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LYRA SWENET intro

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Tested separately to find transmittance and responsivity. Simulated with TIMED-SEE solar ... Relevant spectral range is tested, with special attention to range borders ... – PowerPoint PPT presentation

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Title: LYRA SWENET intro


1
LYRA the Lyman-alpha Radiometer onboard PROBA-2
LYRA Tests and Selections
SCSL Meeting Bern 29 Nov - 01 Dec 2006
2
Contents
  • I. From Model to Configuration
  • II. BESSY Campaigns
  • a. Flux Linearity
  • b. Stability, Drift
  • c. LEDs, Dark Current
  • d. Spectral Responsivity
  • e. Homogeneity, Flatfield
  • III. Summary

3
I. From Model to Configuration
  • Choice of filters Zirconium (150 nm, 300 nm),
    Aluminium, Lyman-alpha (N, XN, VN, and
    combinations thereof), Herzberg,
  • Choice of detectors MSMxx (diamond), PINxx
    (diamond), AXUVxx (silicon),
  • Tested separately to find transmittance and
    responsivity
  • Simulated with TIMED-SEE solar spectra to find
    expected response values and purities
  • cf. http//lyra.oma.be/radiometric_model/radiometr
    ic_model.php
  • Example high flux Herzberg filter PIN
    detector

4
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5
Selected configurations
  • filter detector nominal FWHM measured
  • 1-1 Ly XN MSM12 121.5 /- nm 116-126 nm
  • 1-2 Herzberg PIN10 200-220 nm 197-218 nm
  • 1-3 Aluminium MSM11 17-80 nm (1)-2.4, 17-35
    nm
  • 1-4 Zr (300nm) AXUV20D 1-20 nm (1)-1.3, 6-15
    nm
  • 2-1 Ly XN MSM21 121.5 /- nm 116-126 nm
  • 2-2 Herzberg PIN11 200-220 nm 199-219 nm
  • 2-3 Aluminium MSM15 17-80 nm (1)-1.4, 17-27
    nm
  • 2-4 Zr (150nm) MSM19 1-20 nm (1)-1.3, 6-12
    nm
  • 3-1 Ly NXN AXUV20A 121.5 /- nm 116-126 nm
  • 3-2 Herzberg PIN12 200-220 nm 198-219 nm
  • 3-3 Aluminium AXUV20B 17-80 nm (1)-2.4, 17-35
    nm
  • 3-4 Zr (300nm) AXUV20C 1-20 nm (1)-1.3, 6-15
    nm

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7
Consequence
  • All channels individual
  • No simple redundancy
  • Combined responsivities
  • New estimates for response and purity (cf. II d.)

8
II. BESSY Campaigns
  • NI beamline (40 240 nm, 60 C) July 2005
  • Doc. RP-ROB-LYR-0132-NI-July2005
  • GI beamline (1 30 nm, 60 C) July 2005
  • Doc. RP-ROB-LYR-0132-GI-July2005
  • (Final) NI beamline (40 240 nm, 37 C) March
    2006
  • Doc. RP-ROB-LYR-0132-NI-March2006
  • (Final) GI beamline (1 30 nm, 37 C) March 2006
  • Doc. RP-ROB-LYR-0132-GI-March2006

9
a. Flux Linearity
  • Using different aperture stops, or
  • Varying exit slit of monochromator
  • Relation fitted (2006) with a function
    IcaPb
  • Results almost linear, slightly sub/superlinear,
    sub/superlinear (qualitatively)
  • or b1, c0 (quantitatively)

10
Results in detail
  • NI 2006 GI 2005 NI 2006 GI 2006
  • (121.6 nm, 200 nm) (20 nm, 10 nm)
    (121.6 nm, 210 nm, 50 nm) (18 nm,
    10 nm)
  • 1-1 MSM slightly sublin. 0.99572
  • 1-2 PIN slightly superlin. 1.00656
  • 1-3 MSM 0.98565 1.1719, but cgt0
  • 1-4 AXUV 1.00155
  • 2-1 MSM slightly sublin. 1.03661
  • 2-2 PIN slightly superlin. 0.99483
  • 2-3 MSM superlinear 1.02234 0.97894
  • 2-4 MSM slightly superlin. 1.04009
  • 3-1 AXUV almost linear 1.02434
  • 3-2 PIN almost linear 0.99529
  • 3-3 AXUV sublinear 0.00230 0.99253
  • 3-4 AXUV almost linear 1.00064

11
b. Stability, Drift
  • Shutter was opened and closed every 60 s, then
    every 600 s
  • Some additional longer tests were executed
  • BESSY 2005 campaigns (60 C) still to be analyzed
    in detail
  • LED values, dark current values and 44 C, 50 C
    temperature effects see below
  • Example
  • Channel 2-1 (Ly XN MSM21) at BESSY NI 2006

12
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13
Results (2006) in detail
  • start drift stop
  • (slow min, almost
    immediate s)
    (tail min, almost immediate s)
  • 1-1 MSM slow upward tail
  • 1-2 PIN almost immediate (almost) no almost
    immediate
  • 1-3 MSM almost immediate, slow upward tail,
    almost immediate
  • 1-4 AXUV immediate no immediate
  • 2-1 MSM slow upward tail
  • 2-2 PIN almost immediate (almost)
    no immediate
  • 2-3 MSM slow upward almost immediate
  • 2-4 MSM slow upward almost immediate
  • 3-1 AXUV (almost) immediate (almost) no almost
    immediate
  • 3-2 PIN almost immediate no immediate
  • 3-3 AXUV (almost) immediate (almost)
    no (almost) immediate
  • 3-4 AXUV immediate no almost immediate

14
c. LEDs, Dark Current
  • visLED uvLED offset _at_37 C 44 C 50
    C
  • 1-1 MSM (0.005) (0.024) 0.001 0.010
  • 1-2 PIN 0.004 0.014 0.000 -0.002
  • 1-3 MSM (0.100) 0.000, -0.007 0.003 0.010
  • 1-4 AXUV -0.004
  • 2-1 MSM (0.012) (0.023) 0.001 0.009
  • 2-2 PIN 0.015 -0.001 -0.002 -0.005
  • 2-3 MSM ((0.016-0.136)) 0.000, -0.008
    0.002 0.007
  • 2-4 MSM -0.001
  • 3-1 AXUV 0.000? 0.000 0.002 0.008
  • 3-2 PIN 0.006 -0.003 -0.005
  • 3-3 AXUV (1.059) -0.001, -0.011
    -0.003 -0.005
  • 3-4 AXUV -0.014
  • All values in nA
  • (x) varying around x, ((x-y)) unstable from y
    to x, negative current values due to conversion

15
d. Spectral Responsivity
  • Filters and detectors measured together
    (channels as configurated)
  • Relevant spectral range is tested, with special
    attention to range borders
  • V changed to A using appropriate gain resistor
  • Corrections for ring current applied
  • Example high solar flux simulated with
    measurements of channel 1-1 (Ly XN MSM12) at
    BESSY NI 2006
  • How to estimate correction factors?
  • Consequences for data levels?

16
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17
Expected Signal and Purity
  • theorectical min high measured
    min high
  • 1-1 MSM 0.139 nA (37) 0.161 nA (44)
    0.240 nA (24) 0.267 nA (30)
  • 1-2 PIN 12.75 nA (86) 12.77nA (86)
    12.57 nA (83) 12.59 nA (83)
  • 1-3 MSM 0.120 nA (61) 5.264 nA ( 3)
    0.086 nA (58) 4.945 nA ( 3)
  • 1-4 AXUV 0.530 nA (99) 15.37 nA (88) 0.699
    nA (100) 19.09 nA (100)
  • 2-1 MSM 0.115 nA (39) 0.135 nA (46)
    0.104 nA (21) 0.114 nA (26)
  • 2-2 PIN 13.80 nA (83) 13.82 nA (83)
    13.75 nA (84) 13.76 nA (84)
  • 2-3 MSM 0.127 nA (73) 3.821 nA ( 6)
    0.074 nA (59) 3.837 nA ( 3)
  • 2-4 MSM 0.111 nA (99) 2.878 nA (100)
    0.094 nA (100) 2.772 nA (100)
  • 3-1 AXUV 0.132 nA (46) 0.156 nA (54) 0.113
    nA (81) 0.148 nA (84)
  • 3-2 PIN 10.20 nA (85) 10.22 nA (85)
    10.15 nA (83) 10.16 nA (83)
  • 3-3 AXUV 1.072 nA (75) 34.95 nA ( 6) 1.090
    nA (72) 36.83 nA ( 5)
  • 3-4 AXUV 0.530 nA (99) 15.37 nA (88) 0.710
    nA (100) 19.31 nA (100)

18
Calibration Factor, Data Levels
  • How to estimate the solar signal from the LYRA
    signal?
  • LYRA signal purity / area / responsivity
    solar signal
  • A m2 A W-1
    W m-2
  • \___________________/
  • calibration factor
  • Example max, high, min flux Channels
    1-1, 1-2, 1-3, 1-4
  • Use constant factor, linear dependency on signal,
    knowledge about solar flux?
  • Change public data each time when calibration
    factor gets more realistic? Use different data
    levels?

19
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20
e. Homogeneity, Flatfield
  • Example Channel 2-3 (detector diameter 4.2 mm)
  • What consequences will an off-pointing have?

21
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22
III. Summary
  • Linearity Stability LEDs
    Signal, Purity
  • 1-1 MSM -- -
  • 1-2 PIN
  • 1-3 MSM --- - ? --
  • 1-4 AXUV ??
  • 2-1 MSM - -
  • 2-2 PIN
  • 2-3 MSM -- - -? --
  • 2-4 MSM - ??
  • 3-1 AXUV -
  • 3-2 PIN ?
  • 3-3 AXUV - ? --
  • 3-4 AXUV ??

23
Recommendation
  • Head 2 should be nominal
  • Head 1 should be used once a week
  • Head 3 should be used once a month
  • depending on the behaviour of LYRA (deterioration
    etc.)
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