Suprime-Cam Upgrade Plan

Notice to prospective Suprime-Cam users

We are conducting a major upgrade work of Suprime-Cam inlcuding CCD replacement in 2008.

The upgraded Suprime-Cam is under evaluation and will be offered to a nomal observing mode from the S09B only when the system is fully tested. The performance of the new system will be provided in the call for proposal for S09B.

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.

For S09A, 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.
In addition, even if the upgraded system becomes operational by the observing runs, the data obtained with the new system is still under evaluation. The system may also have to be restored back to the original one with MIT CCDs even during the semester if any problem is found.

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.
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.
We ask open-use users to perform their feasibility studies for observations using the new CCDs based on the below values:
Quantum Efficienty
```
band          U       B       V       Rc      i      z'     9573A    ZR
MIT-CCD     0.247   0.617   0.750   0.836   0.865   0.551   0.410   0.199
HPK-FDCCD   0.287   0.559   0.849   0.932   0.913   0.758   0.673   0.386

(*) The above values are derived from Miyazaki et al. 2002 PASJ 54, 833 (MIT-CCD) 
   and Kamata et al.  2008 SPIE in press (HPK-FDCCD).
```
Overhead time for readout
The overall overhead time for a readout cycle including readout, erase, wipe operations for the FDCCDs is approximately same as for the MIT CCDs.
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.
Information necessary for the data reduction including measured new system parameters will be provided to users after the upgraded Suprime-Cam is fully evaluated.