slide1
Download
Skip this Video
Download Presentation
Overview

Loading in 2 Seconds...

play fullscreen
1 / 54

Overview - PowerPoint PPT Presentation


  • 123 Views
  • Uploaded on

Performance and evaluation of large format 2Kx2K MBE grown HgCdTe Hawaii-2RG arrays operating in 32-channel mode G. Finger, R. J. Dorn, M. Meyer, L. Mehrgan, J. Stegmeier, A.F.M. Moorwood. Overview. Set-up 32 channel package using CMOS cryo-opamps instead of ASIC’s

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Overview' - sheng


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Performance and evaluation of large format 2Kx2K MBE grown HgCdTe Hawaii-2RG arrays operating in 32-channel modeG. Finger, R. J. Dorn, M. Meyer, L. Mehrgan, J. Stegmeier, A.F.M. Moorwood

overview
Overview
  • Set-up
    • 32 channel package using CMOS cryo-opamps instead of ASIC’s
  • Test results with lc=2.5 mmHawaii2RG arrays
    • darkcurrent
    • QE
    • noise
    • Persistence
    • embedded reference pixels
    • Guide mode
introduction
Introduction
  • Single Hawaii-2RG used for 1 array operating in integral field spectrograph SPIFFI (lc=2.5 mm) 1 array in infrared spectrograph of X-shooter (1Kx2K needed, lc=2.5 mm) 3 arrays in K-band multiobject spectrograph KMOS (lc=2.5 mm) 1 array in planet finder
  • Mosaic of 2x2 2Kx2K Hawaii-2RG’s used for wide field imager Hawk-I (lc=2.5 mm)
  • ASICS not yet available, CMOS cryo-opamps used instead
  • 32 –channels better than 4 channels on ground because frame time < 1 s lower readout noise

better 1/f noise suppression with embedded reference pixels

32 channel package for hawaii 2rg
32 channel package for Hawaii-2RG
  • Mosaic for Hawk-I and KMOS ? In collaboration with GL Scientific
  • 32 channel package without ASICdeveloped for ESO
32 channel package for hawaii 2rg1
32 channel package for Hawaii-2RG

Cold finger

cryogenic

preamps

epoxy support structure

alignment screws

  • Tip tilt and focus adjustment by 3 alignment screws
  • Detector cooled by cold finger on the backside of the array
  • Use of cryogenic CMOS preamplifiers
32 channel package for hawaii 2rg2
32 channel package for Hawaii-2RG

cryogenic

preamps

Cold finger

  • Internal bus of array accessed directly by cryogenic CMOS amplifiers
  • Symmetric amplifier design for differential signal chain 32 video + 1 reference + 1 guide channel used in slow mode (100 KHz)
  • Bias and clock filtering at detector
thermal emission of cryogenic preamplifiers
Thermal emission of cryogenic preamplifiers

Heat-sinking of flex boards

  • Power dissipation of 68 CMOS cryo-opamps ~ 1W
  • Heater off detector on T=34.5K
  • Heater on detector off P=230 mW
  • proper thermal design and heat sinking of flex boards to instrument allows to heat sink77 % of power to instrument23 % of power to detector
thermal emission of cryogenic preamplifiers1
Thermal emission of cryogenic preamplifiers
  • Power dissipation of 68 CMOS cryo-opamps ~ 1W
  • Heater off detector on T=34.5K
  • Heater on detector off P=230 mW
  • proper thermal design and heat sinking of flex boards to instrument allows to heat sink77 % of power to instrument23 % of power to detector
  • Tdetetor = 90K

Tcryo-opamp=150K

  • Supply voltage of opamp

6V : Idark = 0.1 e/s/pixel 3V : Idark = 0.1 e/s/pixel

  • Cryo-opamps do not increase darkcurrent as demonstrated with SPIFFI set-up

2p

Measured temperature

2.7mm

2.6mm

2.5mm

f/10

kmos detector mount mechanical layout
KMOS detector mount mechanical layout

Micro-D 72 pin

ronnectors at

radiation shield

  • Detector enclosure and preamplifier box have to be galvanically separated from instrument
  • Power dissipation of 68 CMOS cryo-opamps ~ 1W
  • Heatload on detector P=230 mW
  • For HawkI mosaic four preamplifier boards instead of ASIC’s

Alignment

screws

Detector board &

cryo preamp

detector

Cooling braid

dark current versus temperature hgcdte lpe mbe
Dark current versus temperature HgCdTe LPE / MBE
  • LPElc=2.5mm■ Hawaii2 2Kx2K□ Hawaii1 1Kx1K
  • MBE lc=2.5 / 1.7 mm▲ Hawaii-2RG 2Kx2K lc=2.5mm ∆ PICNIC 256x256 lc=1.7mm
  • MBE at T<80K Idark < 0.01 e/s/pixel
  • at T=100K IMBE=ILPE /1660
  • Good lc=2.5mm MBE material can be used in liquid bath cryostats
dark current versus temperature hgcdte lpe mbe1

radiation background in SPIFFI

Dark current versus temperature HgCdTe LPE / MBE
  • LPElc=2.5mm■ Hawaii2 2Kx2K□ Hawaii1 1Kx1K
  • MBE lc=2.5 / 1.7 mm▲ Hawaii-2RG 2Kx2K lc=2.5mm ∆ PICNIC 256x256 lc=1.7mm
  • MBE at T<80K Idark < 0.01 e/s/pixel
  • at T=100K IMBE=ILPE /1660
  • Good lc=2.5mm MBE material can be used in liquid bath cryostats
t 60k
T=60K
  • Cut level-0.5/2 e/s/pix
  • Integration time 11 min
t 80k
T=80K
  • Cut level-0.5/2 e/s/pix
  • Integration time 11 min
detector operating temperature
Detector operating temperature
  • for a perfect science grade arrayIdark < 0.01 e/s at T < 80 K
  • for a real array cosmetic quality improvesif array cooled to T< 60 K
  • Required operating temperature depends on quality of science grade array
quantum efficiency 2 5 m m mbe hawaii 2rg
Quantum Efficiency 2.5 mm MBE Hawaii-2RG
  • Hawaii2 LPE QE drops with temperature
quantum efficiency 2 5 m m mbe hawaii 2rg lpe hawaii2
Quantum Efficiency 2.5 mm MBE Hawaii-2RG LPE Hawaii2
  • Hawaii2 LPE QE drops with temperature
  • Hawaii-2RG MBE QE does not dependent on temperature
  • Science grade QE K-band: 0.84 H-band: 0.78 J-band: 0.71
quantum efficiency versus wavelength
Quantum efficiency versus wavelength
  • Smooth curve to obtain final result
  • Engineering grade using shot noise:K: 1.05H: 0.81J: 0.65

engineering

grade

conversion gain by capacity comparison method
Conversion gain by capacity comparison method
  • Charge for resetting node capacity is provided by bias voltage Vreset
conversion gain by capacity comparison method1
Conversion gain by capacity comparison method
  • add external relais and large external capacity Cext
  • charge for resetting node capacity is provided by Cext
  • eventually, after reading many frames, voltage across Cext will drop due to charge loss caused by resetting node capacity C0 ( nframesx2Kx2K resets)
quantum efficiency versus wavelength1
Quantum efficiency versus wavelength
  • Smooth curve to obtain final result
  • Engineering grade using shot noise:K: 1.05H: 0.81J: 0.65

engineering

grade

quantum efficiency versus wavelength2
Quantum efficiency versus wavelength
  • Smooth curve to obtain final result
  • Engineering grade using capacity comparison:K: 0.83H: 0.64J: 0.51

engineering

grade

quantum efficiency versus wavelength3
Quantum efficiency versus wavelength
  • Smooth curve to obtain final result
  • Engineering grade:K: 0.83H: 0.64J: 0.51

engineering

grade

quantum efficiency versus wavelength4
Quantum efficiency versus wavelength
  • Smooth curve to obtain final result
  • Engineering grade:K: 0.83H: 0.64J: 0.48
  • Science gradeK: 0.84H: 0.78J: 0.71Z: 0.66

science

grade

engineering

grade

noise map of hawaii 2rg l c 2 5 m m mbe array
Noise map of Hawaii-2RG lc=2.5 mm MBE array
  • Noise map for Hawaii-2RG
  • 13.4 erms on active pixels
  • 6.3 erms on reference pixels
  • Dominant noise source is IR pixel, not mux or acquisition chain
  • Clean set-up

4 columns of reference pixelson each side of the array

readout noise versus number of nondestructive readouts
Readout Noise versus number of nondestructive readouts

Fowler sampling:

number of readouts n

proportional to integration time: 825 ms/readout

for 256 Fowler pairs 2.2 erms on IR pixels

1.3 erms on reference pixelsscales to subelectron noise for Si-pin diodes ( HyVisi)

shielding multiplexer glowvery efficient: large number of nondestructive readouts possible with 32 channels

readout noise 256 fowler pairs 2 5 m m mbe hawaii 2rg
Readout Noise 256 Fowler pairs2.5 mm MBE Hawaii-2RG
  • 1.3 erms on reference pixels
  • 2.3 erms on active pixels
glow centers
Glow centers
  • For large number of nondestructive readouts engineering grade arrays show glow centers
  • Fixed integration time 900s
  • Vary number of nondestructive readouts
intensity of glow centers
Intensity of glow centers
  • Integration time 900 s
  • Glow proportional to number of nondestructive readouts
  • 27 pixels from center glow intensity is 61 e/frame
glow centers1
Glow centers
  • several isolated glow centers for large number of readouts on engineering array
  • No glow center on science array
  • Diffraction like ring structure
  • Selection criterium for science arrays
  • Hole in metal shield of MUX ?
persistence
Persistence
  • switch from LPE to MBE does not eliminate persistence
  • latent image can be seen for many hours
  • persistence on all arrays tested
persistence1
Persistence
  • depends on fluence not on flux
  • N<Nsaturation=105eno persistence
  • switch from LPE to MBE does not eliminate persistence
  • latent image can be seen for many hours
  • Threshold of persitence because of traps close to the pn junction ?

105e

low frequency noise suppression with embedded reference pixels
low frequency noise suppression with embedded reference pixels
  • Integration time 1.01 s
  • high frequency stripes in direction of fast shift register are 50 Hz pickup
  • Noise 45 erms
  • For each row subtract average of 8 embedded reference pixels on right and left edge of the array
  • With 32 channels reference pixels are read twice every 420 ms
  • Noise 24 erms
  • Linear interpolation of reference for each pixel using reference pixels of row and reference of subsequent row
hawaii2gr in integral field spectrograph spiffi
Hawaii2GR in integral field spectrograph SPIFFI

detector cooling braid

  • Liquid bath cryostatTdetector = 90 K
  • lc=2.5 mm MBE Hawaii-2RG
  • Heat sinking of cables

Heat

sink

for

clock

video

bias

cables

spiffi

dec

wavelength

Pseudo Longslit 30 cm

ra

Small Slicer 1 cm

SPIFFI

SPIFFI: SPectrometer for Integral Faint Field Imaging (MPE)

  • Fully cryogenic spectrometer for the near infrared wavelength range from 1.0 – 2.5 µm
  • Integral field unit with 32 x 32 pixels

Large Slicer

hawaii2rg in integral field spectrograph spiffi
Hawaii2RG in integral field spectrograph SPIFFI
  • K-band spectrum of Ne lamp
  • Slitlets staggered because of image slicer
  • Pixel scale 0.1 arcsec
  • FWHM = 1.4 pixels
  • Spectral resolution 6300
hawaii2rg for hawk i
Hawaii2RG for Hawk-I
  • 1-2.5µm
  • All mirror optics
  • 4kx4k mosaic detector
  • 0.1” pixels 7.5x7.5’ field
  • Designed for possible use with adaptive secondary +laser guide stars
guide mode for tip tilt correction with lgs ao sytem
Guide mode for tip-tilt correction with LGS-AO sytem
  • Laser guide star AO system still need natural guide star for tip-tilt correction
  • use guide mode of Hawaii-2RG arraysfor tip-tilt correction with NGS
timing of guide window readout
Timing of guide window readout
  • Fowler or follow up-the-ramp sampling for science frame
  • Interleave guide window readout with full science frame readout
  • Guide window readout is nondestructive without reset: always subtract previous frame from new frame
  • only one read needed per double correlated image
  • Gain of 2 in bandwidth in comparison to read-reset read
guide window read reset read
Guide window read-reset-read
  • Window 16x16
  • Star mag 9.5
  • 256 windows perfull frame
guide window read read read
Guide window read-read-read
  • Window 16x16
  • Star mag 14
  • 64 windows per full frame
  • Frame rate 68 Hz
  • Guide window is not lost for science frame
irace
IRACE

136 channel

IRACE system

similar system

already

operational

for CRIRES

irace for hawaii2rg 32 channel and guide window

2 ADC boards

for 32 channels

of science frame

ADC board

for guide

window

IRACE for Hawaii2RG 32-channel and guide window

Add

ADC board and

2nd gigalink

for guide

window

irace for hawaii2rg 32 channel and guide window1

Gigalink

for 32 video

channels of

science frame

Gigalink

for guide

window

IRACE for Hawaii2RG 32-channel and guide window

Additional

ADC board and

2nd gigalink

for guide

window

IRACE is

flexible

architecture

covering all

Applications

Port flexibility to

NGC

irace for 2x2 mosaic of hawaii2rg s and guide mode
IRACE for 2x2 mosaic of Hawaii2RG’s and guide mode
  • 136 channel system16 bit 500 kHz

4x32 video channels4x1 reference channels4x1 guide window channels

  • Gigabit fiberlink
  • cryo-opamps instead of ASIC
  • Linux pc as number cruncherwith home-made pci-bus gigalink interface
conclusions
Conclusions
  • 32 channel setup with cryo-opamps operational at telescope
  • GL-scientific Mosaic package with128 channels for Hawk-I
  • QE high over the entire spectral range (K: 0.84, Z: 0.66) with correct PTF
  • With MBE dark current < 0.01 e/s at T< 80 K operation in LN2 bath cryostat possible, cosmetics improves at lower temperatures
  • Reference pixels eliminate drift and reduce pick-up: robust system
  • Readout noise double correlated sampling 13.4 erms on IR pixels 6.3 erms on reference pixels
  • Glow shielding on Hawaii-2RG efficientReadout noise with 256 Fowler pairs

2.2 erms on IR pixels 1.3 erms on reference pixels

  • Guide mode does not disturb science frame
  • Routine operation of Hawaii2RG in integral field spectrometer SPIFFI at the VLT with spectacular results on galactic center
readout noise versus number of nondestructive readouts1
Readout Noise versus number of nondestructive readouts

Fowler sampling:

number of readouts n

proportional to integration time: 825 ms/readout

for 256 Fowler pairs 3 erms on IR pixels

1.8 erms on reference pixelsscales to subelectron noise for Si-pin diodes ( HyVisi)

shielding multiplexer glowvery efficient: large number of nondestructive readouts possible with 32 channels

STScI

quantum efficiency versus wavelength5
Quantum efficiency versus wavelength
  • Smooth curve to obtain final result
  • Engineering grade using shot noise:K: 1.05H: 0.81J: 0.65

engineering

grade

guide window read read read1
Guide window read-read-read
  • Window 16x16
  • Star mag 14
  • 256 windows per full frame
  • Frame rate 143 Hz
  • Guide window is not lost for science frame
comparison of cosmetic quality 40k 80 k
Comparison of cosmetic quality 40K / 80 K

T=40 K

T=80 K

Cut levels -250 e /200 e , DIT 900 sec

integral field spectroscopy
Integral field spectroscopy
  • optically slice image
  • align slices on slit of spectrometer
  • take spectrum for each pixel in 2dimensional image
ad