,l “Dark“D k Matter
M tt ini theth Coming
C i Decade:Dd Complementary
C
l
t
Paths
P th
to Discovery and Beyond,” White Paper for Snowmass 2013.
Gluon Interactions

preliminary

Quark Interactions

preliminary

LeptonpInteractions

preliminary

1.0 = expected thermal relic cross-section• For gluon/quark interactions, LHC competitive or dominates
at energies below ~few 100 GeV.
• For gluon and lepton interactions, direct expts. are important.
• For quark and lepton interactions, indirect expts are important.

Galactic Plane Survey (GPS)
Entire plane surveyed to < 3.8 mCrab - several 100’s of sources

Galactic Center
Very deep exposurearound SGR A*,
covering central source,
DM halo,halo radio lobes

GPS pointings

Deep exposure in
10o by 10o region,
regionto edge of Gal. bulge,
Covering radio spurs,base of Fermi bubbles,
Kepler SNR

Extragalactic Survey
Survey ~1/4 of sky (adjoining GPS)• Unbiased sample of blazars, log N – log S, extreme blazars, etc.
• Wider coverage of serendipitous events – e.g. GRBs
• Unexpected phenomena – e.g. ULIRGs, Seyferts, dark clumps,

Extragalactic Survey
Blazar luminosity function

Telescope Specifications
SiPM Cameras
3 SST types
LST

MST

SCT

SST

“large”“medium”“medium 2-M”

“small”

Number

4 (S)
4 (N)

25 (S)
15 (N)≤ 24(S and N)

70 (S)

Energy range

20 GeV to
1 TeV

200 GeV to
10 TeV

200 GeV to
10 TeV> few TeV

Effective
mirror area

> 330 m2

> 90 m2> 50 m2> 5 m2

Fi ld off view
Field
i

> 4.4
4 4o

> 7o

> 7o

> 8o

Pixel size
~PSF
PSF θ80< 0.12o< 0.18o< 0.07o< 0.25oPositioning
time

50 s,
20 s goal

90 s,
60 s goal

90 s,
60 s goal

90 s,
60 s goal

Target capitalcost

7.4 M€

1.6 M€< 2.0 M€

500 k€

LA PALMA• Canary
C
IIslands,
l d S
Spain
i
• Observatorio del Roque de los Muchachos• Existing observatory, under management by
Instituto de Astrofisica de Canarias (IAC)• Site of LST prototype & existing MAGIC telescopes

LA PALMA – Possible Layout

ESO/PARANAL• Atacama Desert, Chile• Below Cerro Paranal• Existing observatory, under management by
European Southern Observatory (ESO)• Near a set of existing (VLT) and future (ELT) telescopes

ESO/PARANAL – POSSIBLE
LAYOUT & POWER
South Reference Site Layout

meters
1500

1000

500

LST
0

MST
SST
SCT

-500

-1000

-1500
-1500

-1000

-500

0

500

1000

1500 meters

LST Full Prototype
Elevation drive prototype

Prototype
CameradesignMirror prototype(cold-slump, Sanko)

Area = 1.96
1 96 m2
Mass = 47 kg

MST Cameras and Mirror Control
Prototype automatic
mirror control (AMC)

Flash-ADC + digital trigger + rack electronics(“FlashCAM”)

Capacitor pipeline + analog trigger +fully-contained “drawers” (“NectarCAM”)

Nectar-board
prototypeSST-2M-GCT Camera + Module
Lid

Pointing
LEDs

Enclosure

32
Photosensor
modules
LED
Flasher
U it
Units~0.4 m~45
45 kkg ~450 W

Liquidcooling

Photosensor module

Silicon-PMT Camera

SST-2M -ASTRI Focal Plane
Photon Detection Module
PDM

Each PDM workspy from the others
independently

ASTRI Focal Plane

S11828-3344M1
the ‘Unit’
geometricaldead area

Logical pixel
6.2×6.2mm≡ 0.17°(4 channels)

4×4 Units Æ 1 PDM
56×56mm(64 channels)
37 PDMs Æ Focal Plane
560×560mm(1984 channels)

Observing Schedule (S, Yrs 1-2)

Essentially all KSP
observations completed
in the two years.

Two-Mirror Telescopes
Schwarzschild-Couder (SC) Design
Vassiliev, Fegan, Brousseau
Astropart.Phys.28:10-27,2007

 Reduced plate scale ImprovedI
d PSF
 Uniform PSF across f.o.v.
➜ Low-cost
Low cost small
telescopes with compact
sensors (SST-2M)➜ Higher-performance,
cost-effective, medium
telescope (MST-SCT)(MST SCT)
3 telescope prototypes within CTA are using two mirror designs All make use of Si-PMT cameras.

SCT Prototype Development
Prototype panels forprimary mirror (M1)

Prototype under construction in Arizona
Camera design,design backplane and elements

B k l
Backplane

Individual (64-chan)
Camera module

TARGET-7
ASIC

SCT Æ Superior Imaging
Made possible by Si-PMT’s !
“Baseline”
Baseline
Single-Mirror
Telescope
Images8° fieldfi ld off viewi
0.18° pixels
1,570 channels
Signal:γ-ray Shower
Energy: 1 TeV

Background:
Proton Shower
Energy:gy 3.2 TeV

SCTTwo-Mirror
Telescope
Images8° field of view
0 067° pixels
0.067
11,328 channels

Key Science Projects & GO Programme