Solar Images and Spectra from the Solar Maximum Mission (SMM) X-ray Polychromator

Data from the X-ray Polychromator (XRP) consist of photon counting
rates at selected X-ray wavelengths in the 1.4 - 22.5 A band from
detectors which are used in a variety of modes to build up solar
images with various spatial dimensions.

Approximately 100 GB of data have been returned by XRP during the
mission. XRP data are processed through several stages to yield image
and spectral data. A comprehensive collection of flare data, software
source code and user documentation, and catalog of observations is
available for use at the Solar Data Analysis Center (SDAC). Requests
for data and information should be first addressed to the SDAC (GSFC
Code 682). Other collections of selected data are held at Lockheed
Palo Alto Research Lab. and Mullard Space Science Lab.

The XRP consists of two instruments, the Bent Crystal Spectrometer
(BCS) and the Flat Crystal Spectrometer (FCS). Both instruments
measure the individual emission lines which dominate spectra from the
solar corona and flare X-ray plasmas, to diagnose their temperatures,
densities, velocities, abundances, and non-equilibrium states of all
phases of flares and active regions. The BCS was designed for high
time resolution studies in lines of Fe I - Fe XXVI and Ca XIX. It
covers its entire spectral range at once, and integrates spatially
over an entire active region with a field of view of 6 arc min FWHM.
The FCS provides mapping of flares and active regions in the resonance
lines of 7 ions between O VII and Fe XXV with 14 arc sec resolution
and a field of view up to 7 arc min. It can also spectrally scan the
1.4 - 22.5 A band.

Many of the various instrument modes have been utilised during its
operational life, so there is a great variety of kinds of data
arrays. They fall into several simple categories:

FCS images - These vary from 15 arc sec to 7 arc min in either
dimension with a step size from 5 arc sec to 20 arc sec. Each is made
in a chosen spectral line, and the integration time at each pixel is
chosen between 0.256 s and 1 hour.

FCS spectra - These data were made over various portions of the 1.5 -
22 A band.

FCS light curves - These data were obtained when the FCS identified a
bright point and locked onto it ('sit-and-stare' mode) to give
continuous fluxes for a preset period (0.256 s to 1 hr) with 0.25 s
time resolution.

Hybrid FCS modes - Most FCS observations consist of combinations of
the above three types of data, either pre-programed according to
science objectives of the observing day, or interrupted by changes of
mode in response to flare alarms.

BCS spectra and light curves - The BCS gathers spectra every 11 s,
with 1660 spectral bins at full spectral resolution.