1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
/*****************************************************************************
* Johns Hopkins University
* Center For Astrophysical Sciences
* FUSE
*****************************************************************************
*
* Synopsis: cf_ids_dead_time(fitsfile *header, long nseconds,
* float *aic_rate, float *ids_dtc)
*
* Description: Computes the weighting factor needed to correct
* for the IDS dead time.
*
* Arguments: fitsfile *header Pointer to FITS file containing the
* header of the intermediate data file
* long nseconds The number of timeline values
* float *aic_rate An array of Active Image Counter
* values
* float *ids_dtc Dead-time correction array (returned)
*
* Calls:
*
* Return: 0 on success
*
* History: 10/27/02 1.1 peb Begin work
* 11/11/02 1.2 peb Correct function description and add
* cf_timestamp after IDS__COR check.
* 12/09/02 1.4 wvd Calculate DT correction for each time
* step, then apply to photons.
* Set keyword IDS_DEAD.
* 05/20/03 1.5 rdr Add proc_check call.
* 08/01/03 1.8 wvd Just calculate correction; don't
* apply it. Return ids_dtc array.
* 08/04/03 1.9 wvd Convert aic_rate to type short.
* 11/26/03 1.10 wvd Convert aic_rate to type float.
* 02/09/04 1.11 wvd max_ids_rate depends on instrument
* mode. For TTAG data, include time
* stamps in aic_rate.
* 04/07/07 1.12 wvd Clean up compiler warnings.
*
****************************************************************************/
#include <string.h>
#include "calfuse.h"
int
cf_ids_dead_time(fitsfile *header, long nseconds, float *aic_rate,
float *ids_dtc)
{
char CF_PRGM_ID[] = "cf_ids_dead_time";
char CF_VER_NUM[] = "1.12";
char elecfile[FLEN_VALUE], instmode[FLEN_VALUE];
int errflg=0, status=0;
long k;
float ids_rate, tstamps, ttperiod;
float mean_ids_dtc = 0.;
float max_ids_rate = 1.;
fitsfile *elecfits;
cf_error_init(CF_PRGM_ID, CF_VER_NUM, stderr);
cf_timestamp(CF_PRGM_ID, CF_VER_NUM, "Begin Processing");
if ((errflg = cf_proc_check(header, CF_PRGM_ID))) return errflg;
/*
* Read observing mode and interval between time stamps.
*/
FITS_read_key(header, TSTRING, "INSTMODE", instmode, NULL, &status);
FITS_read_key(header, TFLOAT, "TTPERIOD", &ttperiod, NULL, &status);
/*
* Compute number of time stamps per second (0 for HIST data).
*/
if (!strncmp(instmode, "TTAG", 4)) /* TTAG MODE */
if (ttperiod > 1e-8) tstamps = 1./ttperiod;
else tstamps = 1.;
else /* HIST MODE */
tstamps = 0.;
/*
* Maximum IDS rate depends on instrument mode.
*/
FITS_read_key(header, TSTRING, "ELEC_CAL", elecfile, NULL, &status);
FITS_open_file(&elecfits, cf_cal_file(elecfile), READONLY, &status);
if (!strncmp(instmode, "TTAG", 4))
FITS_read_key(elecfits, TFLOAT, "TTAG_BUS", &max_ids_rate, NULL, &status);
else
FITS_read_key(elecfits, TFLOAT, "HIST_BUS", &max_ids_rate, NULL, &status);
FITS_close_file(elecfits, &status);
cf_verbose(4, "max_ids_rate = %f", max_ids_rate);
/*
* Calculate the IDS dead-time correction.
*/
for (k=0; k<nseconds; k++) {
ids_rate = aic_rate[k] + tstamps;
if (ids_rate > max_ids_rate)
ids_dtc[k] = ids_rate/max_ids_rate;
else
ids_dtc[k] = 1.0;
mean_ids_dtc += ids_dtc[k];
}
/*
* Write mean IDS dead-time correction to file header.
*/
mean_ids_dtc /= nseconds;
cf_verbose(2, "Mean IDS dead-time correction: %f", mean_ids_dtc);
FITS_update_key(header, TFLOAT, "IDS_DEAD", &mean_ids_dtc, NULL, &status);
cf_proc_update(header, CF_PRGM_ID, "COMPLETE");
cf_timestamp(CF_PRGM_ID, CF_VER_NUM, "Done processing");
return 0;
}
|
