
The IBEX Lo sensor calibration data are contained in four comma-separated
text spreadsheet files.  Three of these files (lo_cal_dat_H_interp.csv,
lo_cal_dat_He_interp.csv, and lo_cal_dat_O_interp.csv) include data describing
the sensitivity of the Lo sensor to incident H, He, and O atoms.  The fourth
file, Coll-FoV_PointSpread.csv, gives information descriptive of the Lo
point-spread function.

The lo_cat_dat_<species>_interp.csv files consist of 23 columns of data, where
<species> can be H, He, or O.

A.  k is the energy band of the incident ENA
B.  i is the energy band in which the ENA was detected
C.  E (center) is the center energy of band i
D.  dE/E is the spectral resolution of the sensor in band i
E.  absoluteGF is the absolute geometric factor in cm2 sr of the collimator 
    (obtained from the Collimator Calibration Report). This is the only place
    where an absolute geometric factor comes in.  This factor is independent 
    of species, energy, and time over the mission.
F.  non-Energy dependent losses is the combined transparency of all grids 
    between collimator and TOF subsystem, 
G.  <Species> conversion efficiency is the combined conversion and reflection 
    efficiency rolled in the geometric factor evaluation. It depends on 
    the incoming species s, the incoming energy E (energy band k), and 
    the energy step (i) in which the particles are detected. 
    This comprises the total number of particles 
    collected from the surface. The branching into different species through 
    conversion and sputtering processes is rolled into the yield matrix (K-M).
H.  TOF transparency is the transparency of all the TOF system grids
I.  TOFdbl is the TOF efficiency for detection of a double event
J.  TOFdbl is the TOF efficiency for detection of a triple event
K.  %H gives the probability of detection of the ENA of incident species 
    <species> as Hydrogen
L.  %C gives the probability of detection of the ENA of incident species 
    <species> as Carbon
M.  %O gives the probability of detection of the ENA of incident species 
    <species> as Oxygen
N.  H eff double is the effective TOF efficiency for the detection of 
    a double event if 100% of the detected particles were just 
    the majority species (H for incident H and He; O for incident O)
O.  H eff triple the effective TOF efficiency for the detection of 
    a triple event if 100% of the detected particles were just 
    the majority species (H for incident H and He; O for incident O)
P.  Species check is the sum of columns K-M and should be very close to 1
    It demonstrates the goodness of the branching analysis
Q.  E-step (obs) is the energy band of a detected ENA (equal to i)
R.  GF double is the geometric factor for detection of doubles from incident
    ENAs with energy given in column Q in units of cm2 sr keV/keV 
    (summed over all detected species)
S.  GF triple is the geometric factor for detection of triples from incident
    ENAs with energy given in column Q in units of cm2 sr keV/keV.
    (summed over all detected species)
T.  E-Step neutral energy is the energy band of an incident ENA (equal to k)
U.  Same E-step indicates when incident and observed energies are identical
V.  GF double is the geometric factor for detection of doubles from detected
    ENAs with energy given in column T in units of cm2 sr keV/keV.
    (taken only for detected majority species: H for incident H and He; 
     O for incident O) 
W.  GF triple is the geometric factor for detection of H triples from detected
    ENAs with energy given in column T in units of cm2 sr keV/keV.
    (taken only for detected majority species: H for incident H and He; 
     O for incident O)



Point-spread-function 
=====================

Coll-FoV_PointSpread.cvs gives the point spread function of the collimator.
The Point Spread Function is currently given analytically only for the two 
cardinal cuts across a symmetric hexagon: across the corners of the hexagon 
and across the base of the hexagon. The values given Coll-FoV_PointSpread.csv
are the transparency for a homogeneous parallel beam of particles as a 
function of angle Θ (column A) relative to the normal direction of the 
collimator grids for cuts along the base of the hexagon (columns B and D)
and between the corners of the hexagon (columns C and E).  Columns B and C
are for the Lo sensor in its normal mode of operation;  columns D and E
apply to the high-resolution mode which has not yet been used on IBEX.

The transparency is normalized to 1 for a beam incident at the normal
direction, i.e. for which the hexagons are exactly aligned. 

