tips meeting – feb 21, 2002

February 21, 2002 TIPS meeting 1

"Data contained herein is exempt from ITAR regulations under CFR 125.4(13) -- data approved for public disclosure."

TIPS meeting – Feb 21, 2002

UVIS CCD IR FPA / Mux

WFC3 Status (detectors)M. Robberto



CCD Status

• Marconi has completed all deliveries.– Original order of 6 devices.

• One (# 23) damaged back in Nov 01 and returned to Marconi for analysis

• Four (# 18 & # 178 and # 37 & # 40) selected for flight and characterized.

• One held in reserve.

– Supplemental order of 2 devices.• Both (# 48 and #50) received, characterization of #38 underway in the

DCL.

– Closeout meeting held on 15 January 2002.

– Last detectors #37, #40, #50 shipped at Ball next week

• These are exceptional devices, with extremely uniform behavior from device to device.



WFC3 CCD Innovations

• Low readout noise.– Improves narrow-band and UV imaging sensitivity and enables shorter

sub-exposures in a long integration (providing more redundant images or more thorough drizzling).

– Will challenge the instrument electronics.

• High near-UV QE.– Major WFC3 scientific thrust is enabled.

• Extremely uniform detector spatial response.– Simplifies calibration and improves photometric accuracy.

• Charge injection for CTE degradation mitigation.– Slows down effective device aging.

• Fringing characterization and prediction for long wavelength observations.– Improves accuracy of narrow-band and narrow-line observations.



Marconi CCDs HaveVery Low & Consistent Readout Noise

Marc. DCL Marc. DCL Marc. DCL Marc. DCL Marc. DCL Marc. DCL

RN (A) e- 3 1.6 2.9 2.6 3 1.7 3.2 2.4 3.5 3.3

(B) e-3 1.7 1.8 2.6 2.9 1.6 3 1.6 3.5 3.6

Spec#165 #166#188 #152 #189

Units#187

Marc. DCL Marc. DCL Marc. DCL Marc. DCL Marc. DCL Marc. DCL Marc. DCL

RN (A) e- 3 3 3 2.2 3.1 <2.7 2.9 2.8 3.4 2.1 3.1

(B) e-3 3.5 3 2.3 3.1 <2.7 3 3.5 3.1 2.2 3.1

#040 #050Units Spec

#136 #178 #018 #023 #037

Read Noise For Marconi CCD43 Engineering Grade Devices

Read Noise For Marconi Flight Candidate Devices

By comparison, the SITe devices in the ACS instrument have read noises in the range 4.5-5.5 e-

Flight pair number 1 --- Flight pair number 2 candidates ---



Marconi CCDs Exceed Expectations for High UV QE

Pair Number 1 flight CCDs versus the Specification



IR-FPA Status

In addition, MUX #10 was delivered to Ball and is being integrated into the surrogate IR detector build

Detector# Produced Due Delivered Test report

11 13-Mar-01 9-Apr-01 27-Apr-01 26-Mar-01 pixel crosstalk14 30-Mar-01 23-Apr-01 27-Apr-01 10-May-01 pixel crosstalk15 18-Apr-01 23-Apr-01 16-May-01 30-May-01 QE non-uniformity at cutoff18 20-Apr-01 4-Jun-01 8-Jun-01 11-Jul-01 at Ball, integrated into qual unit20 20-May-01 4-Jun-01 8-Jun-01 18-Jul-0121 25-May-01 4-Jun-01 8-Jun-01 20-Jul-0122 13-Jun-01 6-Jul-01 18-Jul-01 1-Sep-0124 14-Jun-01 6-Jul-01 18-Jul-01 1-Sep-0125 6-Jul-01 6-Jul-01 18-Jul-01 1-Sep-01 warm image shows unbonded pixels27 19-Jul-01 3-Aug-01 7-Sep-01 15-Oct-01 Flight backup candidate30 1-Aug-01 3-Aug-01 7-Sep-01 8-Nov-01 Flight backup candidate31 23-Aug-01 3-Aug-01 12-Oct-01 1-Oct-01 Flight candidate32 4-Oct-01 4-Oct-01 26-Oct-01 8-Nov-0133 13-Sep-01 4-Oct-01 12-Oct-01 9-Nov-01 Flight candidate34 14-Oct-01 4-Oct-01 26-Oct-01 9-Nov-01

MILESTONESComments



Rockwell Test Results

Parameter Units 11 14 15 18 20 21 22 24

Gain e-/mV 361 300 321 315 274 315 315

Read noise e-/pix 65 40 47.2 47 39 43 47.5

Dark Current e-/pix/sec 0.5 0.6 0.049 0.34 0.37 0.104 0.388 0.357

Persistencee-/pix/sec

after 96 min 0.165 1.42 0.504

QE @ J % 72.7 27.9 24 20.6 42.7 32 45.2 47.1

QE @ 1.5 m % 86.1 31.2 27.1 33.8 64.6 44.4 58.8 50

Operability % >99 >97 >99 >99 >97 >97 >99.7 >99.1

Full Well ke->90 >85 >102 >100

FPA #

Parameter Units 25 27 30 31 32 33 34

Gain e-/mV 308 499 350 347 300 332 360

Read noise e-/pix 68.8 57.7 44.7 33.9 48.1 42.1

Dark Current e-/pix/sec 0.153 0.136 0.133 0.037 0.086 0.129 0.041

Persistencee-/pix/sec

after 96 min 0.499 0.207 0.43 0.067 0.083 0.125 0.055

QE @ J % 50.6 39 43.8 61.3 25.4 55.1 28.4

QE @ 1.5 m % 68.2 53.6 55.9 81.1 39.3 76 38.9

Operability % >99.2 >99.7 >99.8 >99.7 >99.7 >99.7 >99.6

Full Well ke->104 >150 >110 >100 >110 >100 >132

FPA #



RSC Dark Current and QE Results

The dark current and QE performance of the detectors showed dramatic improvement over the course of the program

min

100%

100%min



Dark current

y = 3E-17e0.2313x

0.0001

0.001

0.01

0.1

1

135 140 145 150 155 160 165

Temperature (K)

dark

cu

rren

t (e/

s)

FPA15:DC= 0.04e/s @ 150K

0.01

0.1

1

10

135 140 145 150 155 160 165

temperature (K)

dark

cur

rent

(e/s

)

0.01

0.1

1

10

144 146 148 150 152 154 156

temperature (K)

dark

cur

rent

(e/s

)

FPA22:DC= 0.39e/s @ 150K

FPA18:DC= 0.34e/s @ 150K



FPA310 7200s Exposure Dark Current vs Read Number

d07_150k_dk_00XX.fits

53000

54000

55000

56000

57000

58000

59000

1 3 5 7 9 11 13 15 17

Read Number

Mea

n S

ci P

ix (

DN

)

01

02

03

04

05

06

07

08

09

10

11

12

13

14

15

16

18

20

22

24

C. Hanley 11 Jan 2002

FPA31 dark current ramps

• Ramp slope decreases with time• Second read decreases with time

FPA31 10800s exposure



FPA31 M ean Signal in Last Read vs Time

53000

54000

55000

56000

57000

58000

59000

0 50000 100000 150000 200000 250000

Time (seconds)

Me

an

Sc

i Pix

(D

N)

1day 2days

FPA31 dark current settling time

Cycle power

A sequence of 20 ramps 3 hr long, each with 1+16 samples (one every 675s)



FPA31 Dark Current Over Time

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0 50000 100000 150000 200000 250000

Time (seconds)

Dar

k C

urre

nt (e

-/s)

FPA31 dark current settles after ~ 2 days

Cycle power

1day 2days

FPA31 dark current settling time

{CEIS



FPA31 dark anomaly

November 01 data

FPA31 appears to have two populations of pixels, each with their own dark current behavior.



FPA31 dark – 2 populations

October 24 data

1hr 1hr

1hr



Dark current summary

• FPA31 dark current is ~0.05e/s/pix, once the FPA is set.• Settling time is ~36 hr.• For the first ~36 hr the dark current is dominated by a

large drift in the output signal. • Irregular behavior still present after 36 hr on short ramps.• The drift is similar to the “reset anomaly”, but it has larger

time-scale and is related to the FPA power cycling. Reset anomaly can be corrected.

• Power cycling of IR FPA is not expected to routinely occur on WFC3.



Quantum efficiency

FPA31

January 11 data

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

500 700 900 1100 1300 1500 1700 1900

Q1

Q2

Q4

Q3

OK

$

$$



Readout noise

inboard

8

10

12

elec

tron

s

active area

SB Jan 16,2001

30

32

34

elec

tron

s

36



Readout noise

• FPA#15: 32 e/pix/read • FPA#18: 30 e/pix/read• FPA#22: 30 e/pix/read• FPA#25: 28 e/pix/read• FPA#31: 31 e/pix/read

Summary of the RON measured on active pixels



Reference pixels

4507 horizontal

1507 horizontal

1507 vertical

1014 5 reference pixels

1014 1014 active pixels

4507 vertical



Fixing reference pixels

0

5

10

15

20

25

30

35

40

45

50

0 6 12 18 24 30

Fowler DCS

adu Horizontal

Vertical

0ms 1ms 2ms 3ms 8ms

Vertical reference pixels are “light sensitive”Adding a delay time at the beginning of each line read eliminates the effect



Reference pixels drift in 60hr

45000

47000

49000

51000

53000

55000

57000

59000

0 50 100 150 200 250 300

sample

cou

nts

dark

vertical

horizontal

45900

45950

46000

46050

46100

46150

46200

0 50 100 150 200 250 300

sample

cou

nts

horizontal

vertical

Reference pixels are stable within ~100eover a time-scale of ~2.5 days



CONCLUSIONS

FPA 31 has been deeply investigated• QE above Performance Specs at m OK

below Minimum Specs at m NO

• Dark Current meets specs by a factor ~4, but– Needs ~ 36hr to settle ??– Irregular behavior common for short exposure times NO

• RON ~30 electrons/read NO

• Linearity and well depth OK

• Amplifier glow OK

• Cosmetic OK

• Reference pixels OK



• One between FPA#31 or FPA#33 to be delivered next week

• Rockwell has produced two extra non-flight parts, FPA#35, #36 currently under test. Preliminary data confirm QE and RON measured at DCL.

• Rockwell has delivered to UH (D. Hall) a detector with 5m material and HI-1R MUX for RON test.

• Rockwell has agreed to grow LOT 5. Expected 6-8 weeks for PECs/test device data and 4 months for flight parts.

• Contractual issues worked on.• New plan for 2nd detector build under discussion with

BALL.

tips meeting – feb 21, 2002

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