Transcript ppt

GLAST LAT Project
Gamma-ray Large
Area Space
Telescope
Integration and Test CDR Peer Review, March 28, 2003
GLAST Large Area Telescope:
I & T Peer Review
Particle Test
Elliott Bloom
SU-SLAC
Subsystem Manager
[email protected]
650-926-2469
Document: LAT-PR-01779-01
Section 8 - Page 1
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Outline
 Flow of Requirements to/From Subsystems
 LAT Particle Tests
 Cosmic Rays and Van de Graaff
 Calibration Unit Beam Test
Document: LAT-PR-01779-01
Section 8 - Page 2
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
LAT Functional Performance (SE and I&T)
LATInstrumentPerformance
Verification Plan
LAT-M D-00408
T. Leisgang
SubsystemTest
Plans
Tracker Tower Test
Plan
LAT-TD-00155
LAT
Performance &
Operation Test
Plans
Com ponent
Aliveness Tests
Subsystem
IntegrationTests
ACD Test Plan
LATLim ited
Perform ance
Tests
ACD-PLAN-000050
LAT
Com prehensive
Perform ance
Tests
E. Gawehn
E-GSE
LAT-M D-01533
M .Huffer
R. Claus
L. Wai
LATOperational
Perform ance Tests
TEM
EP
PDU
GASU
LAT Contamination Control
LAT-M D-00404
Plan
J. Cullinan
E. Gawehn
LAT Instrumentation Plan
LAT-M D-00890
M .Lovellette
W. Davis
Facilities
LAT-M D-01386
LAT Survey & Alignment
L. Wai
LAT-M D-01586
LAT Survey Plan
LAT-TD-00895
L. Wai
M .Nordby
M echanical Weight & CG
LAT-M D-01598
E. Gawehn
L. Wai
LAT Dynamics Test Plan
LAT-M D-01196
Y Ismael
M .Lovellette
•Structural and Mechanical Tests
(cosmic ray survey)
• Thermal Verification Tests (cosmic
ray survey)
• Instrument Monitoring (cosmic
ray, Van de Graaff)
• End-to-end test (cosmic rays at ~
35,000 ft in a jet airplane during
transport to NRL for environmental
tests) (TBR)
ElectricalPerformance Tests
LAT-M D-01055
L. Wai
ThermalTests
LAT-M D-01837
M .Lovellette
E. Gawehn
LAT Thermal Test Plan
LAT-M D-01600
M .Lovellette
J. Wang
LAT EM I Tests
LAT-M D-01838
LAT EM I/EM C Test Plan
No Number
M .Lovellette
T. Leisgang
ElectronicsTest
Plan
LAT-TD-00296
SUI
LAT Handling
&Transportation Plan
LAT-M D-00452
D-00649
M -GSE
LAT-M D-01462
Dynamics Tests
LAT-M D-01836
E. Gawehn
M .Lovellette
M echanicalS/S
Test Plan
LAT-SS-00493
LAT Flight Software
Test Plan
LAT-TD-00786
LATM echanicalIntegration
LAT-PS-00676
E. Gawehn
L. Wai
Calorimeter Test
Plan
LAT-SS-00262
Thermal S/S Test
Plan
No Number
LAT Integration & Test Plan
LAT-M D-01376
E. Bloom
M .Lovellette
LAT SVAC Test Plan
LAT-M D-01587
E. do Couto E Silva
Particle Test Plan
LAT-M D-00440
G.Godfrey
Document: LAT-PR-01779-01
SVAC Plan
LAT-M D-00446
E. Do Couto E Silva
S. Ritz
Produce a
Working
Instrument
Section 8 - Page 3
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Science Performance (SE, IS, and I&T )
LATPerformance Specification
(LevelIIb)
LAT-MD-00010
ACD Subsystem Spec.
Tracker SubsystemSpec
(levelIII)
CAL Subsystem Spec.
(levelIII)
LAT-MD-00016
LAT-MD-00017
LAT-MD-0018
(levelIII)
•
•
SVAC Plan
LAT-MD-00446
•
(levelIII)
E. do Couto e Silva
S. Ritz
Particle tests (beam test,
cosmic rays, Van de Graaff)
Calibration (beam test, cosmic
rays)
Science verification tests
(beam test, cosmic rays, Van
de Graaff)
LAT SVAC Test Plan
Particle Test Plan
LAT-MD-00440
(levelIV)
G.Godfrey
LAT-MD-01587
(levelIV)
E. do Couto e Silva
Engineering Model
Calibration Unit
LATIntegration
LAT-MD-00573
(levelIV)
LAT-MD-00574
(levelIV)
LAT-MD-0575
(levelIV)
E. do Couto e Silva
E. do Couto e Silva
E. do Couto e Silva
Document: LAT-PR-01779-01
LATEnvironmental
Tests
LAT-MD-00576
(levelIV)
E. do Couto e Silva
LAT Mission
Integration
LAT-MD-00577
(levelIV)
LAT Phase 0 OnOrbit
LAT-MD-0581
(levelIV)
E. do Couto e Silva
E. do Couto e Silva
Produce a
Scientifically
Working
Instrument
Section 8 - Page 4
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Summary of Science Instrument Performance Verification (subset of Table 1 of LAT-SS-00010).
Req’t #
Req’t Title
1.Parameter
Verification
Method
5.2.1
Energy Range/
Effective Area
At Normal Incidence:
> 300 cm2 @ 20 MeV
>3000 cm2 @ 100 MeV
>6400 cm2 @ 300 GeV
T=Test
A=Analysis
T and A
1) Van de Graaff 17.6 MeV g
2) Tagged photons 100 to 1500 MeV, norm incidence
3) Brems beam, simultaneously all g energy bins from 20 MeV to 28 GeV, variety of
angles and transverse positions.
5.2.2
Energy
Resolution
On axis:
 50 % 20–100 MeV
 10 % .1-10 GeV
 20% 10-300 GeV
 6% >10 GeV, Incidence>60°
T and A
1) Van de Graaff 17.6 MeV g
2) Tagged photons 100 to 1500 MeV, norm incidence
3) Positrons 1,2,5,10,28, 45 GeV, variety of angles and transverse positions
5.2.3
Peak Effective
Area
>8000 cm2
T and A
1) Brems beam, simultaneously all g energy bins from 20 MeV to 28 GeV, variety of
angles and transverse positions.
5.2.4
Effective Area
Knowledge A/A, 1
<50% 20-50 MeV
<25% .05-300 GeV
T and A
1) Brems beam, simultaneously all g energy bins from 20 MeV to 28 Gev, variety of angles and
transverse positions.
5.2.5
Single Photon Ang
Resolution 68% (onaxis)
< 3.5° front @ 100 MeV
< 6° back
< 0.15° front @ 10-300 GeV
< 0.3° back
T and A
1) Brems beam, simultaneously all g energy bins from 20 MeV to 28 GeV, variety of angles and
transverse positions.
2) Tagged photons 100 to 1500 MeV, norm incidence
5.2.6
Single Photon Ang
Resolution 95% (onaxis)
< 3 x 68% On-Axis
T and A
1) Brems beam, simultaneously all g energy bins from 20 MeV to 28 GeV, variety of angles and
transverse positions.
2) Tagged photons 100 to 1500 MeV, norm incidence
5.2.7
Single Photon Ang
Resolution (off axis at
55°)
< 1.7 times on-axis
T and A
1) Brems beam, simultaneously all g energy bins from 20 MeV to 28 GeV, variety of angles and
transverse positions.
5.2.8
Field of View
> 2 sr
T and A
1) Brems beam, simultaneously all g energy bins from 20 MeV to 28 GeV, variety of angles and
transverse positions.
5.2.11
Time Accuracy
Better than 10 usec relative to S/C time
T and A
1) All Beam Test events record time from Linac RF
5.2.12
Background Rejection
>105:1 (TBR)
T and A
1) 200 K protons (Pattern rejection)
2) Cosmic rays on the ground (ACD rejection)
5.2.13
Dead Time
<100 usec per event
T and A
1) Ground cosmics
2) All Beam Test runs
Document: LAT-PR-01779-01
Beam Tests relevant to the Verification
Section 8 - Page 5
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Beams
• Cosmics rays on the ground
– EM, CU, LAT
• Van de Graff (17.6 Mev g)
– EM, CU (TBR), LAT (TBR)
• End Station A positrons (1-45 Gev)
– CU
• End Station A tagged photons (~100-1000 Mev)
– CU
• End Station A brems photons (> 20 Mev – 28 Gev)
– CU
• End Station A protons (~12 Gev)
– CU
• Cosmic rays in airplane (25,000 - 35,000 feet) (few hours) (TBR)
– LAT
Document: LAT-PR-01779-01
Section 8 - Page 6
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Ground Cosmic Rays (Examples)
•
Each tower as it becomes available at SLAC
– ~106 muons/day x 3 days (TBR) (use 3 in-a-row tracker trigger)
– Natural cosmic solid angle distribution. External muon telescope.
• Four Tower Calibration Unit
– Inter tower survey.
• Full LAT
– ~108 muons/day (using 3 in-a-row tracker trigger)
– Inter tower survey
– Calibrate individual CsI xtals
• ADC chans/MeV
• Positional dependence
– Calibrate tracker
• Dead and noisy strip map
• Straight tracks survey relative tray and tower positions
– Calibrate ACD
• ADC chans / MeV
• Calibrate discriminator thresholds
• Efficiency vs position
– Trigger and DAQ
• Efficiency vs position
For a full list of calibrations see LAT-MD-00446.
Document: LAT-PR-01779-01
Section 8 - Page 7
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
BGO Detector Array
Elements of
Scintillator
Telescope to
identify Cosmic
Rays.
BGO crystal array
used to calibrate
the energy of the
tagged photon
beam.
Phototubes
BGO crystals
Document: LAT-PR-01779-01
Section 8 - Page 8
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Van de Graaff Installed
Beam Pipe
Bldg 33 Clean Room
Inside Clean room
Heritage from previous use in Crystal Ball experiment by members of I&T.
This VDG was used for 8 years at SLAC and then shipped to DESY (Hamburg,
Germany). During this time it was used routinely for CB calibration using g lines
produced by the VDG.
Document: LAT-PR-01779-01
Section 8 - Page 9
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Van de Graff Produced g Spectrum
Gamma Spectrum from P+Li7
170.57 200
Counts / .27 MeV
counts
i
150
counts_u
counts_d
FitCB E
i
In Crystal Ball detector
i
100
i
FitEM E
i
50
0
0
0
0
5
10
15
E
i
Energy [MeV]
20
25
30
26.73
1)
The points are data (3335 events) from the Crystal Ball for the gammas from the reaction p+Li7.
2)
The black solid curve is the sum of a Breit-Wigner (Eresonance =12 MeV , FWHM G=5 MeV) and a
Gaussian (Eresonance=17.6 MeV, G ~ 10 keV, resolution = 1.3 MeV). The two curves have equal area
and add up to the total number of counts in the data.
3)
The red solid curve is what the EM would see with the GLAST LAT required resolution, assuming a
sum of two Gaussians ( = 50%, 50%, relative efficiency = 0.7, 1.0 ).
4)
The Li target produced 1060 Hz of gammas (E>7 MeV) into 4p solid angle (Measured in February
with the Van de Graff and BGO calorimeter in Bldg 33).
Document: LAT-PR-01779-01
Section 8 - Page 10
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Absolute normalization of VDG Flux
•
VDG Absolute Flux needs to be known if VDG used to establish < 100 MeV
Science requirements.
– Required to establish > 300 cm2 effective area for LAT @ 20 MeV
(TBR)
• BGO normalization of the g flux during EM, CU, LAT Measurements
– The g angular distribution from the target is expected to be isotropic.
Measurements at 0 and 45 degrees have initially confirmed this.
– Primary normalization method: The BGO calorimeter will be placed
at ~135 degrees to the beam direction (i.e., behind the target) while the
target is in front of the EM, CU, or LAT. Simultaneously counting the
photons into the solid angle of the BGO will yield the number of
photons going into the solid angle of the EM, CU, or LAT.
– Secondary normalization method (less accurate): The Van de Graff
operator will keep the energy and current of the accelerator constant
during the run, and then use the flux versus current calibration to
calculate the number of photons going into the solid angle of the EM,
CU, or LAT.
Document: LAT-PR-01779-01
Section 8 - Page 11
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Simulated Energy Spectrum from the VDG source
Linear Scale !!!
EB-W =12 MeV , FWHM G=6 MeV and a Gaussian
Eresonance=17.6 MeV, G ~ 10 keV)
90 000 MC signal events
(0.5 h of data taking
50 Hz rate from VDG)
Used as input to the MC
Energy (MeV)
Document: LAT-PR-01779-01
Section 8 - Page 12
GLAST LAT Project
TKR - Number of TRACKS
EM MC
Integration and Test CDR Peer Review, March 28, 2003
TKR – number of CLUSTERS
m
m
g
g
Cuts: TKR trigger
Differential distribution
Signal dominates
Negative values are
not shown
Document: LAT-PR-01779-01
Cuts: TKR trigger
Differential distribution
Signal dominates
Negative values are
not shown
Section 8 - Page 13
GLAST LAT Project
EM Energy Spectrum (TKR only)
Integration and Test CDR Peer Review, March 28, 2003
EM MC
Photons only
TKR energy (MeV)
Document: LAT-PR-01779-01
Section 8 - Page 14
GLAST LAT Project
EM MC
Integration and Test CDR Peer Review, March 28, 2003
Photons only
EM Energy Spectrum (CAL+TKR) in MeV
True MC Spectrum
Breit-Wigner (mean 11.4, FWHM = 6 MeV)
Delta function (17.6 MeV)
Event ratio 1:1
MC Reconstructed spectrum
90 000 MC signal events
(0.5 h of data taking)
Cuts: TKR trigger, TOT>0 below conversion layer, ECAL>0
Document: LAT-PR-01779-01
Section 8 - Page 15
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Beam Test Measurement Strategy
•
•
•
First, calibrate Four Tower Calibration Unit energy response
– 1– 45 Gev e+ with variety of x,y,θ (6 days) (small extrapolation to g with MC).
– Calibrate tagged photon beam with BGO array (energy calibrated with VDG).
– 100-1500 Mev tagged photons at normal incidence (2 days).
– 17.6 MeV g from Van de Graff (< 100 MeV) TBR.
Second, take photon data for testing the Monte Carlo (use CU for energy
measurement).
– Bremsstrahlung g beam at one e+ energy (28 Gev) ( 20 days)
– Simultaneously measures all g energies from 20 Mev to 28 GeV
– Bremsstrahlung spectrum has equal numbers of g per % width energy bin.
– The already energy calibrated LAT bins the photons into ±25% energy bins.
– An example of bin edges= [GeV]
– .017, .026, .038, .057, .086, .129, .19, .29, .44, .65, .98, 1.5, 2.2, 3.3, 5.0, 7.4, 11,
17, 25 GeV
Third, take hadron data for testing the simulation and measuring the pattern cut
rejection factor.
– ~200 K protons @ .0044 /pulse x 30 Hz x 30 days x .58 accelerator efficiency
– This is the number of protons we recorded in 30 days in Beamtest 99.
Document: LAT-PR-01779-01
Section 8 - Page 16
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
EXTRA SLIDES
Document: LAT-PR-01779-01
Section 8 - Page 17
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
Background Rate
Trigger rate = # of triggered events x 60000 cm2 x 1.67 /cm2/s /1,000,000 generated events
Vertical Position (3-in-a-row only) = 15.33 Hz
Vertical Position (W cut) = 13.94 Hz
Horizontal Position (W cut) = 2.54 Hz
W cut = 3-in-row reconstructed
events that Converted inside the W
foil (130.15 to 130.25 mm)
Energy (MeV)
Document: LAT-PR-01779-01
Section 8 - Page 18
GLAST LAT Project
Z
Integration and Test CDR Peer Review, March 28, 2003
Photons
Highest Photon flux
Highest Trigger efficiency
Lowest CR flux
Highest Trigger efficiency
X
UP
Y
TKR
Highest CR flux
Lowest Trigger efficiency
Document: LAT-PR-01779-01
For cosmic rays
YZ Plane:
Trade off between Flux and Trigger
efficiency
XZ Plane:
No Trade off between Flux and
Trigger efficiency rate is dominated by
trigger efficiency
Section 8 - Page 19
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
TOT right below the converter where conversion happens
m
We should be able to see this
difference in the VDG test if the
TOT is working .
MC
We need to “calibrate” the TOT with muons
g
X – axis = TOT*cosz
DAC counts
Cuts: TKR trigger, TOT>0 below conversion layer. Found track along Z direction, needed to normalize to normal incidence.
Document: LAT-PR-01779-01
Section 8 - Page 20
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
TOT “Calibration” with Muons Tower Vertical - MC
This is the TOT one expects for Muons in a
given TKR layer from Monte Carlo
Simulations
Muons: 1 Mip ~ 33 to 37 counts
DAC counts
Cuts : TKR trigger, 1 track and 1 vertex
Document: LAT-PR-01779-01
Section 8 - Page 21
TOT “Calibration” from muons - DATA
GLAST LAT Project
Integration and Test CDR Peer Review, March 28, 2003
(using EGSE and the GTRC chip v3 that is in the EM ! At SLAC)
Merci Johann !!
Muons: 1 Mip ~ 15-20 counts
This is the TOT already working with real
data !
DAC counts
Document: LAT-PR-01779-01
Section 8 - Page 22