Table 1 Operation of IR2 cryo-cooler

1

12/10/2015

Start the cooler

10.61

15

12/10

Increase the driving voltage

13.25

30

16 h after start-up

2

12/11

First 2.02-μm image

13.25

30

3

01/20/2016

Unexpected shutdown

13.25

30

Before the end of penumbra

4

01/25

Restart the cooler

10.61

15

01/26

Increase the driving voltage

13.25

30

5

01/28

Unexpected shutdown

16.08

N/A

Large fluctuation in current

6

02/12

No cooling when restarted

10.61

15

03/09

External heater to warm up

–

–

7

03/10

Restart the cooler

10.61

15

Successfully restarted

03/11

Increase the driving voltage

13.25

30

8

03/15

Planned shutdown

–

–

To remove contaminants

9

03/15–03/21

External heater to warm up

–

–

10

03/22

Restart the cooler

10.61

15

Successfully restarted

03/22

Increase the driving voltage

15.25

40

Via 13.25 V (30 W)

11

04/18–04/22

Testing small-step increases

Small UPs and DOWNs

04/28

Increase the driving voltage

15.92

Via 15.59 V

04/29

Increase the driving voltage

16.08

12

04/30

Increase the driving voltage

16.25

46

This became the “nominal”

13

05/27

Enter the superior conj. mode

13.25

30

No obs. during superior conj.

14

06/16

Recover from superior conj. mode

13.60

06/17

Recover from superior conj. mode

14.26

Via 13.93 V

06/20

Recover from superior conj. mode

14.92

Via 14.59 V

06/21

Recover from superior conj. mode

15.25

40

06/23

Recover from superior conj. mode

15.59

06/24

Recover from superior conj. mode

15.92

06/27

Recover from superior conj. mode

16.08

15

06/28

Recover from superior conj. mode

16.25

46

16

11/07

Decrease the driving voltage

15.25

Attempt to improve stability