HETG Models

Efficiency Model S/W

• Rectangular Efficiency ( dd IDL code)
• Tilted or multi-vertex Efficiency ( dd IDL code)

• Multi multi-vertex Efficiency (by John E. Davis, written in S-Lang)

  Takes a file with one or more multi-vertex-grating-parameter-sets and calculates the average efficiency at a set of energies and range of orders.
  

  • Example available in ~dd/eff_demo/ at MIT and SAO:
  • energy.dat is an ASCII list of energies desired (here 0.2 to 0.3 keV in 0.1 steps.)
  • test_multi.txt is the list of gratings (here a single one) and their parameters; this format is specified in jfit_multi_format.txt. These multi.txt files may be stored in rdb format, see the column names in the flight multi.rdb files.
  • multi.sl is the S-Lang "program" which performs the calculation. The first six lines specify the operation (input/output files) and range of orders to be calculated.
  • optical-constants.tbl is the data set for the X-ray properties of the gold, chromium, and polyimide which makeup the Chandra gratings. These values are initially created using Mark Schattenburg's "xray" program, see Note from John Davis. This file is a text version of the MARX 2.04 distribution file optical-constants.dat (in John Davis binary format.)
  • The calculation is executed by typing to unix:
    • ~dd/bin/solaris/eff multi.sl
  • test_multi.out is the output from the model consisting of tab-delimited lines with energy and the efficiencies in the orders for the composite set of gratings (here, orders are -1,0,1 only.)

• Validating John's efficiency code...
  • The model parameters and efficiencies created by John's code were compared with the efficiencies created by the brute-force calculation carried out by labxray/tilt_effic.pro.
  • The model parameters and multi-vertex shape used for the test are shown here; the corresponding path-length function used by tilt_effic is shown here.
  • John's efficiencies are the solid lines and diamonds in these plots; the *s are the tilt_effic efficiencies.
  • FYI, The diamonds and *s are at the "pruned" energies: interpolating between these will retain a 1% accuracy.
  • This comparison was carried out with the procedure jfit/jfit_tilt_compare.pro.

LRF/Ray-trace Model S/W

• Error Budget for E/dE ( dd IDL code)
• MARX (HRMA/HETG/ACIS)
• SAOSAC-rays + MARX-HETG + TBD_ACIS
• MARX with quasi-faceted-HETG for mis-aligned MEGs
• SAOSAC with fully-faceted-HETG (e.g., ray-trace of HETG during insertion!)

Model Products

• See the HETG Calibration Interface Products page for the current HETG data products: http://space.mit.edu.ezproxyberklee.flo.org/HETG/xrcf_cal/cal_prods.html#HETG_CIP

This web page is: http://space.mit.edu.ezproxyberklee.flo.org/HETG/models/models.html.
Please send any comments and updates to: dd@space.mit.edu.