% Time-stamp: <97/06/25 17:49:45 dph> 
% MIT Directory: ~dph/h1/ASC/TG/Flight/Development/Cal_prods
% CfA Directory: /dev/null
% File: Cal_inputs.tex
% Author: D. Huenemoerder
% Original version: 970624
%=====================================================================

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\Header{Analysis Calibration Inputs}{dph \today}

\begin{document}

\title{Calibration Input Data Required for Grating Processing}
\author{David Huenemoerder}
\maketitle
\makecsrhead{-55}{}

\section{Analysis Reference Data {\em vs.} Calibration Interface Products}

Standard data processing requires instrument calibration data at many
stages of analysis.  These products need to be provided in well
defined, stable products, with inclusion of self-descriptive ancillary
information.  These analysis inputs are not necessarily identical to
the outputs of the calibration effort.  Hence, Analysis calibration
inputs need to be defined and derived from calibration end-products.

D.~Dewey has termed the analysis inputs as {\em Analysis Reference
Data} (ARD) and the calibration end-products as {\em Calibration
Interface Products} (CIP).  (For a description of HETG calibration
data, see {\tt http://space.mit.edu/HETG/xrcf\_cal/cal\_prods.html}).
The distinction is similar to the {\em Basic Calibration Files} (BCF)
and {\em Calibration Product Files} (CPF) defined for other missions
by the NASA-Goddard High Energy Astophysics Science Archive (HEASARC;
quoted from 
{\tt ftp://legacy.gsfc.nasa.gov/caldb/data/README}):

\begin{quote}
  Basic Calibration Files contain basic calibration information such as 
        the effective area, energy resolution, point-spread function 
        of the instrument. In many ways these datasets can be thought of 
        as the ``atomic'' units of calibration.

  Calibration Product Files contain ``higher'' level calibration products
        (which can usually be generated using BCF datasets) suitable 
        for specific data analysis tasks. Examples include exposure maps,
        response matrices etc.
\end{quote}

This document tabulates the Analysis Reference Data currently defined
for AXAF grating processing through Level 1.5 and exposure map
calculation. (See for example, the Level 1.5 description in
{\tt http://space.mit.edu/ASC/analysis/L1.5\_overview/L15.html}.)  

After naming the two sets of data, the process connecting them must be
defined.  While this may never be totally automatic, there should be
easy tests for new CIP and tools to compute new ARD if CIP are newer. 

\section{Grating Analysis Reference Data (GARD)}

The following table collects reference data from specified grating
data processing, from the Level 1.5 flight processing and from
exposure map specifications.  Along with the descriptions are
suggested file formats.  Some of these ARD are very close to a CIP,
being mainly a difference in format; the grating efficiency is an
example.  Others will require some analysis; HRMA performance is
typically specified as parameters for a ray-trace, rather than as a
table or function.



%
\begin{table}[htbp]
\begin{center}
  \caption{Grating-related Analysis Reference Data}
  \label{tab:gard}
  \begin{tabular}{|cp{3.1in}p{0.9in}|}\hline
    \multicolumn{1}{|c}{Definition}&
    \multicolumn{1}{c}{Description}&
    \multicolumn{1}{c|}{Suggested Format}\\\hline
    &&\\[2mm]
%
    Hfw$(E,\theta; \%EE)$&
    HRMA PSF full-width versus energy and
    off-axis angle, for a specified fractional enclosed energy
    ($\%EE$).&
    function;\newline
    parameter file\\[4mm]

    $R_{\mathrm{TG}}(n)$&
    Grating ring radius for shell $n$.&
    parameter file\\[4mm]

    $X_{\mathrm{TG}}$&
    Grating Rowland spacing: the as-installed distance
    from the grating node to the on-axis focal point.&
    parameter file\\[4mm]

    $TG\_angles$&
    Mean clocking angles of the facets as installed,
    relative to the AXAF $y$-axis.&
    parameter file\\[4mm]

    $P_{\mathrm{TG}}$&
    Grating mean periods.&
    parameter file\\[4mm]

    Geometry&
    Various geometric parameters, such as
    detector geometry, HRMA node, HRMA to grating spacing --- all
    incorporated into {\tt pixlib} for coordinate transformations.&
    parameter file\\[4mm]
    
    Dhw$_{\pm}(E;\mathrm{cid}, \%EE)$&
    Detector pulse-height (PI) distribution half-width ($hw$) as a
    function of energy, $E$, for a specified chip (cid), and for a
    specified fractional enclosed energy ($\%EE$). (A two-sided
    ($\pm$) parameterization is required since it is an asymmetric
    distribution.)&
    function;\newline
    FITS bintable;\newline
    parameter file\\[4mm]

    $A_n$&
    Mirror geometric area for shell $n$.&
    parameter file\\[4mm]

    $H_0(E,n)$&
    Mirror on-axis efficiency as a function of energy
    and shell. &
    FITS bintable\\[4mm]

    $V(\theta,E,n)$&
    Mirror vignetting as a function of off-axis
    angle, energy, and shell.  This is defined by
    $V=H_0/H(\theta,E,n)$. &
    FITS bintable\\[4mm]

    $G_n(E,m)$&
    Grating efficiency for shell $n$ as a function of
    energy and order.  This is averaged over all facets on a given
    shell. &
    FITS bintable\\[4mm]

    $\overline{q}(E)$&
    Detector spatially averaged quantum efficiency
    as a function of energy.&
    FITS bintable\\[4mm]

    $U(E,x_d,y_d)$&
    Detector uniformity, as a function of energy an
    position. &
    FITS images\\[2mm]

    $Bad(x_d,y_d)$&
    Detector bad pixel locations &
    FITS table\\[2mm]\hline
  \end{tabular}
\bigskip

\Putline 
\medskip
\Note{NOTE: It is likely that simple parameters will come
  directly from the ASCDS archive into parameter files, and that the
  archive will hold the associated descriptive meta-data.}

\end{center}

\end{table}




\end{document}




