The soft X-ray experiment hardware and its operation are described. The device included six X-ray proportional counters, two of which, numbers 1 and 4, were pressurized with on-board methane gas supplies. Number 4 developed an excessive leak rate early in the mission and was turned off on 1975 day number 282 except for brief (typically 2-hour) periods up to day 585 after which it as left off. Counter 1 worked satisfactorily until 1975 day number 1095 (January 1, 1978) at which time the on-board methane supply was depleted. The other four counters were sealed and all except number 3 worked satisfactorily throughout the mission which terminated with permanent satellie shut-down on day 1369. This was the first large area thin-window, gas-flow X-ray detector to be flown in orbit. The background problems were severe and consumed a very large portion of the data analysis effort. These background problems were associated with the Earth's trapped electron belts

Kraushaar, W. L.

English

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https://ntrs.nasa.gov/search.jsp?R=19830005152 2020-03-21T05:24:11+00:00Z
iUniversity of Wisconsin-Madison
Department of Physics
Space Physics Laboratory
1150 University Avenue
Madison, Wisconsin 53705
Telephone: 6061262.5916
July 30, 1982
Contracting Officer
Code 209.4
NASA - Goddard Space Flight Center
Greenbelt, MD	 20771
To Whom it May Concern:
In accordance with Article XIV of NASA Contract NAS5-22 4 10, I
am submitting the required copies of the Final Report: OSO-8 Soft
X-Ray Wheel Experiment; Data Analysis.
Sincerely,
William L. Kraushaar
Principal Investigator
WLK:cje
Enc.
cc: Johr P. Roberts
i
Robert Perkl
Publication Branch, Code 251/
Patent Counsel, Code 204
NSSOC, Code 601
Dr. S. Maran, Code 683
Technical Officer, Code 440
f^
F ,c F,O
	
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NPSPS^SS a^e^ .:
( NASA
-CR-170448) ('SO-8 SOFT Y-HAY WHEEL
LXPLRISENT: DATA ANALYSIS Final Report
(Wisconsin Univ.) 15 p HC A02/NF A01
CSC L 148
N83-13423
unclas
G3/35 01608
3
SNASA CR =	
I
Final Report - OSO-8 Soft X-Ray 	 s
Wheel Experiment; Data Analysis
i
Contract No: NAS5.22410
I. Introduction
The soft X-ray experiment hardware and its operation is described
in the Final Report for Contract No: NAS5-11361 dated 10 August 1975.
The device included six X-ray proportional counters, two of which.
numbers 1 and 4, were pressurized with on-board methane gas supplies.
Number 4 developed an excessive leak rate early in the mission and
was turned off on 1975 day number 282 except for brief (typically
2-hour) periods up to day 585 after which it was left off.
Counter 1 worked satisfactorily until 1975 day number 1095
(January 1. 1978) at which time the on-board methane supply was
depleted. The other four counters were sealed and all except number
'i worked satisfactorily throughout the mission which terminated with
permanent satellite shut-down on day 1369. Counter 3 had some sort of
electrical leakage problem that appeared to develop as a result of
launch. It never operated correctl y in orbit.
This was the first large area thin-window. gas-flow X-ray detector
to be flown in orbit. The background problems were severe and con-
sumed a very large portion of the data analysis effort. These back-
ground problems were associated with the earth's trapped electron belts.
The ; deal orbit for experiments of this type is equatorial-low altitude.
II. Data Tapes Supplied to NSSDC
All production data tapes have been received from GSFC and have been
processed. Each record of the resulting "reduced" data contains all of
the basic usable information obtained from the experiment in a 20.48
second time interval, along with the position, attitude and equipment
performance information needed to analyze the data in an independent
fashion. The format of these tapes is specified on the accompanying
pages labeled "Science Data Record Definition." One complete set of
reduced data tapes, 150 in all, have been set to NSSDC, as well as the
32 tapes described below.
The next step in the data reduction was the creation of a set of
23 "compressed" data tapes. The compressed tapes are written in the
same format as the reduced data, but data recortis were eliminated for
times during satellite da} and for other times when there was reason to
believe that the data were invalid or contaminated. The compressed
tapes contain all valid data from both methane counters (as well as
sealed counter data from those times), including earth-looking and
calibration data.
A further step in the data reduction produced a st, zf 8 'FWD-GOOD"
tapes, containing data records from times when counter 1 was sky-looking
and yielding valid, unccntaminated data, Times were eliminated when
strong sources (count rate 2 4 cts s -1 ) were in the field of view. Each
record contains data from a single 20.48 second time interval and is
i*i the same format as the reduced data.
The final step in the data reduction was the creation of the
"SUMFWD" tape. Each of the 1400 records on this tape is the composite
of all of the "FWD-GOOD" records contained in each time interval that
the counter 1 field of view moved 1' along the scan path. Data taken
when the angle between the look direction and the earth's magnetic field
vector was between 70° and 110° were eliminated. The format for these
records is the same as for the reduced data, except that various
quantities have been su=ed or averaged as appropriate.
OSO-8 SOFT X-RAY EXPERIMENT (WISCONSIN)
SCIENCE DATA RECORD DEFINITION
General Information
1) The science data records (SDRs) are written on unlabeled 9-track
tapes at 1600 bpi, odd parity.
2) The tapes were written by a Univac 1110. All words are 36 bits, packed
4 112 8-bit bytes per word. Real numbers are written in Univac 1100
series floating point format.
3) Each file contains
a) Less than 43200 seconds of data on the "reduced" data tapes. In
addition, the direction of the spin axis is within 10° of its
direction at the start of the file.
b) 8 days of data on the "compressed" data tapes
c) 50 days of data on the "FWD-GOOD" data tapes
4) Each physical record contains 10 logical records. Each logical record
(SDR) contains all the X-ray data collected in one 20.48 second
telemetry frame, along with the experiment status and satellite status
and orientation information necessary for analysis of the X-ray data.
Each logical record contains 300 words whose contents are described in
the following pages.
5) logical records on any tape are always in ascending time order.
6) All angles are in degrees.
7) The RA of the local earth magnetic field vector (SDR word 243) is
sometimes wrong on some of the "reduced" data tapes from days before
-.800.
8) More information can be found in the OSn-8 Soft X-ray Experiment
(Wisc,)nsin) Final Report.
-2-
OSO-8 SOFT X-RAY EXPERIMENT (WISCONSIN)
SCIENCE DATA RECORD DEFINITION
Word Type Description
1 Integer ID word (1010
 in the 12 MSB)
2 Integer FLAG word (see p.
	 3)
3 Real Day of year 1975
4 Real Seconds of day of start of data record
5-204 Real Count rate data (see p.
	
7)
205-214 Integer Digital subcom words	 (see FINAL REPORT, p.	 53)
215-220 Integer HVPS 1-6 monitors (see FINAL REPORT, p.	 55)
221-222 Real RA, DEC of center of FOV of sector CLR
223-238 Real RA, DEC of center of FOV of sectors 0-7
239-240 Real Satellite geodetic latitude, east longitude
241-242 Real McIlwain L and B parameters
243-2244 Real RA,	 DEC of earth's magnetic field vector
245-246 Real Zenith and azimuth angles of the Sun
247-264 Real Zenith and azimuth angles of the center of the
field of view of sectors CLR, 0-7
65 Real Satellite altitude
266-277 Real Total	 rates and deadtimes (see p. 	 8)
278 Real Zenith angle of horizon + 160 km of atmosphere
279-284 Real Most recent calibrate ratios for counters 1-6
285-286 Real RA,	 DEC of satellite roll axis
287-289 Integer HV relay monitors
	
(see FINAL REPORT, p. 	 55)
290 Real Satellite spin	 rate (RPM)
291 Real FLAGS2 word (see p. 5)
292-294 Real GSUM,	 HIENGY, AFTVETO (see p.
	
9)
295-299 Used only on FWDSUM tape (see p.
	
9)
300 Integer Checksum:
	 XOR of SDR words 1-299
-3-
OSO-8 SOFT X-RAY EXPERIf*ENT (WISCONSIN)
SCIENCE DATA RECORD DEFINITION
FLAG (SDR Word 2)
Bit Description
0 (MSB) attitude computation type (1	 = coarse, 0 = fine)
1 = 1 if	 HIENGY>100 counts
2 = 1 if 80<HIENGY<99 counts
3 = 1 if 70<HIENGY<79 counts
4 =	 ' if 53<HIENGY<69 counts
5 = 1 if 41<HIENGY<52 counts
6 = 1 if	 0<HIENGY<40 counts
If HIENGY <O, bits 1-6 are all	 = 1
7-9 Number of bit errors in minor frame synch words for
count data in this major frame.
	
If >7, set to 7
10 = 1 if fill	 data present in this frame
11 = 1 if it was impossible to check for a HVPS on/off
transition between this and an adjacent frame
for counters 1	 and 4 (cf. bit 35)
12 = 1 if the day/night override is ON
13 = 1 if this is a calibrate frame and an overflow
correction was made
14 = 1 if this is a valid calibration frame
15 = 1 if this is a calibrate turn-on frame (next frame
will be a valid calibrate frame)
-4-
FLAG (SDR Word 2) (continued)
Bit Description
16 - 1 if this is a calibrate turn-off frame (previous frame was
a valid calibrate frame)
17 = 1 if any HVPS turned off or on between this frame
and an adjacent one
18 = 1 if any non-gas-flow HVPS turned off or on between
this frame and an adjacent one
19 = 1 if this is dwell mode data or some other glitch
20 = 1 if the radiation monitor override is ON
21 = 1 if spacecraft sun sensor indicates DAYTIME
22 = 1 if either adjacent frame is missing
23 = 1 if the previous frame is missing
24 = 1 if 1 or more ratemeters high
25 = 1 if buffer volume valve is open
26 = 1 if there are 1 or more sclenoid 1 counts
27 = 1 if there are 1 or more solenoid 2 counts
28 = 1 if this frame fails any of ti10 internal consistency checks
29 - 1 if VHF transmitters are ON
30 = 1 if S-Band transmitters are ON
31 = 1 if this is a day of high geomagnetic activity
32 = 1 if suspect an extra MIP
33 = 1 if this is a self test frame
34 = 1 if illegal	 non-D/S data present
35 = 1 if it was impossible to check for a HVPS on/off
transition between this and an adjacent frame
for any counter (cf. bit 11)
3
NOTE: the quantity HIENGY is defined on p. 9.
-5-
OSO-8 SOFT X-RAY EXPERIMENT (WISCONSIN)
SCIENCE DATA RECORD DEFINITION
FLAGS2 (SDR Word 291)
Bit
0 = 1 if the RA of the earth's magnetic field has been corrected
1-15 not used
16 - 1 if orbit predictions indicate NIGHT
17 = 1 if satellite :n geographic region 3 -usually bad data
18 = 1 if satellite in geographic region 2 -possibly bad data
19 = 1 if satellite in geographic region 1	 - possibly good data
20 = 1 if satelli ce in geograprt.-	 re g ion 0 - probably good data
If the geographic region calculation was impossible
to do,	 bits 17-20 are all	 = 1.
21 - 1 if	 AFTVETO>6000 cts/s
22 1 if 4400<AFTVETO<6000 cts/s
23 = 1 if 3300<AFTVETO<4399 cts/s
24 1 if 2001<AFTVETO<3299 cts/s
25 1 if -1000<AFTVETO<2000 cts/s
If the calculated AFTVETO WAS LESS 1HAN -1000 cts/s,
bits
	
21-25 are all
	 =1.
26 = 1 if	 GSUM>1000 counts
27 = 1 if 501<GSUM<1000 counts
28 = 1 :f 301<GSUM<500 counts
29 - 1 if 271<GSUM<300 counts
-6-
FLAGS2 (SDR Word 291 (continued)
Bit Description
30 - 1 if 241<GSUM<270 counts
31 = 1 if 213<GSUM<240 counts
32 = 1 if l5 k GSUM<212 counts
33 = 1 if 136<GSUM<150 counts
34 - 1 if 1<GSUM<135 counts
If GSUM = 0. bits 26-34 all n 0.
If GSUM <0. bits 26-34 all n 1.
35	 1 if a satellite attitude gas firing occu--s
Notes: 1) This floating point real number (SDR word 291) must be set
equal to an integer type variable for this description to
be valid.
2) The four geographic regions referred to in the description
of bits 17-20 are defined by the three contours of Figure 2
of Bunner (1978, Ap ; J_. J,0, 261)
3) AFTVETO and GSUM are quantities defined on p. 9.
f
f
s
-7-
OSO-8 SOFT X-RAY EXPERIMENT (WISCONSIN)
SCIENCE DATA RECORD DEFINITION
Count Rate Data (SDR Words 5404
Word Type Description
5 Real 255.(Synch word)
6, 9 Re.l Sail	 position (twice)
7, 8 Real Data system status word (twice)
10,	 it Real 0.	 (twice)
12-171 Real Counts array:	 DATA(CHANNEL,SECTOR)
where CHANNEL goes from 1 to 16
and SECTOR from 0 to 7, CLR, BKG
172-201 Real Active times array:	 TIME(COUNTER,SECTOR)
where COUNTER goes from 1 tc 3
and SECTOR from 0 to 7, CLR, BKG
(The unit of active time is 0.2 seconds for
sectors 0-7 and 0.4 seconds for sectors
CLR and BKG.)
2C2-203 Real Mett,ane counter gas flow solenoid firings -
for counter 1, counter 4.
204 Real 0.
Note: These numbers are minor frame words 49 and 50 from telemetry channels
0 through 99, described in Table 5-5 of the FINAL REPORT, p. 60.
qu
-o-
OSO-8 SOFT X-RAY EXPERIMENT (WISCONSIN)
SCIEK E DATA RECORD DEFINITION
Total Rates and Deadtimes (SDR Words 266-277)
Word Type Description
266 Real Counter 4 (aft methane) total 	 rate
267 Real Counter 5 (aft neon) total rate
268 Real Counter 6 (aft xenon) total rate
269 Real Counter 1	 (forward methane) total rate
270 Real Counter 2 (forward neon) total gate
271 Real Aft counters (4+5+6) total 	 rate
272 Real Forward counters (1+2) total rate
273 Real AFT ATMAX-maximum possible AFT active time (1006-1024)
274 Real CLR AT:lAX-maximum possible CLR active time (211-320)
275 Real Aft counter 4 active time deficit
276 Real Aft total active time deficit
277 Real CLR active time deficit
Note: For each frame we calculate from the satellite spin rate and sail
position what the maximum active times could have been (if the
high voltages were off) for the AFT (0-7) sectors and the CLR sector.
From the observed active times, we get. active time "deficits" for each
sector and counter, and we can calculate from that what the total
rates W-ray events + vetoed events) were.
1, -9-
OSO-8 SOFT X-RAY EXPERIMENT (WISCONSIN)
SCIENCE DATA RECORD DEFINITION
Miscellaneous (SDR Words 291-299)
Word Yffe Description
292 heal G-SUM is the sum of SDR words 12 -171.	 This
sum is the total number of counts recorded
in all energy channels and all 	 sectors.
293 Real HIENGY is the sum of the counts recorded in
channels 15 and 16 in sectors 0-7.
294 Real VETO - AFVETO - AFT VETO is an estimate of the
veto rate for the aft counters (4+5+6)
determined by subtracting the measured X-rAy
count rate from the calculated total count
rate (SDR word 271) for the aft counters.
295 Real SCANANGLE is the cumulative angle along the scan
path of the current logical	 record (FWDSLM
only).
296 Real LASTDAY is the day of the last frame included
in the current logical	 record (FWDSUM only).
297 keal LASTSEC is the time of day, in seconds, of the
l ast frame included in the current logical
record (FWDSUM only).
298 Integer SRCFLG bits are set corresponding to the energy
channels in which counts from a known X-ray
source in the field of view are expected: 	 bit 0
for channel	 1, bit 1	 fur channel 2, etc.	 (FWDSUM
only).
299 Integer Number of frames included in this logical 	 record
(FWDSUM only) .
III. Nublications - Talks
PUBLICATIONS
"V843 Ophiuchi Supernova Remnant," A. N. Bunner, IAU Circular #3339,
23 March 1979.
"X-Rays from Kepler's Supernova," A. N. Bunner, Sky and Telescope, page 430,
May 1979.
"First Coordinated Campaign of X-Ray and Ground Based Observatior,s of
X Persei = 3UO352+30," C. deLoore et al., Astron, b Astrophys., 78,
287 (1979).
"Some Components of the Diffuse Soft X-Ray Background," Masaru Matsuoka,
ISAS Research Note, Institute of Space and Aeronautical Science,
University of Tokyo.
"Spatial Structure in the Soft X-Ray Background as observed from OSO-8,
and the North Polar Spur as a Reheated Su pernova Remnant," R. J.
Borken and DeAnn Iwan, Ap.J., 218, 511 (1977).
"Soft X-Ray Results from the Wisconsin Expr.riment on OSO-8," A. N. Bunner,
Ap.J. 219, February 15, 1978.
"Coaxial Anode for Background Suppression in X-Ray Proportional Counters,"
A. N. Burner, W. L. Kraushaar, D. McCammon, M. Vanderhill, and
F. Williamson, The Rev. of Sci. Instr., Vol. 44, No. 4, April 1973.
"Detection of Sof,. X-Ray Emission from SMC X-1," A. N. Bunner and W. T.
Sanders, Ap.J. 228, L19 (1979).
"On the Lack of AbForption of 1 keV Diffuse X-Rays by the Small Magellanic
Cloud," A. N. Bunner, W. T. Sanders and J. A. Nousek, Ap.J. 228, L29,
February 15, "1179.
"X-Ray Obser • itions of the North Polar Spur," DeAnn Iwan, Ap.J. 239, 316
TALKS
i
"Two New Variable Soft X-Ray Sources in the Southern Sky," A. N. Runner and
W. T. Sanders, 153rd Meeting of the A.A.S., Mexico City, January 19?9.
"OSO-A Observations of the Soft X-Ray Diffur.e Rockground," W. T. Sanders,
A. N. Runner and W. L. Kraushaar, ISIrd Meeting of the A.A.S., Mexico
City, iantory 1919.
"An Unusual X-Ray T^ansient Observed with OSO-A," P. Serlemitsos, A. N.
Runner, J. H. Swank, Suring Meeting of the Am@rican Physkal Society,
Washingte . April 1919.
"A New Soft X-Ray Somv p in Hydra," A. N. Runner, Spring Meeting of the
American Physical Society, Washington, Aliril 1419,
"X-Rays from the Kepler Suprrnova Rimnant." A. N. Runner, 154th Mrrtinu of
the A.A.S., Wellesley. June 11419.
"Came Components of lliff(Ixe Soft X-Rays." Mamoru N,it`uoka, f1st.,krnomical
society of ,lalmn. M.'v 4-1: , 14711, Tokyo,
"observation of Satt X Ray fmissiov frA)m SMC. X-1," A. N. Runner, W. T,
Sanders. J. A. Nousek. and W. L. kraushaar. 1',4nd Mooting of the A.A.S.,
Madison. June 141P.
"An Upper limit to :he Ahsorption of 1 ke-V Diffvif X-Rays by the Small
Mayetlanir Cloud," A. N. Runner. W. T. rmovrs, W. t . kvmmt ar, and
J. A. Noumek. P)."'nd ';ee-ting of the A.A.S„ M,1,timan. June 141A.
"X-Ray Observations of thr- Nor th Prrlar Spur," D. C. swan, IS.'nrt Nr;7tinQ
of the A.A.S.. Madison. June ;918.
"Soft X-RAY Source 511e(tra from 0c0-8," A, N, Runner, prexented at. 11.1 .A,O,
meeting of VA.S,, Cambridge. Massachu%ettc, ,)Amory .9. 1416.
M* S, VOIAt
"tow rnargy Qbxarvatilim of tho tare NaV1lAnir Cloud from t1SO-a,"
A. J. Aurkan, ara<rrntad at. HA A,D, moot ing of AAA,, CamMA490, N14,44
January M. 14M.
"Sett xxAAy Sturvo 5tuMoW A. W Gunnar, prr antari At VVS, mooting,
4avor(ord. PA, Tuna N. 1016,
L


OSO-8 soft X-ray wheel experiment: Data analysis

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