The following list provides a brief summary of each of the MPE
technical memos available at Goddard.
These memos are mainly informal,
sometimes in note form and many are pre-launch documents
which will have been rendered obsolete by in-orbit work.
Thus, these notes have not been circulated as preprints by MPE.
Due to user demand, however, we will provide these on request.
This list is intended to provide users with an idea of what information
is available, the date relates to the MPE internal release date
and gives some guidance as to which are pre-launch calibrations.
- Calibration Corrections to Individual PSPC Events,
MPE Memo TN-ROS-ME-ZA00/027
This document gives a summary of all calibration corrections
to be performed on individual PSPC events, starting out with
the raw detector co-ordinates and the event amplitude.
The correction algorithms detailed are:
- the ADC nonlinearity correction
- gain saturation correction
- temporal gain correction
- electronic position correction
- spatial gain correction
- window correction
- off-axis correction
- PSPC Position Dependant Gain Correction,
MPE Memo TN-ROS-ME-ZA00/025
This documents the position dependant gain corrections
applied to the data during SASS processing.
The position-dependant gain variations in the PSPC,
which amount to 3-5%, can be corrected by a position and
energy dependant function, yielding residual systematic gain
errors of order 1% over the whole sensitive area of the counter.
- The Effective Collecting Area of the ROSAT
Mirror Assembly and Predictions for the In-Orbit Data,
MPE Memo 1990 July
A brief note describing the ROSAT PSPC effective collecting
area as a function of energy and off-axis angle.
These plots are based on in-orbit data, and here the effective
area is defined as including all sources of obstruction within
the XRT mirror assembly except the PSPC window support.
- The PSPC Dead Time,
MPE Memo TN-ROS-ME-ZA00/026
It is found that the PSPC dead time per event is energy dependant
and changes with incident count rate. There are also differences
between the two PSPCs. It is concluded that for most of the time
the PSPC dead time will be dominated by vetoed particle background
events. This pre-launch document describes how the necessary
calibrations can be performed in-orbit.
- The Vignetting Function of the ROSAT Mirror
Assembly and Comparison with the PANTER Calibration Data,
MPE Memo TN-ROS-ME-ST01/062
The vignetting function is discussed.
In particular, the effects of the various hardware components between
the mirror assembly rear exit plane and the focal plane are discussed.
These are: the magnetic deflector; the apertures of the focal plane
housing ( which are holes in the sandwich plate and the carousel)
and the efficiency of the focal plane detector both on-and off-axis.
- Weitere Tests bezüglich des
Hotspot-Problems, MPE Memo TN-ROS-ME-ZA00/24
- Particle Background Analysis,
MPE Memo 1991 February
A discussion of the particle background, now superseded by
Snowden et al. (1992) and Plucinsky et al. (1993),
Astrophysical Journal papers (see items #8 and #9).
- The Particle Background of the ROSAT PSPC,
[Snowden et al.1992]
A detailed description of the ROSAT PSPC particle induced
The PSPC rejection efficiency for these spurious events is
exceptionally high with a residual count rate of roughly
counts s arcmin keV .
About 77% of events enter through the detector while the
remainder enter through the counter window.
During typical conditions the count rate of the residual
counts is well correlated with the Master Veto rate.
The spectrum of residual events consists of a flat component,
a soft power-law, and an Al K line at 1.5 keV.
Typically the ratio between the power-law and flat components
remains constant to % while the relative Al K
contribution increases with increasing MV count rate.
The distribution of counts over the field is uniform except for
a slight radial dependance and shadowing caused by blockage of
the externally producedcomponent by the window support structure.
- An Updated Calibration of the ROSAT PSPC
Particle Background, APJ Article
An update of the 1992 Snowden et al. paper.
Includes the post gain change calibration.
- The Focal Plane Instrumentation of the ROSAT
Telescope, SPIE Article
The reference to the published paper is 1987:
Proc. SPIE Int. Soc. Opt. Eng., 733, 519.
The published paper should be sought directly rather than
via the GOF.
- X-Ray Calibration of the ROSAT
Position-Sensitive Proportional Counter,
[Briel et al.1988]
The ground calibration measuring the differential spatial
non-linearities caused by the digitizing effects of the anode
and cathode grids are discussed.
In addition, the bulging of the thin PSPC entrance window
and the position dependant gain of the counter are detailed.
From those measurements MPE derive tables used to correct
individual events in position and pulse height.
Presented are the calibration methods and performance
achieved for the PSPC.
- Spectral Linearity Calibration of the ROSAT PSPC,
MPE Memo TN-ROS-ME-ED52/31
In this memo the Polya model function (for the spectral response)
is discussed, and compared to the empirical model of
- X-Ray Calibration of the ROSAT Position-Sensitive
Proportional Counter II, The Energy Calibration,
Describes the pre-launch measurements of the anode pulse heights
of the PSPC as a function of X-ray energy.
- Focal Plane Determination,
MPE Memo TN-ROS-ME-ST00/073
Reports an update of the focal plane determination procedure
compared to a 1989 July write-up.
- The Physical Composition of the PSPC Flight
Entrance Windows and the Flight Boron Filters,
MPE Memo TN-ROS-ME-ZA10/038
The transmissions of the entrance windows in the four PSPCs
are discussed, plus the boron filters.
A physical model is constructed for all known window components.
- Determination of Boresight Offsets for ROSAT
Detectors, MPE Memo TN-ROS-ME-ZA00/028
The boresight corrections, i.e., the systematic zero point shifts
encountered between the measured and known object positions
when expressed in detector co-ordinates, are discussed.
- ROSAT AMCS Status Report -
MPE Memo TN-ROS-ME-ZA00/030
- ROSAT Time Correlation (S/C-clock vs. UTC),
Time correction of the spacecraft clock.
- Komponenten: Der PSPC, Hasinger: 1992 February
On-axis point spread function, this is now written up in full,
- The On-Axis Point Spread Function: In-Flight
Comparison with the PANTER results,
MPE/OGIP Memo CAL/ROS/92-001
The components of the ROSAT PSPC on-axis point spread
function PSF are discussed, and a direct comparison made
between the predicted PSF from ground calibration measurements
and in-flight data obtained during the early part of the mission.
- Coordinate systems for the ROSAT Data Analysis,
MPE Memo TN-ROS-ME-ED34/002
The relationship between ROSAT coordinate systems
and celestial coordinates are discussed.
- The ROSAT PSPC Calibration Guide
A precursor to this document.
- Generation of Energy Dependant Exposure Maps
for ROSAT PSPC Analysis, Penn State Preprint
The importance of energy dependant exposure maps
for the analysis of ROSAT PSPC data is demonstrated.
Although current SASS generated exposure maps,
based on a single, band-limited instrument map,
are reasonably valid for central energies of the ROSAT bandpass,
analysis of softer bands(<0.20 keV) are strongly affected
by ``ghost'' images.
Correction for such effects is critical for studies of
extended objects and the diffuse X-ray background,
and may also affect the identification of soft point sources.
The authors present a method of generating energy dependant
exposure maps (7 bands) for any PSPC pointed observation.
These maps are based on instrument maps generated from
all-sky survey data (similar to the currently used instrument map
except for dividing the total PSPC bandpass into additional
Application of these maps will allow for accurate analysis
over the entire PSPC bandpass.
- Analysis Procedures for ROSAT XRT/PSPC Observations
of Extended Objects and the Diffuse Background,
[Snowden et al.1994]
A Here there be dragons paper for those
interested in reducing PSPC observations in order
to study extended objects of the SXRB.
- The Scattered Solar X-ray Background of the
ROSAT PSPC, APJ Article
This APJ paper models the scattered solar X-ray background
as seen by the ROSAT PSPC.
The temporal and geometric variation of this background component
is modeled and well reproduces the observed light curves.
The spectral distribution is also modeled with good results.
- Calibration Program for the PSPC Spectral
Response, 1993 February 22. No author listed.
Outline of planned calibration of the engineering model at
the PANTER facility in late 1993.
- The On-Axis Point Spread Function: Addendum -
High Signal-to-Noise In-Flight Data
MPE/OGIP Calibration Memo CAL/ROS/92-001a
The authors compare the ROSAT PSPC on-axis point spread
function PSF with the best signal-to-noise data
obtained to date for a point source.
They confirm that the parameterization detailed in
CAL/ROS/92-001 does satisfactorily describe the observed
PSF at energies keV.
- The Off-Axis Point Spread Function,
MPE/OGIP Calibration Memo CAL/ROS/93-015
This memo details the extension of the description of
the point spread function of the ROSAT PSPC to include
The authors present the off-axis PSF algorithm
and compare the model to in-flight data.
The limitations of the parameterization are discussed
with respect to data analysis.
- ROSAT PSPC: Informal Study Note -
Stability of the PSPC Spectral Calibration,
OGIP Calibration Memo CAL/ROS/93-007
The ROSAT PSPC data processing software SASS
gain corrects the pulse height analyser spectral data (PHA)
to pulse invariant (PI) data.
This study note tests the accuracy of those corrections
by making a simple ratio comparison between spectra of
a constant X-ray source, N132D taken at different epochs.
The analysis shows evidence for variations in the N132D spectra
which are interpreted as uncalibrated variations in the detector
- Mission Planning with ROSAT
The mission planning activities for the ROSAT project
- Study of the ROSAT XRT Startracker Problem,
MPE Memo TN-ROS-MPE-ZA00/029
The possible connection between difficulties in boresight
determination and the star tracker pixel calibration is discussed.
- The Effects of ROSAT Orbit Inclination
on the All-Sky Survey, MPE Memo TN-ROS-ME-ED52/29
A pre-launch document discussing the possible orbital inclinations
available One of a series of studies aimed at reducing the planned
orbital inclination from , eventually was
- Orbit Inclination and ROSAT Operations - Summary,
MPE Memo TN-ROS-ME-ED52/36
A pre-launch document summarizing a series of studies aimed at
reducing the planned orbital inclination from ,
eventually was chosen.
- In-Orbit PSPC Entrance Window Ablation
by Atomic Oxygen Bombardment, MPE Memo TN-ROS-ME-ED52/24
The expected oxygen particle flux in the XRT focal plane
was investigated in order to study the possible degradation
of the PSPC detector entrance window due to erosion
by neutral oxygen atoms.
- Data Aquisition and -Evaluation Electronics for
the ROSAT PSPCs, NIM Article
Discusses the on-board particle-background vetoing schemes
for the PSPC.
- Region Selection Bases on Detector Coordinates:
A Cautionary Note on Extracted Spectra,
MPE/OGIP Calibration Memo CAL/ROS/94-005
This memo is intended to remind Guest Investigators of the
importance of the effect related to ghost imaging in
spectra extracted under certain criteria.
- Assesment of Efforts to Improve the ROSAT
Attitude Solution, MPE Memo TN-ROS-ME-ZA00/031
Now App. D.
- The Stability of the Alignment between
the WFC and the XRT Star Trackers of ROSAT,
MPE Memo 1994 December 7
A comparison of the two different sets of attitude solutions
derived from the WFC and XRT star trackers is made for a
suitable selection of time intervals of steady state pointing.
To make it possible to substitute WFC for XRT attitude in
cases where the XRT solution is either non-existent or of
poor quality, the stability of the relative alignment of the
two star trackers (as inferred from the comparison of the two
data sets) is examined.
- ROSAT PSPC Calibration: Gain Variations,
MPE Memo TN-ROS-MPE-ZA00/032
A review of the systematic shifts in the PSPC spectral response.
- Status of the PSPC Spatial/Temporal Gain
Calibration - Analysis of the in-flight Al K data,
MPE/OGIP Calibration Memo CAL/ROS/95-003
The SASS PSPC data processing software corrects for time
and spatial variations in the detector gain as part of the
conversion from detected pulse height to pulse invariant channels.
Analysis of the in-flight Al K calibration data has shown
that there is an error in the spatial gain correction currently
applied in SASS, and also that there are uncalibrated effects
which need to be considered, requiring some additional correction
based on the detector coordinates and arrival time of each event.
- Calibration Correction Applied to Individual
PSPC Events, OGIP Calibration Memo CAL/ROS/95-010
[Turner et al.1995]
This document gives a summary of all the calibration corrections
applied to individual PSPC events during their conversion from
their arrival position and pulse height channel (PHA) to their
corrected coordinate and pulse-invariant (PI) channel.
This memo is essentially a copy of the original MPE memo
TN-ROS-ME-ZA00/027 (see item #1 -
but updated and expanded to refer to the FITS versions
of the calibration files available from the HEASARC.
- The ROSAT High Resolution Imager (HRI),
USRSDC SAO Calibration Report, revised 1996, February
[David et al.1996]
of this handbook.