GLAST Large Area Telescope:
Gamma-ray Large Area Space Telescope
GLAST Large Area Telescope: LAT Project and the calorimeter Per Carlson KTH Stockholm for the GLAST Collaboration SCINT2001, Chamonix 17-21 September 2001
Gamma-Ray GLAST Large Area Space Telescope
GLAST
International Collaboration ~~ 100 100 collaborators collaborators from from 28 28 institutions institutions
Organizations Organizations with with LAT LAT Hardware Hardware Involvement Involvement TKR CAL ACD
CAL
TKR
Stanford StanfordUniversity University&&Stanford StanfordLinear LinearAccelerator AcceleratorCenter Center NASA Goddard Space Flight Center NASA Goddard Space Flight Center Naval NavalResearch ResearchLaboratory Laboratory University Universityof ofCalifornia Californiaat atSanta SantaCruz Cruz University of Washington University of Washington Commissariat Commissariataal’Energie l’EnergieAtomique, Atomique,Departement Departementd’Astrophysique d’Astrophysique(CEA) (CEA) Institut National de Physique Nuclearie et de Physique des Particules Institut National de Physique Nuclearie et de Physique des Particules(IN2P3): (IN2P3): Ecole EcolePolytechnique, Polytechnique,College Collegede deFrance, France,CENBG CENBG(Bordeaux) (Bordeaux) Hiroshima HiroshimaUniversity University Institute of Space Institute of Spaceand andAstronautical AstronauticalScience, Science,Tokyo Tokyo RIKEN RIKEN Tokyo TokyoInstitute Instituteof ofTechnology Technology Instituto InstitutoNazionale Nazionaledi diFisica FisicaNucleare Nucleare(INFN): (INFN): Pisa, Pisa,Trieste, Trieste,Bari, Bari,Udine, Udine,Perugia, Perugia,Roma Roma
TKR CAL Royal RoyalInstitute Instituteof ofTechnology Technology(KTH), (KTH),Stockholm Stockholm CAL
Structure and Evolution of Universe Quests Extremes of Energy & Matter
Beyond the Big Bang
Black Holes The Lives of Stars
Gamma rays carry a wealth of information: – γ -rays do not interact much at their source: they offer a direct view into Nature’s largest accelerators. – similarly, the Universe is mainly transparent to γ rays: can probe cosmological volumes – conversely, γ -rays readily interact in detectors, with a clear signature – γ− rays are neutral: no complications due to magnetic fields. Point directly back to sources
Energy
Energy versus time for X and Gamma ray detectors 1 TeV
WHIPPLE
HEGRA
CAT
CANGAROO
Super Cangaroo
MILAGRO
HESS
ARGO GRANITE
100 GeV
VERITAS
MAGIC
CELESTE, STACEE, Solar Two
GLAST
10 GeV 1 GeV
AGILE
EGRET
100 MeV 10 MeV
HESSI
COMPTEL
1 MeV 100 KeV
INTEGRAL BATSE OSSE
HETE 2
SIGMA
RXTE
10 KeV
Super AGILE
BeppoSAX
Constellation-X
ASCA
1 KeV Chandra XMM
ROSAT 1992 1994 1996 Aldo Morselli 01/01 http://www.roma2.infn.it/infn/agile/
1998
2000
Year
2002
Swift 2004
XEUS 2006
2008
Aldo Morselli 6/9/99 http://www.roma2.infn.it/infn/agile/
GLAST Science Topics • • • •
• • •
Active Galactic Nuclei Isotropic Diffuse Background Radiation Cosmic Ray Production: – Identify sites and mechanisms Endpoints of Stellar Evolution – Neutron Stars/Pulsars – Black Holes Unidentified Gamma-ray Sources Dark Matter Solar Physics
• DISCOVERY! •
Gamma Ray Bursts
Scientific Heritage: CGROEGRET (E > 100 MeV) 3C279
Cygnus Region
Vela Geming a
Cosmic Ray Interactio ns With ISM
PSR B170644
LM PKS 0208- C 512
Cra PKS b 0528+134
3rd EGRET Source Catalog • 271 sources • 172 sources are unidentified
Diffuse Extra-galactic Background Radiation Is it really isotropic (e.g., produced at an early epoch in intergalactic space) or an integrated flux from a large number of yet unresolved sources? GLAST has higher sensitivity to weak sources, with better angular resolution. GLAST will bring alive the gamma-ray sky!
The origin of the diffuse extragalactic gamma-ray flux is a mystery. Either sources are there for GLAST to resolve (and study!), OR there is a truly diffuse flux from the very early universe.
Active Galactic Nuclei (AGN) Active galaxies produce vast amounts of energy from a very compact central volume. Prevailing idea: powered by accretion onto super-massive black holes (106 - 1010 solar masses). Different phenomenology primarily due to the orientation with respect to us. HST Image of M87 (1994)
Models include energetic (multi-TeV), highly-collimated, relativistic particle jets. High energy γ-rays emitted within a few degrees of jet axis. Mechanisms are speculative; γ-rays offer a direct probe.
Dark matter Rotational curve Dar matter halo
The Thedark darkmatter matterhalo haloisis necessary necessaryin inorder orderto to explain explainthe therotational rotational curve! curve! From Jungman et al, Phys. Rep. 267(1996)195.
Dark matter X-rays from a hot gas in a galaxy cluster An AnX-ray X-rayimage image(purple) (purple)that that shows showshot hotgas gassuperimposed superimposed on onaavisible visiblelight lightimage. image.
The Thegas gasisisso sohot hotso sothat thatthe the visible visiblemass massininthe thegalaxy galaxy cluster clusterisisnot notsufficient sufficienttoto keep keepit. it. ⇒ ⇒Dark Darkmatter! matter!
Candidates for Galactic Dark Matter • Massive Compact Halo Objects (MACHOs) • Low (sub- solar) mass stars. Standard baryonic composition. • Use gravity microlensing to study. • Could possibly account for 25% to 50% of Galactic Dark Matter.
• Neutrinos • Small contribution if atmospheric neutrino results are correct, since mν< 1eV. • Large scale galactic structure hard to reconcile with neutrino dominated dark mat
• Weakly Interacting Massive Particles ( WIMPs) • Non- Standard Model particles, ie: supersymmetric neutralinos • Heavy (> 10GeV) neutrinos from extended gauge theories.
WIMP Dark Matter Annihilations? Extensions to the Standard Model of Particle Physics also provide good candidates for galactic halo dark matter. This would be a totally new form of matter.
X X
Simulated response to 50 GeV side-entering γ’s Number of counts
If true, there may well be observable halo annihilations into monoenergetic gamma rays. q
or γγ or Zγ q “lines”? Energy (GeV)
Just an example of what might be waiting for us to find!
(6S)
Total photon spectrum from the galactic center from χχ ann. • Two-year scanning mode Infinite energy resolution With finite energy resolution
γ lines 50 GeV 300 GeV
Bergstrom et al.
Diffuse gamma ray flux from cosmological χχ ann. EGRET extragalactic diffuse data
In this case broader line due to redshift.
mχ = 86 GeV mχ = 166 GeV Bergstrom et. al. astro-ph/00105048
Best EGRET GRB GRB 940217
GRB Missions CGRO Beppo SAX HETE - II
Swift AGILE GLAST EXIST 1995
2000
2005
2010
2015
EGRET(Spark Chamber) VS. GLAST(Silicon Strip Detector)
EGRET on Compton GRO (1991-2000)
GLAST Large Area Telescope (2006-2015)
Large Area Telescope (LAT) γ Design Overview Instrument 16 towers ⇒ modularity
height/width = 0.4 ⇒ large field-of-view
Tracker Si-strip detectors: total of ~106 ch.
Calorimeter hodoscopic CsI crystal array ⇒ cosmic-ray rejection ⇒ shower leakage correction shower max contained < 100 GeV
Anticoincidence Detector Shield segmented plastic scintillator ⇒ minimize self-veto
e+
Flight Hardware & Spares 16 Tracker Flight Modules + 2 spares 16 Calorimeter Modules + 2 spares 1 Flight Anticoincidence Detector Data Acquisition Electronics + Flight Software
e– 3000 kg, 650 W (allocation) 1.75 m × 1.75 m × 1.0 m 20 MeV – 300 GeV
Calorimeter structure and design
Side panel
AFEE PEM
Closeout plate
CAL structure and design Corner aluminum
Bottom plate : alveolar structure aluminum attached to the Grid.
Carbon Fiber cells in compact geometry
Insert to attach Closeout Plate, AFEE, Side Panel
Crystal Detector Element (Wrapped)
Mylar tape Composite cell 3M film strip
Dual PIN diode
Kapton cable
Elastomer cord
CsI(Tl) ingot at AMCRYS
Light yield as function of position Left PMT, right PMT and average.
Light yield measurements June 2001
Performance Plots
(after all background rejection cuts, being updated)
FOV w/ energy measurement due to favorable aspect ratio
Effects of longitudinal shower profiling
Derived performance parameter: high-latitude point source sensitivity (E>100 MeV), 2 year all-sky survey: 1.6x10-9 cm-2 s-1, a factor > 50 better than EGRET’s
LAT Capabilities • Low deadtime – 8000 cm2 - LAT – 1500 cm2 - EGRET • Large FOV for detecting rare events – >2 sr - LAT – 0.5 sr - EGRET
Expected LAT Performance • 100 - 200 GRBs detected per year • Localization of 1 - 10 arcmin • Afterglows – ~25 afterglows/year
> 30 MeV
– ~ 4 afterglows/year
> 100 MeV
– 75% of afterglows will persist for À 2000 sec
-2 -1 Integral flux (photons cm s )
10
Sensitivity of γ-ray detectors
-7
5 sigma, 50 hours, > 10 events 10
EGRET
-8
AGILE 10
-9
Crab Nebula
GLAST 10
-10
All sensitivities are at 5σ. Cerenkov telescopes sensitivities (Veritas, MAGIC, Whipple, Hess, Celeste, Stacee, Hegra) are for 50 hours of observations. Large field of view detectors sensitivities (AGILE, GLAST, Milagro,ARGO are for 1 year of observation.
CELESTE, STACEE MILAGRO
MAGIC 10
10
-11
ARGO Whipple
-12
VERITAS 10
10
Large field of View experiments Cerenkov detectors in operation Past experiments HEGRA Future experiments
-13
-14
10
-1
10
0
10
1
Aldo Morselli 01/01 http://www.roma2.infn.it/infn/agile/
10
2
10
3
MAGIC sensitivity based on the availability of high efficiency PMT’s
HESS 10
Photon Energy (GeV)
4
Sky coverage of “all sky “ and Cerenkov telescopes in 2002 CAT HEGRA Magic
Milagro Whipple
AGILE
Cerenkov telescope “all sky” monitors
Conclusions Ð
GLAST will be an important step in gamma ray astronomy ( ~10 000 sources compared to ~ 200 of EGRET)
Ð
A partnership between High Energy Physics and γ−ray Astrophysics
Ð
Beam test and software development well on the way
Ð
Wide range of possible answers/discoveries, including possible dark matter detection
Ð
Gold era for multiwavelenght studies Be prepared, 2006 is near !
GLAST Large Area Telescope: LAT Project and the calorimeter Per Carlson KTH Stockholm for the GLAST Collaboration SCINT2001, Chamonix 17-21 September 2001
Gamma-Ray GLAST Large Area Space Telescope
GLAST
International Collaboration ~~ 100 100 collaborators collaborators from from 28 28 institutions institutions
Organizations Organizations with with LAT LAT Hardware Hardware Involvement Involvement TKR CAL ACD
CAL
TKR
Stanford StanfordUniversity University&&Stanford StanfordLinear LinearAccelerator AcceleratorCenter Center NASA Goddard Space Flight Center NASA Goddard Space Flight Center Naval NavalResearch ResearchLaboratory Laboratory University Universityof ofCalifornia Californiaat atSanta SantaCruz Cruz University of Washington University of Washington Commissariat Commissariataal’Energie l’EnergieAtomique, Atomique,Departement Departementd’Astrophysique d’Astrophysique(CEA) (CEA) Institut National de Physique Nuclearie et de Physique des Particules Institut National de Physique Nuclearie et de Physique des Particules(IN2P3): (IN2P3): Ecole EcolePolytechnique, Polytechnique,College Collegede deFrance, France,CENBG CENBG(Bordeaux) (Bordeaux) Hiroshima HiroshimaUniversity University Institute of Space Institute of Spaceand andAstronautical AstronauticalScience, Science,Tokyo Tokyo RIKEN RIKEN Tokyo TokyoInstitute Instituteof ofTechnology Technology Instituto InstitutoNazionale Nazionaledi diFisica FisicaNucleare Nucleare(INFN): (INFN): Pisa, Pisa,Trieste, Trieste,Bari, Bari,Udine, Udine,Perugia, Perugia,Roma Roma
TKR CAL Royal RoyalInstitute Instituteof ofTechnology Technology(KTH), (KTH),Stockholm Stockholm CAL
Structure and Evolution of Universe Quests Extremes of Energy & Matter
Beyond the Big Bang
Black Holes The Lives of Stars
Gamma rays carry a wealth of information: – γ -rays do not interact much at their source: they offer a direct view into Nature’s largest accelerators. – similarly, the Universe is mainly transparent to γ rays: can probe cosmological volumes – conversely, γ -rays readily interact in detectors, with a clear signature – γ− rays are neutral: no complications due to magnetic fields. Point directly back to sources
Energy
Energy versus time for X and Gamma ray detectors 1 TeV
WHIPPLE
HEGRA
CAT
CANGAROO
Super Cangaroo
MILAGRO
HESS
ARGO GRANITE
100 GeV
VERITAS
MAGIC
CELESTE, STACEE, Solar Two
GLAST
10 GeV 1 GeV
AGILE
EGRET
100 MeV 10 MeV
HESSI
COMPTEL
1 MeV 100 KeV
INTEGRAL BATSE OSSE
HETE 2
SIGMA
RXTE
10 KeV
Super AGILE
BeppoSAX
Constellation-X
ASCA
1 KeV Chandra XMM
ROSAT 1992 1994 1996 Aldo Morselli 01/01 http://www.roma2.infn.it/infn/agile/
1998
2000
Year
2002
Swift 2004
XEUS 2006
2008
Aldo Morselli 6/9/99 http://www.roma2.infn.it/infn/agile/
GLAST Science Topics • • • •
• • •
Active Galactic Nuclei Isotropic Diffuse Background Radiation Cosmic Ray Production: – Identify sites and mechanisms Endpoints of Stellar Evolution – Neutron Stars/Pulsars – Black Holes Unidentified Gamma-ray Sources Dark Matter Solar Physics
• DISCOVERY! •
Gamma Ray Bursts
Scientific Heritage: CGROEGRET (E > 100 MeV) 3C279
Cygnus Region
Vela Geming a
Cosmic Ray Interactio ns With ISM
PSR B170644
LM PKS 0208- C 512
Cra PKS b 0528+134
3rd EGRET Source Catalog • 271 sources • 172 sources are unidentified
Diffuse Extra-galactic Background Radiation Is it really isotropic (e.g., produced at an early epoch in intergalactic space) or an integrated flux from a large number of yet unresolved sources? GLAST has higher sensitivity to weak sources, with better angular resolution. GLAST will bring alive the gamma-ray sky!
The origin of the diffuse extragalactic gamma-ray flux is a mystery. Either sources are there for GLAST to resolve (and study!), OR there is a truly diffuse flux from the very early universe.
Active Galactic Nuclei (AGN) Active galaxies produce vast amounts of energy from a very compact central volume. Prevailing idea: powered by accretion onto super-massive black holes (106 - 1010 solar masses). Different phenomenology primarily due to the orientation with respect to us. HST Image of M87 (1994)
Models include energetic (multi-TeV), highly-collimated, relativistic particle jets. High energy γ-rays emitted within a few degrees of jet axis. Mechanisms are speculative; γ-rays offer a direct probe.
Dark matter Rotational curve Dar matter halo
The Thedark darkmatter matterhalo haloisis necessary necessaryin inorder orderto to explain explainthe therotational rotational curve! curve! From Jungman et al, Phys. Rep. 267(1996)195.
Dark matter X-rays from a hot gas in a galaxy cluster An AnX-ray X-rayimage image(purple) (purple)that that shows showshot hotgas gassuperimposed superimposed on onaavisible visiblelight lightimage. image.
The Thegas gasisisso sohot hotso sothat thatthe the visible visiblemass massininthe thegalaxy galaxy cluster clusterisisnot notsufficient sufficienttoto keep keepit. it. ⇒ ⇒Dark Darkmatter! matter!
Candidates for Galactic Dark Matter • Massive Compact Halo Objects (MACHOs) • Low (sub- solar) mass stars. Standard baryonic composition. • Use gravity microlensing to study. • Could possibly account for 25% to 50% of Galactic Dark Matter.
• Neutrinos • Small contribution if atmospheric neutrino results are correct, since mν< 1eV. • Large scale galactic structure hard to reconcile with neutrino dominated dark mat
• Weakly Interacting Massive Particles ( WIMPs) • Non- Standard Model particles, ie: supersymmetric neutralinos • Heavy (> 10GeV) neutrinos from extended gauge theories.
WIMP Dark Matter Annihilations? Extensions to the Standard Model of Particle Physics also provide good candidates for galactic halo dark matter. This would be a totally new form of matter.
X X
Simulated response to 50 GeV side-entering γ’s Number of counts
If true, there may well be observable halo annihilations into monoenergetic gamma rays. q
or γγ or Zγ q “lines”? Energy (GeV)
Just an example of what might be waiting for us to find!
(6S)
Total photon spectrum from the galactic center from χχ ann. • Two-year scanning mode Infinite energy resolution With finite energy resolution
γ lines 50 GeV 300 GeV
Bergstrom et al.
Diffuse gamma ray flux from cosmological χχ ann. EGRET extragalactic diffuse data
In this case broader line due to redshift.
mχ = 86 GeV mχ = 166 GeV Bergstrom et. al. astro-ph/00105048
Best EGRET GRB GRB 940217
GRB Missions CGRO Beppo SAX HETE - II
Swift AGILE GLAST EXIST 1995
2000
2005
2010
2015
EGRET(Spark Chamber) VS. GLAST(Silicon Strip Detector)
EGRET on Compton GRO (1991-2000)
GLAST Large Area Telescope (2006-2015)
Large Area Telescope (LAT) γ Design Overview Instrument 16 towers ⇒ modularity
height/width = 0.4 ⇒ large field-of-view
Tracker Si-strip detectors: total of ~106 ch.
Calorimeter hodoscopic CsI crystal array ⇒ cosmic-ray rejection ⇒ shower leakage correction shower max contained < 100 GeV
Anticoincidence Detector Shield segmented plastic scintillator ⇒ minimize self-veto
e+
Flight Hardware & Spares 16 Tracker Flight Modules + 2 spares 16 Calorimeter Modules + 2 spares 1 Flight Anticoincidence Detector Data Acquisition Electronics + Flight Software
e– 3000 kg, 650 W (allocation) 1.75 m × 1.75 m × 1.0 m 20 MeV – 300 GeV
Calorimeter structure and design
Side panel
AFEE PEM
Closeout plate
CAL structure and design Corner aluminum
Bottom plate : alveolar structure aluminum attached to the Grid.
Carbon Fiber cells in compact geometry
Insert to attach Closeout Plate, AFEE, Side Panel
Crystal Detector Element (Wrapped)
Mylar tape Composite cell 3M film strip
Dual PIN diode
Kapton cable
Elastomer cord
CsI(Tl) ingot at AMCRYS
Light yield as function of position Left PMT, right PMT and average.
Light yield measurements June 2001
Performance Plots
(after all background rejection cuts, being updated)
FOV w/ energy measurement due to favorable aspect ratio
Effects of longitudinal shower profiling
Derived performance parameter: high-latitude point source sensitivity (E>100 MeV), 2 year all-sky survey: 1.6x10-9 cm-2 s-1, a factor > 50 better than EGRET’s
LAT Capabilities • Low deadtime – 8000 cm2 - LAT – 1500 cm2 - EGRET • Large FOV for detecting rare events – >2 sr - LAT – 0.5 sr - EGRET
Expected LAT Performance • 100 - 200 GRBs detected per year • Localization of 1 - 10 arcmin • Afterglows – ~25 afterglows/year
> 30 MeV
– ~ 4 afterglows/year
> 100 MeV
– 75% of afterglows will persist for À 2000 sec
-2 -1 Integral flux (photons cm s )
10
Sensitivity of γ-ray detectors
-7
5 sigma, 50 hours, > 10 events 10
EGRET
-8
AGILE 10
-9
Crab Nebula
GLAST 10
-10
All sensitivities are at 5σ. Cerenkov telescopes sensitivities (Veritas, MAGIC, Whipple, Hess, Celeste, Stacee, Hegra) are for 50 hours of observations. Large field of view detectors sensitivities (AGILE, GLAST, Milagro,ARGO are for 1 year of observation.
CELESTE, STACEE MILAGRO
MAGIC 10
10
-11
ARGO Whipple
-12
VERITAS 10
10
Large field of View experiments Cerenkov detectors in operation Past experiments HEGRA Future experiments
-13
-14
10
-1
10
0
10
1
Aldo Morselli 01/01 http://www.roma2.infn.it/infn/agile/
10
2
10
3
MAGIC sensitivity based on the availability of high efficiency PMT’s
HESS 10
Photon Energy (GeV)
4
Sky coverage of “all sky “ and Cerenkov telescopes in 2002 CAT HEGRA Magic
Milagro Whipple
AGILE
Cerenkov telescope “all sky” monitors
Conclusions Ð
GLAST will be an important step in gamma ray astronomy ( ~10 000 sources compared to ~ 200 of EGRET)
Ð
A partnership between High Energy Physics and γ−ray Astrophysics
Ð
Beam test and software development well on the way
Ð
Wide range of possible answers/discoveries, including possible dark matter detection
Ð
Gold era for multiwavelenght studies Be prepared, 2006 is near !
