2004) upload

We have succeeded in getting the correct images.

In this time, we moved the mask slightly apart from the nominal position by the values we obtained from the last simulation as follows:

maskoffx = -0.104 [cm]
maskoffy = +0.308 [cm]
maskoffz = +0.085 [cm]

We made three runs with generating photons at different positions at infinity:

Then the three positions are,

source on-axis, at infinity
source at 45 degrees from axis, phi = 0, at infinity  (i.e. along BAT_X)
source at 30 degrees from axis, phi = 90, at infinity (i.e. along BAT_Y).

From each output eventlist which is generated from the Sim-SwiMM, firstly we make the detector plane images by FTOOL "fv", secondly we convert the detector images to the sky image by using BAT FTOOL "batfftimage", and search each peak position in the sky images using BAT FTOOL "batcelldetect". As following, we show calculated results at the bottom of the pictures (e.g. IMXcent, IMYcent ...).

Conclusively, we could evaluete the source positions to an accuracy of less than 0.1 arcminutes from the result of three simulations.

Detector Plane Images and Sky Images

(1) source on-axis

IMXcent  IMYcent     IMXwid   IMYwid    Peak Cts Bkg Cts Bkg Var
-0.00001  0.00001    0.00278  0.00278    282823.3  -275.2  1837.7
= (-0.00057 deg, 0.00057 deg)
= (-0.034 min, 0.034 min)

(2) source at 45 degrees from axis, phi = 0

IMXcent  IMYcent     IMXwid   IMYwid    Peak Cts Bkg Cts Bkg Var
0.99996  0.00002    0.00282  0.00282    117551.5   -92.7  1114.3
= (44.99885 deg, 0.00115 deg)

(3) source at 30 degrees from axis, phi = 90

IMXcent  IMYcent     IMXwid   IMYwid    Peak Cts Bkg Cts Bkg Var
-0.00001 -0.57736    0.00286  0.00286    118906.6  -611.0  1524.2
= (-0.00057 deg, -30.00042 deg)

How to calculate a degree

We are able to change a sky image positon into a degree unit multiplied by arctan (IMXcent) and arctan (IMYcent). And we can get an arcminute unit multiplied by 60 min/deg.