Noise Modeling using Photon Transfer Curves

Thomas Rust MOSES Group Meeting

October 31, 2012

=G2!2 !P"i +G

2!F +" READ

2

= G !I "i # ped( )+G2F( )! +"

READ

2

!i

2=!

SHOT

2+!

FANO

2+!

READ

2

!I "i =G!!P"i + ped

!!!E,!

E<!Charge Collection Issues:

! i

2= G !I "i # ped( )+G2

F( )"E+!

READ

2

!I "i =G!!P"i + ped

Need to measure ! READ

2, ped,G,"E

!E =" EUV

2 !" READ

2

G "I #BOX ! ped( )+G2F

! BOX

2= G !I "BOX # ped( )+G2

F( )"E+!

READ

2+!

FIXED

2

!I "BOX =G!!P"BOX + ped

! dI ,BOX

2= G !I "BOX # ped( )+G2

F( )"E+!

READ

2

dI !I2" I

1

2

[e-/phot]

G =! RED

2 !! READ

2

"I # ! ped

! RED

2=G !I " # ped( )+!

READ

2

! > 400nm :

measured from bias images (dark current at room temp)

! READ

2, ped

[DN/e-]

G is temperature dependent.

Procedure

•  Expose CCD’s to pulsed 635 nm LED •  Vary exposure level from dark to A/D

saturation •  Two images at each exposure level •  Difference same exposure images •  Compute for many locations on

CCD •  Plot on log-log scale

!dI ,BOX

2, !I "

BOX

Results

1/G [e-/DN]

RMS Read Noise [e-]

Min Full Well

[ke-]

m = -1

6.23

13.00

95.7

m = 0

6.40

13.22

99.9

m = +1

6.25

14.08

98.1

TO DO

•  Cooled (vacuum) red light photon transfer •  Measure effective quantum yield in EUV

noise model •  PTC – Flatfield Connection

Thanks

Pat Lokken Hans Jake Plovanic Charles Norm Bo Larry

References

•  Janesick, J. (2001). Scientific Charge-Coupled Devices. SPIE Press.

•  Janesick, J. (2007). SPIE Press. DN ! !.