Didier Barret created 22/07/2018

Official and latest X-IFU response matrices can be downloaded from:
    - http://x-ifu.irap.omp.eu/resources-for-users-and-x-ifu-consortium-members/

References to use for the matrices: Barret et al. (2018, 2016, SPIE) and Ravera et al. (2014, SPIE)
    - http://adsabs.harvard.edu/abs/2018SPIE10699E..1GB (** this is the latest to quote first **)
    - http://adsabs.harvard.edu/abs/2016SPIE.9905E..2FB
    - http://adsabs.harvard.edu/abs/2014SPIE.9144E..2LR

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Log changes:
    - 22/07/18: Creation of the first set of matrices
    - 03/08/18: Added a new curve for the spectral resolution versus energy to match 2.5 eV at 7 keV
    - 03/08/18: Fixed a missing TLMAX4 keyword in FITS header (TLMIN4 was duplicated) - Thanks to S. Heinz 
    - 21/08/18: Fixed column name CHANNELS into CHANNEL in the EBOUNDS extension - Thanks to J. de Plaa
    - 10/10/18: Matrices updated to account for an increased pixel pitch (from 249 to 275 microns). IPRR baseline
    - 05/12/18: Added a Matrix with the Be filter and a 10 eV resolution (suitable for Crab instensity sources)
    - 05/12/18: Added IPRR-X-IFU-RESPONSE-FILES-V1.2.pdf: A TN describing the assumptions made to build the IPRR matrices
    - 05/12/18: Added throughput curves for high resolution events and 10 ev resolution events
    - 05/12/18: Added explanation about the *aeff files found in the directory - Thanks to C. Pinto
    - 17/02/21: Change keyword LO_THRES from 0.05 to 0.0 - Upon ACO request and SIXTE team
    - 18/05/21: Uploaded the file XIFU_CC_BASELINECONF_2018_10_10_EXTENDED_LSF_x33.rmf and the file XIFU_extended_LSF.pdf
    
Any further comments/issues: dbarret@irap.omp.eu
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# Latest update 

An RMF file with an extended Line Spread Function was generated by Valentina Fioretti for testing. See the attached 
documentation in the XIFU_extended_LSF.pdf file.


Responses matrices are provided for the so-called cost-constrained mission configuration.

************************************* mirror configuration used *****************************************************
filein='area_B4C_Ir_0.0_hires_TWGcorr.dat.txt'
https://www.cosmos.esa.int/web/athena/resources-by-esa
15 rows, 2.3 mm rib pitch, Ir+B4C coating (nominal configuration, requirement-compliant, 1 eV resolution)
Downloaded May 29th, 2018, data courtesy of Prof. Richard Willingale (University of Leicester)
Mirror Assembly (MA) with 15 rows, 6 sectors, 678 mirror modules
Active mirror aperture radius 259-1183 mm
Mirror plate rib spacing (pitch) of 2.3 mm
Ir+B4C coating on the mirror modules at all radii
Courtesy Tim Oosterbroek and validated by Matteo Guainazzi against Dick Willingale ray-tracing calculations
Caveat: The saw-tooth effect in the arf at high energy is a known effect of the reflectivity files downloaded from the CXRO web site
They are most likely due to numerical issues with the software producing the reflectivity tables for download.
**********************************************************************************************************************
    
X-IFU_CC_Baseline_DATE: This is the matrix to be used as this represents the baseline configuration of the instrument.
The energy dependency of the spectral resolution is assumed to be flat below 7 keV and goes up linearly to 4.8. This is the one to 
use by default.

XIFU_CC_BASELINECONF_IMPROVED_SPECTRAL_RESOLUTION_DATE is the same as above but a polynomial form is assumed for the 
spectral per the Barret et al. (2018, SPIE) paper. 
That is: de=2.166 + 0.03182*energyinkev+ (-0.0003199)*energyinkev**2 + 0.0001892*energyinkev**3 (no margin included).
An impprovement at low energies is predicted.

Alternatively,including the margins, the relation croissing 2.5 eV at 7 keV would be:
de= 2.23583428 + 0.03089*energyinkev+ (-0.00033107)*energyinkev**2 + 0.00018705*energyinkev**3
The response file is called: XIFU_CC_BASELINECONF_IMPROVED_SPECTRAL_RESOLUTION_WITH_MARGINS_DATE

Filter wheel positions considered:

XIFU_CC_BASELINECONF_BEFILTER100MICRONS_DATE: 100 microns Be filter

XIFU_CC_BASELINECONF_BEFILTER100MICRONS_10eV_DATE: 100 microns Be filter (and 10 eV resolution assumed throughout the energy range, for ~1 Crab source sim.)

XIFU_CC_BASELINECONF_THINFILTER_DATE: Thin optical filter (200 nm Polyimide and 40 nm Aluminum, mesh blocking factor of 4%)
XIFU_CC_BASELINECONF_THICKFILTER_DATE: Thick optical filter (200 nm Polyimide and 90 nm Aluminum, mesh blocking factor of 4%)

See attached TN. More advanced filter configurations are being considered with the aim of optimizing the transmission. 

The Crab reference spectrum used in the X-IFU performance requirement document is also given as an xcm file.

The *.aeff files are ascii files containing the effective area curve of the given response matrix.

Comments/Questions: email dbarret@irap.omp.eu