Date post: | 12-Jan-2016 |
Category: |
Documents |
Upload: | kerry-dalton |
View: | 220 times |
Download: | 0 times |
2001 Mars Odyssey GRS1
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Early Mapping of Hydrogen,Potassium and Siliconfrom the Gamma lines
L. d’Uston, S. Maurice, O. Gasnault
2001 Mars Odyssey GRS2
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
8
104
2
3
4
5
678
105
2
3
4
5
678
106
2
3
4
Cou
nts
per
Cha
nnel
1400keV12001000800600400200Energy (keV)
#075m
Ge76
Ge(p,p'n)132.68 #1
46mSc
136.00
#265
Ga(spal)
~153.60
#371
As72
Ge(p,2n)181.52
#467
Ga70
Ge(p,a)190.39
#571m
Ge72
Ge(p,p'n)194.43
#6212
Pb235.75
#744m
Sc(spal)
269.56
#8214
Pb294.18
#967
Ga70
Ge(p,a)308.91
#10228
Ac337.10
#11214
Pb350.56
#1243
K43
Sc372.29
#1367
Ga70
Ge(p,a)402.69
#1423
Na69m
Zn(n,ng);spal
438.87
#1523
Mg450.71
#1624m
Na472.24
#177Be
(spal)477.17
#18annih
511.00
#1969
Ge70
Ge(p,p'n)584.02
#2074
Ge74
As(SAW)~598.00
#21214
Bi608.71
#2243
K617.39
#2663
Cu670.77
#2772
Ge72
Ge(n,n')~693.00
#2810
B719.02
#2958
Co(spal)
811.24
#3058
Co(spal)
817.97
#3172
Ge(SAW)~835.50
#3227
Al(843.8)27
Mg(844.01)56
Fe(846.7)~843.60
#3369
Ge70
Ge(p,p'n)882.65
#3446
Ti46
Sc889.55
#35228
Ac910.98
#3763
Cu962.50
#38228
Ac969.26
#3925
Mg974.81
#4048
Ti48
V48
Sc(n,ng)983.72
#4227
Al1014.65
#4345
Ar1021.10
#4448
Sc1038.20
#4566
Ga70
Ge(n,na)1048.95
#4668
Ga72
Ge(p,na)1087.00
#4769
Ge1107.00
#4869
Ge70
Ge(p,p'n)1117.70
#5065
Zn(Spal)
1124.50
#5144
Sc(Spal)
1157.00
#5260
Co1173.12
#5422
Na22
Ne1274.44
#5548
Ti48
V48
Sc1312.29
#5660
Co1332.94
#5769
Ge1346.68
#5824
MgAl
24Na
(n,ng)1368.58
#5952m
Mn(Spal)
~1434.30
#6040
K1460.78
2001 Mars Odyssey GRS3
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Gammas
Raw data from Query Tool (gammaspatial + engineering)
Time selection: Feb 20 – March 9
before annealing
Temperature selection: GRS_IS_TEMP_A < -165oC
2 weeks
55,972 spectra (~304 hours)
Neutrons
Press release data from W. Feldman & R. Tokar
Data sets
2001 Mars Odyssey GRS4
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
2001 Mars Odyssey GRS5
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
0.8
0.6
0.4
0.2
Cou
nts
/ min
/ ke
V
235023002250220021502100Energy (keV)
North (raw, >+75º)
South (bkg corrected, < -60º)
Middle (bkg corrected, > -60º, < +75º)
Al (2210)
H (2223)
2001 Mars Odyssey GRS6
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Energy callibration [W. Boyton, Feb 02]
Slope = 0.6152 keV/channel
Intercept = 18.86 keV
2.4 MeV
2.0 MeV
Continuum H-line
Background
2.215 – 2.230 MeV
Spectral Analysis
Energy
(cou
nts/
19.6
sec
)
2001 Mars Odyssey GRS7
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Min = 530 spectra
Mapping at 30o resolution (equal area)
(8)
(12)
(8)
(15)(12)
Application of the
Mapping/Display Toolkit
2001 Mars Odyssey GRS8
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Map of background
2001 Mars Odyssey GRS9
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Above +45o
Below –45o
Effects of atmospheric Absoption
Background with MOLA
2001 Mars Odyssey GRS10
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Map of background (corrected for 0 km MOLA altitude)
(same color range)
2001 Mars Odyssey GRS11
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Map above continuum H-LINE map
2001 Mars Odyssey GRS12
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Map of H-line (corrected for 0 km MOLA altitude)
2001 Mars Odyssey GRS13
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Smooth 4o
Epithermal neutrons [Press release data]
! Arb. Units = constant - epithermals !
2001 Mars Odyssey GRS14
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Epithermal neutrons: Rebin to 30o
2001 Mars Odyssey GRS15
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Correlation epithermals/gammas (1)
2001 Mars Odyssey GRS16
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Correlation epithermals/gammas (2)
2001 Mars Odyssey GRS17
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
• Map of HYDROGEN is feasible; it makes sense…
• Map of BACKGROUND:– Correlated with altitude (atmospheric effect)
– Corrected map shows signal at poles
• Agreement between epithermal neutrons & gamma H-line:– Very good at first order
– Strenghten epithermal detection of H
– Differences have not been interpreted
Conclusions
• Quantify statistical significance per pixel
• Increase surface resolution of gamma’s (15o by early May – 8o at poles)
• Use better epithermal map
• Incorporate HEND data ?
• Improve spectral analysis (norm to thermals / line fit…)
• Quantify gamma H-line Quantification of abundances
Future Developments
2001 Mars Odyssey GRS18
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
90N_60N 60N_30N 30N_00N 00S_30S 30S_60S 60S_90S
Co
un
ts p
er
Min
ute Mg 1369 keV
Ti 1382 keV
K 1461 keV
H 2223 keV
Si 1779 keV
Fe 7132 keV
Fe 847 keV
2001 Mars Odyssey GRS19
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
K line (1.461 MeV) underlying continuum versus MOLA altitude
Slope = 0.05 C/dt*km
Offset =4.045 C/dt
2001 Mars Odyssey GRS20
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Si line (1.779 MeV) underlying continuum versus MOLA altitude
Slope = 0.032C/dt*km
Offset = 2.885C/dt
2001 Mars Odyssey GRS21
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
2001 Mars Odyssey GRS22
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
2001 Mars Odyssey GRS23
Workshop HEND - 2002May 20th – 22nd 2002
Chemical elements preliminary mapping
Slope E-1.6
Atmospheric correction
I(h,E) = I0 exp (-α. g)
¤ α (E) attenuation coefficient in cm2/g
¤ g (h) optical thickness
in g/cm2
Using
ρ(h)= ρ0 exp (-h/10.8)