First Science Raft Tower Module Completed!

First Science Raft Tower Module Completed!

December 9, 2016 - The Science Raft team, located primarily at Brookhaven National Laboratory (BNL), has constructed the very first Science Raft Tower Module populated with a full array of 9 CCDs and 3 Raft Electronics Boards (REBs).  The Raft is an Engineering Test Unit (ETU1), which was assembled for design and construction validation purposes and will be used to support commissioning efforts at Test Stand 8 where a full suite of electro-optical tests will be performed at the Raft level.  The Raft Sensor Assembly (RSA) for this ETU was already leveraged to commission Test Stand 5, where warm and cold RSA metrology is performed at temperatures as low as -100oC.  An end-to-end connectivity test was performed successfully on ETU1 using control and monitoring software developed by the project's CCS group. This test verified good connectivity between all 9 CCDs and each of the REB4 boards, with image data transferred to the prototype Data Acquisition System. These were all very important achievements for the Science Raft team as well as many other Camera team members that supported this effort.  When asked for comments about meeting this important milestone, Bill Wahl expressed much appreciation for the vital support that was provided by other institutions including SLAC, Harvard, UPenn and IN2P3.  Bill continued to say that this achievement would not have been possible if it were not for the teamwork approach and collaborative spirit that was adopted early on. 

In addition to constructing ETU1, the team recently constructed another RSA for a second Engineering Test Unit (ETU2), which will be completed by the end of January.  Unlike ETU1, this ETU will include REBs that represent the production configuration (REB5), which is currently being tested at BNL and SLAC with very good results. The recent REB successes are allowing the team to proceed to full board production starting later this month, with assembled boards becoming available for RTM construction in late March. The team expects to begin construction of the very first production RTM later this month starting with the RSA now that materials are available including the CCDs.  The completion of RTM1 is expected in late March, ahead of the Level 2 DOE milestone, which has a completion date in mid-April.  The team is confident they will meet each of these important milestones and they look forward to commencing Raft production in the New Year. 

Photons in – bits out

  • Autonomous, fully testable 144-Mpixel imager
  • 9 CCDs with low noise analog signal processing electronics
  • 12.7 x 12.7 x 42cm3
  • 50W power dissipation

ETU under test in BNL cleanroom


Financial support for Rubin Observatory comes from the National Science Foundation (NSF) through Cooperative Support Agreement No. 1202910, the Department of Energy (DOE) Office of Science under Contract No. DE-AC02-76SF00515, and private funding raised by the LSST Corporation. The NSF-funded Rubin Observatory Project Office for construction was established as an operating center under management of the Association of Universities for Research in Astronomy (AURA).  The DOE-funded effort to build the the Rubin Observatory LSST Camera (LSSTCam) is managed by the SLAC National Accelerator Laboratory (SLAC).
The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 to promote the progress of science. NSF supports basic research and people to create knowledge that transforms the future.
NSF and DOE will continue to support Rubin Observatory in its Operations phase. They will also provide support for scientific research with LSST data.   

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