uv led quality test
DESCRIPTION
UV LED quality test. All 872 UV LEDs tested Selection is about to finish. Jaroslav Zalesak Institute of Physics ASCR, Prague. Measurement setup. LED Driver pulses – UV LED – opt. fibers – APD – preamp – scope Measured by scope of 4 channels/fibers for each LED (semi-automatic procedure) - PowerPoint PPT PresentationTRANSCRIPT
May 11, 2006 CALICE Collaboration Meeting, McGill Uni, Montréal, Québec, CA
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UV LED quality testUV LED quality test
All 872 UV LEDs tested Selection is about to finish
Jaroslav Zalesak Institute of Physics ASCR, Prague
May 11, 2006 CALICE Collaboration Meeting, McGill Uni, Montréal, Québec, CA
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•LED Driver pulses – UV LED – opt. fibers – APD – preamp – scope •Measured by scope of 4 channels/fibers for each LED (semi-automatic procedure)•@ different positions (diff radius: 0.58, 1.15, 1.76 mm) wrt. central LED point
54
3 2
1
8
7
6
910
11
12
Light source asymmetric wrt. LED central point
Phi response variations
Zero angle position uncertainty
reproducibility 5%
Measurement setupMeasurement setup
May 11, 2006 CALICE Collaboration Meeting, McGill Uni, Montréal, Québec, CA
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Angle Anisotropy
0.000E+00
5.000E-09
1.000E-08
1.500E-08
2.000E-08
2.500E-08
3.000E-08
3.500E-08
0 60 120 180 240 300 360
Theta
Are
a
fibre 11 fibre 3 fibre 6 fibre 8 sum
Linearity
0.00E+00
5.00E-09
1.00E-08
1.50E-08
2.00E-08
2.50E-08
3.00E-08
2.800 3.300 3.800 4.300 4.800
LV [V]
Area
[Vs]
fiber 11 fiber 3 fiber 6 fiber 8 SUM / N_fib
Temperature Dependence
0.1500
0.1700
0.1900
0.2100
0.2300
0.2500
0.2700
0.2900
0.3100
0.3300
0.3500
299.5 300.0 300.5 301.0 301.5 302.0 302.5 303.0 303.5
Temp [K]
Am
pl [
V]
fiber 11 fiber 3 fiber 6 fiber 8 SUM / N_fib fit 11 fit 3 fit 6 fit 8 fit sum
2-3% Temperature correctionchange of APG gain (10) w/ T
Zero position setup uncertainty
Good linearity behavior
UV LED (400nm) characteristicsUV LED (400nm) characteristics
May 11, 2006 CALICE Collaboration Meeting, McGill Uni, Montréal, Québec, CA
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Temp corrected Calibrated Area
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
300 400 500 600 700 800 900 1000 1100
LED #
Are
a [n
Vs]
fiber 11 fiber 3 fiber 6 fiber 8 Tcorr Calib SUM
UV LEDs Response – full sample 872 LEDs (I)UV LEDs Response – full sample 872 LEDs (I)
after light calibration and temperature corrections
May 11, 2006 CALICE Collaboration Meeting, McGill Uni, Montréal, Québec, CA
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Different SUMs
0.50
0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
1.40
1.50
300 400 500 600 700 800 900 1000 1100
LED #
Rel
ativ
e A
rea
norm SUM SUM * Tcorr Tcorr Calib SUM Temp
-2 K
UV LEDs Response – full sample 872 LEDs (II)UV LEDs Response – full sample 872 LEDs (II)
+2 K
response normalized to the average over all LEDs (summed up all fibers) visible decrease of response for beginning of data taking but not correlated with LEDs themselves
Temp
CT = 1 - 0.1 * (T-To)
May 11, 2006 CALICE Collaboration Meeting, McGill Uni, Montréal, Québec, CA
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Time Dependence LED# 230
0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
1.40
0.0 10.0 20.0 30.0 40.0 50.0
Time [Days]
No
rm A
rea
fiber 11 fiber 3 fiber 6 fiber 8 Tcorr Cal SUM
Time Dependence LED# 639
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
25.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0 65.0
Time [Days]
No
rm
Area
fiber 11 fiber 3 fiber 6 fiber 8 Tcorr Cal SUM
• middle time stability: RMS 5% (reproducibility)• short time stability: 1.5-2% LED w/o touching (= statistics)
Single LED time stabilitySingle LED time stability
• long time stability: over 20% decrease of fiber light response
May 11, 2006 CALICE Collaboration Meeting, McGill Uni, Montréal, Québec, CA
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Time dependence - Temp Corr Calib Area
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
0.0 10.0 20.0 30.0 40.0 50.0 60.0
Time [Days]
Are
a [n
Vs]
Fiber 11 Fiber 3 Fiber 6 Fiber 8
Study of time stabilityStudy of time stability to be correctedto be corrected divide into 2 parts: Y= A + B * (x-x0) [slope] Y= A for x>x0 [const] fit 3 parameters: A,B and break point x0
vary for each fiber
Preliminary:
break points are similar 650±40 day 30
fiber 3 fiber 11
May 11, 2006 CALICE Collaboration Meeting, McGill Uni, Montréal, Québec, CA
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LED# 640-1179 (532pcs)
0
10
20
30
40
50
60
70
80
90
100
unde
r0.
500.
600.
700.
800.
901.
001.
101.
201.
301.
401.
50
Selection criteriaSelection criteria
LED # koef 100% ± 20 % ± 15 % ± 10 % ± 5 %RMS 1.5 1.35 1.22 1.11
all 1.000 872 773 650 498 26013.1% 100.0% 88.6% 74.5% 57.1% 29.8%
640--1179 0.955 532 498 434 309 17612.7% 100.0% 93.6% 81.6% 58.1% 33.1%
= 12.7%
Preliminary: only “constant” part i.e. 532 LEDs
within range of ±15% 82% of LEDs RMS = 13%
additional (redundant) criteria: variation range for each fiber
May 11, 2006 CALICE Collaboration Meeting, McGill Uni, Montréal, Québec, CA
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ConclusionConclusion
All UV LEDs (872 in our hands) were tested
“no name” leds look reasonable! in general: LED light emission show same characteristics similar behavior
decrease of response @ first measured leds is probably due to instability of the measured equipment (aging,..) than degradation of light of LEDs themselves apply correction for each channel/fiber with function of const + slope line main selection criterion based on led light variation being within range ± 15% in ‘const’ sub-sample of 532 leds 82% satisfied 1.35 highest/lowest emission
for entire LED system the PINs watch of LED response important to keep its time and temperature stability distribution of one LED light into single fibers (up to 100% of lowest->highest yield) rather important than overall variation of light among leds