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Contents
Appendix E
AN 98-OSS-03
ASCA Technical Description
ASCA
Guest Observer Facility -
Office of Guest Investigator Programs
Laboratory of High Energy Astrophysics
NASA Goddard Space Flight Center
Greenbelt
MD 20771
Emailed queries to: ascanra@athena.gsfc.nasa.gov
AO-7 VERSION
Contents
Preface to the AO-7 Version
Introduction
Purpose and Scope
Quick Comparison of the GIS & SIS
Latest Information
Figure Captions
ASCA Performance Update
XRT Performance
GIS Performance
SIS Performance
CTI, RDD, & spectral resolution
Hot and flickering pixels
Background
Satellite Operations Since the PV Phase
Observing Constraints
Scheduling
Constraints
Viewing Constraints
Sampling Constraints
South Atlantic Anomaly
Earth occultation
Regions of low geomagnetic rigidity
Angle from the bright Earth limb
Typical sampling window
Operational Constraints
``Contact'' and ``remote'' orbits
Telemetry rates and on-board storage capacity
Maneuvering and attitude determination
Choice of GIS & SIS modes
Placement of target in the field of view
Restrictions on Observing Time
Interpretation of requested time
Minimum observing time
Multiple close pointings at large extended objects
Time-critical observations
Figure Captions
XRT
Summary of Properties
Instrument Structure
XRT Capabilities
Effective area
Field of view
Plate scale
Spatial resolution
References
Figure Captions
GIS
General Principles
The Detector
Detector assembly
Gas cell
Phototube
The Data System
On-board data processing
Position determination
Background rejection
Observation Modes
Inflight GIS Performance
Energy resolution
Background
Useable field of view
Acknowledgements
Figure Captions
SIS
Introduction
CCD structure
Properties of the SIS CCDs
SIS Camera
Detection and Classification of Events
Observation Modes
CCD clocking modes
CCD data modes
Address and level discrimination
Mode choice
Inflight SIS Performance
Energy resolution
Background
Limiting sensitivity
Optical and UV light leakage
Echo
Hot and flickering pixels
Radiation Damage Monitoring and Predictions for the AO-7 Phase
CTI
Residual Dark Distribution
Predicted performance of SIS during AO-7
4-CCD mode
2-CCD mode
Status of 1-CCD mode
Predicted degradation in detection efficiency
Warm CCDs
Status of Fast mode
Acknowledgement
Figure Captions
Feasibility: GIS+XRT
Count Rate Limitations
Telemetry Limit
Limitations of Imaging Observations
PSF
Useable field of view
Limitations of Timing Observations
Choice of GIS bit assignment
Limitations of Spectral Observations
Pass band
Energy resolution
Effect of deadtime
Detection Sensitivity (GIS & SIS)
Figure Captions
Feasibility: SIS+XRT
Preamble: SIS Observing Modes and Feasibility
Count Rate Limitations
Telemetry Limit
Photon pile-up limit
Extended source observations
Limitations of Imaging Observations
PSF
Image scale
Limitations of Timing Observations
Imaging modes
Fast mode
Limitations of Spectral Observations
Effective Area
Resolution
Figure Captions
Simulations
Introduction
Helpful hints for good feasibilities
Common mistakes
Do I really have do a full-blown simulation?
Estimating source count rate using PIMMS
PIMMS terminology
Example I: estimating ASCA count rates
Example II: estimating ASCA count rates
Using XSPEC for Spectral Simulations
Getting started
Reading in the dummy data
Defining a model
Faking data
Fitting the fake data
PIMMS, VIEWING and ROLL
Introduction
PIMMS
viewing
roll
ASCA Personnel
How to Obtain and Install XSPEC
Where to find XSPEC
How to install XSPEC
Where to get help on XSPEC
Acronyms
About this document ...
Michael Arida
1998-06-02
