Workshop Goal
Welcome to the workshop
Background
Operation approved until 2011 March
Need to prepare budget proposal in next January
for continuation of observations after 2011 March
Discussion of excellence of Phase 3 data
Proposal for new observations

Phase 3 observations(by courtesy of F. Usui)AOTs in phase 3
by courtesy of F. Usui

Current Status of IRC
When the Phase 3 will be terminated?
AKARI/IRC team and
Takehiko WADA (ISAS/JAXA)
wada@ir.isas.jaxa.jp

the IRC Warm mission
2007/08/26 08:33 UTC exhaustion of super fluid HeTemperature of SIA goes up to 40K
MIR-S/L channel is not usable
NIRchannel is still operational

Imaging observations in 2, 3, and 4um band
Spectroscopy (R=30/100) in 2-5um
The only space spectroscopy until JWST

3 years is approved for the warm mission. (2008, 2009, 2010)2008/06/01- Science observation for P3-I
-2009/10/14 Phase-3-I ends
2009/10/15- Phase-3-II starts

The status of IRC Warm mission
most of IRC function is normal
no problem on FW operation
PSF/AOCS is stable
read noise is stable

drift of detector temperature changesdark/hot pixel
photo responseStabilization trends in Phase 3
Number of NIR frames in a pointed obs. (AOT:IRCZ3)

Number of NIR frames in a pointed observation

2015

10

Stabilization threshold adjust
IRU-A S-gyro OFF
Stabilization threshold adjust
No normal obs.
because of Safe hold5

IRU-A adjustment

0
08/03

08/05

08/07

08/09

08/11

09/01

09/03

09/05

09/07

09/09

09/11

Date [YY/MM])No significant problem in attitude stabilization found after Safe-hold at 2008/07.

Detector Temperature trends in Phase 3
temperature of detectors and telescope (Primary Mirror)
45

40

NIR
MIR-S
MIR-L
PM

temperature[K]

3530

25

20

15

10

5

09/01

10/01

11/01

12/01

01/01
UCT[m/d]

02/01

03/01

04/01

05/01

06/01

Detector Temperature trends in Phase 3
temperature of detectors and telescope (Primary Mirror)
47
46

NIR
MIR-S
MIR-L
PM

45

temperature[K]

44
43
42
41
40
39
38
07/10

08/01

08/04

08/07

08/10

09/01

09/04

09/07

UTC[y/m]seasonal bump at winter and summer solsticeglobal rising trend probably due to degradation of the cooler
the trend has eventually stopped recently...
prediction of detector temperature trend is now a mystery.

09/10

temperature dependence of dark current and noise
dark/noise of NIR detector (Vbias=400mV)
NIR dark
NIR noise
NIR dark 0907
NIR noise 0907

100

read noise(e), dark (e/s)

dark reaches 10% of saturation level in long exp. frame (44s)

1010.1

38

39

40

41

42

43
44
45
temperature (K)

4647

48

4950

dark shows strong correlation with detector temperature
no permanent degradation was found after the peak at 2009/07

noise shows weak correlation with detector temperature probably due to dark shotnoisetemperature dependence of number of hot pixels
Number of hot/noisy pixel in NIR detector (Vbias=400mV)
NIR num of noisy pixel(noise>100e)
NIR num of hot pixel(dark> 50 e/s)
NIR num of noisy pixel 0907 (noise>100e)
NIR num of hot pixel 0907 (dark> 50 e/s)

number of hot/noisy pixels

10% of toal pixels

10000

1000

38

39

40

41

42

43
44
45
temperature (K)

46

47

48

49

50

number of dark/hot pixel shows strong correlation with detector temperature
no permanent degradation was found after the peak at 2009/07

Summary
AKARI/IRC has been finished its mission in Phase 1 and 2
Three year mission is approved for Phase 3 (2008-2010)
Imaging observation in 2, 3, 4um
low resolution spectroscopy in 2-5um
most of IRC function is normal
drift of detector temperature causes change in
dark/hot pixel
dark will reach 10% of saturation level at 47K

photo response
20% drift are seen between 40K and 47K
correction for response as a function of temperature are now considered.

prediction of detector temperature trend is difficult.
No one knows when the Phase 3 ends......