GLAST LAT Project
Face to Face IDT meeting
March 20, 2002
Convener: E. do Couto e Silva
Tracker
“mini-tower”
Full Size
Calorimeter
module
Engineering Model/Prototypes schedule
including its use for GSE testing
Outline
Objectives
Hardware
Software
Important Dates
1
GLAST LAT Project
Objectives I
•
•
•
•
General
– Dress rehearsal of CU and LAT activities
– Understand and exercise interfaces across subsystems to
facilitate I&T coordination during CU and LAT activities
– Surface issues that may affect our schedule during CU and LAT
activities
Team building
– Must have involvement of non–US collaborators to develop
enough strength for CU and LAT activities
Test and procedures
– Handling (minimal)
– Transportation (minimal)
– Functional testing (rely on subsytems, I&T will provide support)
Mechanical and Electrical
– Subsystem level tests (not necessarily I&T issues)
2
GLAST LAT Project
Objectives II
• Data analysis
– Reconstruct low energy photons from Van der Graaf
– Measure energy spectrum and resolution (?)
• Calibration
– Test TKR low level calibration procedures
– Test CAL high and low level calibration procedures
– Test DAQ calibration procedures
– Verify ACD response to low energy photons ?
• EGSE
– Test Hardware/software/scripts/GUI
– First pass at FITS format (raw data only)
– Test SCL database
3
GLAST LAT Project
Objectives III
• SAS Software (EM will test some of the SAS tools)
– New geometry scheme (via XML)
– GEANT4
– TKR and CAL calibration algorithms
– SAS calibration database
– Data Manager and infrastructure for MC generation
• IOC
– I&T EGSE and SVAC products will be used to prototype
operations tools
4
GLAST LAT Project
Engineering Model (EM) hardware
•
•
•
•
•
ACD
– No hardware has been planned so far.
• Shall we try to get some tiles ?
TKR
– 4 trays fully instrumented (silicon and electronics) and tested (3
with no converter , 1 with thick converter).
• Maybe an additional bottom tray not instrumented ?
CAL
– Fully instrumented ?
EGSE
– Single TEM with “pseudo GLT” (no Event builder)
• If ACD then needs an Event Builder. How complicate does that
become ?
Cosmic Ray Telescope
– Do we need a telescope for external triggering or is self-triggering
sufficient ?
5
GLAST LAT Project
Engineering Model (EM) software
•
•
SAS
– MC Simulation
• What is the strategy for comparing GEANT4 and GISMO ?
• Which MC distributions do we validate ?
• First test of the new geometry scheme
– RECON
• Any new algorithms ?
• Does the small number of planes become a burden ?
– SAS Calibration Database.
• First test of the database concept
EGSE/Online
– EGSE
• Test Interface (API)
– Data Formats
• Raw Data in FITS format, RECON in ROOT
– Scripts (data taking, functionality, monitoring and calibration)
• Will most scripts be produced by subsytems ?
6
GLAST LAT Project
Engineering Model (EM) software
• I&T/SVAC
– Data analysis
• Are the current C++ analysis classes and ntuple
adequate ?
• Do we need any script/macro/ beyond what SAS
normally deliver ?
– Database.
• First test of prototype database
(http://www-glast.slac.stanford.edu/LAT/INT/SVAC/Database/svac_prototype_database.htm)
• First test of SVAC/SAS interface
• IOC
– Prototype of Operation Tools concept.
• Who will define and develop the web page, procedures,
automated reports, electronic log book, etc…?
• Does that help IOC CDR ?
7
GLAST LAT Project
Proposed Dates for the EM effort
• EM data taking (~60 days) - Jan 27, 03 – Mar 25, 03
• Hardware
– TKR EM to SLAC – Dec 02 (stays at SLAC)
– CAL EM to SLAC – Jan 03 (returns to CAL subsystem)
– I&T ready by Dec 02 (depends on I&T schedule)
– SAS ready by Dec 02 (planning for summer 02)
– EGSE ready by Apr 02 (since subsytems need them)
• Software
– EGSE scripts – Sep 02 (depends on I&T schedule)
– SAS - MC simulation – Jun 02 (planning for summer 02)
– SAS - New RECON – Jun 02 (planning for summer 02)
– SAS - calibration database – Oct 02 (current planning)
– I&T - SVAC database – Nov 02 (depends on I&T schedule)
– IOC - ops tools – Nov 02 (depends on I&T schedule)
8
GLAST LAT Project
“Calibration”
Science Requirement Document
443-SRD-00010
On-board calibration
On-board monitoring
On orbit calibration
S. Ritz note – see next slides
Systems Engineering ,
can you please check
flow down of
requirements from
L2 to L4 ?
Ground calibration
Ground monitoring
Ground calibration
I&T SVAC Plan
Ground monitoring
LAT-MD-00446
9
GLAST LAT Project
Low Level Calibration
Monitoring
Calibration
On board
Ground
Ground
On board
Ground
Map of
Hot and dead strips
TKR
Map of
Hot and dead strips
TKR
Number of
Hot and dead strips
TKR
Charge injection
Data using SAS software
histograms
10
GLAST LAT Project
High Level Calibration
Monitoring
Calibration
On board ?
Ground
Alignment
Alignment
Residuals?
Data using SAS software
histograms
“simple” track
finding
On board
Ground
11
GLAST LAT Project
Needs Revision and feedback
• The baseline is that we collect calibration data during normal
event data taking.
• Do we need one or more special modes ?
– Tracker alignment may require ~ 10000 tracks per tower
– ACD efficiencies may be better calibrated when tracks are
matched to pulse heights
– CNO mode ~ 10 Hz (?) of GCR for CAL calibrations
– Electronic calibrations (charge injection) may need a
special node ?
• What can be done on board and what is calibrated on the
ground ?
• What is the frequency of calibrations ?
12
GLAST LAT Project
On orbit calibration 1 ( from S. Ritz)
Reviewed by I&T Committee Meeting June 1, 2001 Present: Tony, Martin, Scott Williams, Scott Sawyer, Eduardo, Hartmut, Bob
Hartman, Steve, Tune Also sent to: Dave Thompson, Dave Bertsch, Seth Digel, Peter Michelson
CALIBRATION
Internal LAT alignment
(GCR)
LAT and Observatory
GN&C system.
CAL energy scales
ACD energy scales
Verify L1T efficiencies.
REQUIREMENT
VERIFICATION
Can be done at any time
First done at turn-on, after initial functional
during LAT I&T when DAQ is
check-out, with dedicated runs: estimate we operational using sea-level
need ~106 events . If done on the ground (30 cosmic-ray induced muons.
Hz accumulation), this corresponds to 10
We estimate that the full LAT
hours of data taking. It may be possible to do can be aligned this way in
<7(TBR) arcsec. this on-orbit at higher rate
less than one day.
Done piecewise during beam
test PSF studies. Also
possible to use mock data
First done after turn-on, functional checkout, challenge to validate the
and internal alignment. The current plan is to software tools. The error
do a pointed observation near the galactic
budget for both this
anticenter, where several bright, well-known, calibration and the internal
separated point sources will be in the FOV
alignment must be
<7(TBR) arcsec. simultaneously. As with EGR
established.
E. Grove SAS
workshop Sep
Planned CAL tests at GSI
(2000)
Done continuously using galactic CNO flux.
heavy ion beams.
L3 document
WHEN/FREQUENCY/DURATION
Done during beam test
Done continuously using galactic cosmic ray electron/hadron tests and seaflux and PHA readout.
level cosmic ray muon tests.
Done during beam test
electron/hadron tests and sealevel cosmic ray muon tests.
Must establish the precision
Done continuously using redundant triggers, requirement, based on the
specifically the CAL-LO trigger as a check on effective area knowledge
the TKR trigger.
error budget.
13
GLAST LAT Project
On orbit calibration 2 ( from S. Ritz)
Reviewed by I&T Committee Meeting June 1, 2001 Present: Tony, Martin, Scott Williams, Scott Sawyer, Eduardo, Hartmut, Bob
Hartman, Steve, Tune Also sent to: Dave Thompson, Dave Bertsch, Seth Digel, Peter Michelson
CALIBRATION
Offsets with viewing angle
(e.g. "fish-eye" effect)
Verify PSF over FOV
REQUIREMENT
WHEN/FREQUENCY/DURATION
Done after LAT-Observatory alignment after
turn-on. Observe bright, known point source
(e.g., Vela) at 4 (TBR) viewing angles (q, f).
Total time: ~1 week. More detailed
understanding of any subtle effects will be
obtained during the first year all-sky s
Done after LAT-Observatory alignment after
turn-on. The same observations used to
calibrate the systematic offsets will be used
for this analysis.
Verify background rejection
using first-year data,
analyzing the extra-galactic
diffuse measurement in bins
of varying background rates.
Done during first-year all-sky survey.
Effective area uniformity map
of instrument (e.g., Willis
analysis of EGRET data).
Verify effective area over
energy range (e.g., check for
"Kniffen factors")
Done during first-year all-sky survey.
Done during first-year all-sky survey.
Measure known source flux (e.g., Crab) to
lowest LAT energies.
VERIFICATION
Done during photon beam
test PSF studies, but does
this drive requirements
unnecessarily on fixture and
beam position knowledge?
Done during beam test PSF
studies.
N/A, but software tools can be
validated during mock data
challenge.
N/A
Low energy gamma beam
tests.
14
GLAST LAT Project
Type
ID
Name
Task
ACD High Level Calibration C1 Detection Efficiency
On board Ground Frequency
Processing
Calibration
●
1/month
ACD Low Level Calibration
C2
Veto threshold
●
1/week
ACD Low Level Calibration
C3
High Threshold
●
1/week
ACD Low Level Calibration
C4
Pedestals
●
1/day
ACD Low Level Calibration
C5
Electronic Gain and Linearity
●
1/month
TKR High Level Calibration
C6
SSD Alignment
●
1/year
TKR High Level Calibration
C7
Ladder Alignment
●
1/month
TKR High Level Calibration
C8
Tray Alignment
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1/month
TKR High Level Calibration
C9
Tower Alignment
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1/month
●
1/year
TKR High Level Calibration C10 LAT & Observatory Alignment
TKR Low Level Calibration
C11 Noisy Channels
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1/day
TKR Low Level Calibration
C12 Dead Channels
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1/day
TKR Low Level Calibration
C13 Uniformity of Calibration Signal
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1/day
TKR Low Level Calibration
C14 Threshold Scans
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1/day
TKR Low Level Calibration
C15 Time-Over-Threshold Signal
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1/month
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1/month
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1/month
CAL High Level Calibration C18 Light Attenuation
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1/month
CAL High Level Calibration C19 Light Yield
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1/month
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1/month
1/month
1/month
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1/year
TKR Low Level Calibration
C16 Time-Over-Threshold
Distribution
CAL High Level Calibration C17 Light Asymmetry
CAL Low Level Calibration
C20 Scintillation Efficiency
CAL Low Level Calibration
CAL Low Level Calibration
CAL Low Level Calibration
C21 Pedestals
C22 Electronic Gain
C23 Integral non-linearity
CAL Low Level Calibration
C23 Differential non-linearity
DAQ Low Level Calibration C25 Deadtime
DAQ Low Level Calibration C26 Time Accuracy
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1/day
1/day
From LAT-MD-00446
I&T
SVAC Plan
on orbit
Needs revision from
subsystems and
systems
engineering
15
GLAST LAT Project
Task
Type
Science Verification
Science Verification
Science Verification
Science Verification
Science Verification
Science Verification
Science Verification
ACD High Level Calibration
ACD Low Level Calibration
ACD Low Level Calibration
ACD Low Level Calibration
ACD Low Level Calibration
TKR High Level Calibration
TKR High Level Calibration
TKR High Level Calibration
TKR High Level Calibration
TKR Low Level Calibration
TKR Low Level Calibration
TKR Low Level Calibration
TKR Low Level Calibration
TKR Low Level Calibration
TKR Low Level Calibration
CAL High Level Calibration
CAL High Level Calibration
CAL High Level Calibration
CAL Low Level Calibration
CAL Low Level Calibration
CAL Low Level Calibration
CAL Low Level Calibration
CAL Low Level Calibration
DAQ Low Level Calibration
DAQ Low Level Calibration
ID
Name
S1 Number of Reconstructed Photons (Effective
Area)
S2 Absolute Energy
S3 Energy Resolution
S4 Single Photon Angular Resolution (on-axis)
S5 Single Photon Angular Resolution (off-axis)
S6 Field of View
S7 Background Studies
C1 Detection Efficiency
C2 Veto threshold
C3 High Threshold
C4 Pedestals
C5 Electronic Gain and Linearity
C6 SSD Alignment
C7 Ladder Alignment
C8 Tray Alignment
C9 Tower Alignment
C11 Noisy Channels
C12 Dead Channels
C13 Uniformity of Calibration Signal
C14 Threshold Scans
C15 Time-Over-Threshold Signal
C16 Time-Over-Threshold Count Distribution
C17 Light Asymmetry
C18 Light Attenuation
C19 Light Yield
C20 Scintillation Efficiency
C21 Pedestals
C22 Electronic Gain
C23 Integral non-linearity
C23 Differential non-linearity
C25 Deadtime
C26 Time Accuracy
1 tower 4 towers
LAT - 16 towers
EM FU CU SLAC NRL Spacecraft
Environ
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From
LAT-MD-00446
I&T
SVAC Plan
Pre launch
Needs revision from
subsystems and
systems
engineering
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16
GLAST LAT Project
ACD On orbit calibration
I&T SVAC Plan
LAT-MD-00446
Item
Number of tiles+ribbons PMT Energy range
Output data
Words Type Bytes/type Kbits
Detection efficiency
89+8
Value, error
97 Float
4
5.6
Veto Threshold
89+8
Value, error
97 Float
4
5.6
High Threshold
89+8
Value, error
97 Float
4
5.6
Pedestals
89+8
2
2
Value, sigma
388 Float
4
22.3
Gain
89+8
2
2
Slope, offset, errors 388 Float
4
44.5
To revise
data volume
metadata
data taking time
required bandwidth
calibration strategy (on board, ground)
Needs revision from subsystems and systems engineering
17
GLAST LAT Project
CAL on orbit calibration
I&T SVAC Plan
Item
Light Asymmetry
Light Attenuation
Crystals
1536
1536
Light Yield
Pedestals
Gain
Integral linearity
Differential
linearity
1536
1536
1536
1536
1536
Item
Light Asymmetry
Light Attenuation
Light Yield
Pedestals
Gain
Integral linearity
Differential
linearity
Ends/crystal Diodes/crystal
2
2
2
2
2
2
2
Number of items Coefficients
3072
9216
6144
12288
12288
12288
12288
6
6
1
1
1
50
4000
Energy range/Diode
LAT-MD-00446
2
2
2
2
2
2
2
2
2
Number of items
3072
9216
(sum of logs included)
6144
12288
12288
12288
12288
Values
Output data
Words
2
2
3
2
4
2
1
Value, error
Value, error
Value, stat and sys error
Value, sigma
Slope, error offset, error
Pulse height, ADC output
Delta of ADC output
38864
110592
18342
24576
49152
1228800
491520000
Type
Bytes/ty Kbits
pe
Float
4
1152
Float
4
3456
Float
4
576
Float
4
768
Float
4
1536
Long int
4
38400
Long int
4
1.5E+07
18
GLAST LAT Project
TKR on orbit calibration
I&T SVAC Plan
LAT-MD-00446
•Tracker calibrations are dominated by alignment, which is performed once a month (TBR)
on the ground using telemetry data. We expect only tray alignment calibrations will done at
least once after launch.
•The baseline (TBR) alignment (layer) requires 10000 tracks (TBR) crossing most of the
layers of each tracker tower. The exact number is TBD and depends on the criteria used to
select the event sample with larger number of straight tracks (proton-like). For all sixteen
towers we will require 16 105 charged tracks and if we expect a maximum of three hits per
layer with 2 byte/hit we obtain 2.7 105 Kbits. Statistics are generous to allow sufficient
tracks to align at the ladder and SSD level (once a year - TBR).
•The planning for operations shall include four dedicated runs for alignment at the tower
level for positions at sun minimum and maximum and entering and leaving the SAA once
every 2 months (TBR).
•The time over threshold can use the same 10000 tracks/tower designed for the alignment
but extra information needs to be send to the ground. If we assume 2 TOT values/layer of 1
byte each we obtain 4.5 104 Kbits.
19