Suprime-Cam Upgrade Plan

Notice to prospective Suprime-Cam users

We are planning a major upgrade work of Suprime-Cam in 2008. This work will require about 6 weeks and probably be carried out in late S08A, during which Suprime-Cam will temporarily be unavailable.

The upgraded Suprime-Cam will be offered to open use programs after we fully evaluate the new system performance and confirm that there is no significant degradation in the performance.

Prospective users of Suprime-Cam are basically asked to prepare for their proposals by assuming the current system parameters such as the system throughput, read noise, and saturation level. Subaru Imaging Exposure Time Calculator is based on the current system parameters.

However, submission of proposals assuming characteristics of the upgraded system is also acceptable on a risk-shared basis only. This means that if the upgraded system does not become operational by the beginning of any observing run, observations allocated in that run which assume the upgraded system will have to use the current system instead of the new one. Those who would like to propose a program assuming the upgraded system should contact Support Astronomer of Suprime-Cam prior to preparation of their proposals so that they could obtain appropriate parameters to be used in their proposals.

Major changes in the upgrade

In the forthcoming upgrade work, the following changes will be made which are relevant to observations and data reduction.

Fully-depleted-type CCDs
Current 10 CCDs (MIT/LL) will be replaced with fully-depleted-type 2Kx4K CCDs developed in collaboration with Hamamatsu Photonics K.K. With the new CCDs, the system throughput in red wavelengths will be enhanced (the quantum efficiency is about 40% at 1 micron) without a significant decrease in blue wavelengths. The pixel scale (and the field of view, of course) will be kept the same as in the current system.
A new front-end electronics for the CCD operation
A new front-end electronics (Mfront2) will be installed in replacement of the current M-Front system. Mfront2 is dedicated for the new CCDs with 4 readout channels per chip and brings us faster readout time. The readout time for observations is targeted 20 sec per shot, but will be determined by examining the read noise level.
Data format and data reduction
Due to employment of the new CCDs together with the new electronics, data format acquired with the new system will be slightly changed from the current configuration. This change will include gain, saturation level, and configuration of overscan regions etc. All the information necessary for the data reduction including measured new system parameters will be provided to users when the upgraded Suprime-Cam is offered to the open use programs.