Improved performance with NTD temperature controllers


The image above shows the improved noise performance we see with the new NTD (neutron transmutation doped) devices which we are just now using to temperature control the focal plane arrays (there is one  NTD device per focal plane). The data show sequential noise measurements made with the instrument shutter closed (i.e. in the dark) for 6 of the arrays in SCUBA-2. Sequences spanning 1 to 120 show the measured noise without the NTD control loop switched on, and sequences 121 to 250 with it switched on (ignore the large spike around sequence 130 which is likely due to “settling time issues”)

Use of the NTD control loop to stabilise the temperature of the focal planes has a clearly significant and beneficial effect on the stability of all of the arrays over the course of the 6 hours that these test data were acquired.  Similar tests were repeated on two subsequent nights and showed the same benefit from having the NTD temperature control of the focal planes switched on.

Advertisements

One Response to Improved performance with NTD temperature controllers

  1. The objective, according to GISS scientists, is to provide an estimate of temperature change that could be compared with predictions of global climate change in response to atmospheric carbon dioxide, aerosols, and changes in solar activity.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: