1. Proposed US Contribution to the Wide Field Imager PSU MIT JHU

2. History PSU, MIT, and SAO approached about four years ago to contribute to IXO WFI instrument. Proposed US contribution to IXO WFI was in the ICU hardware and software. – This provided a clean interface between US and European hardware. – Drew upon decades of combined US experience with X-ray imaging instruments Murray/SAO-JHU: Einstein HRI, ROSAT HRI, Chandra HRC Bautz/MIT: ASCA SIS, Chandra ACIS, Suzaku XIS, Astro-H SXI Burrows/PSU: Chandra ACIS, Swift XRT

3. US Response to L2 Paul Hertz (director of NASA’s Astrophysics Division) has expressed interest in contributing to an L2 mission at a level of up to $150M. The US X-Ray Science Interest Group (XRSIG) prepared a list of possible US contributions to ESA’s L2 mission for Paul’s consideration. This list included a US contribution to the ATHENA WFI instrument along the lines of the IXO contribution. ESA Call for L2 Mission Concept proposals clearly permits US contributions to Instrument Teams

4. The current WFI architecture is similar to the IXO WFI architecture as of summer 2010 High speed fiber optic data link proposed 2048 x 2816 pixels total, read out every 2 μs (?) => 1 Gpix/s – 1.5 Gpix/s ?

5. Proposed US contribution to WFI US contribution US contribution: ICU Provides clean interface between US and European responsibilities Capitalizes on initial development of high-speed event recognition Propose fiber optic data transfer bus to WFI Movable Instrument Platform ?

6. Instrument Control Unit (ICU) Concept Based on IXO WFI / June 2010

7. Fiber Optic interface Assumed 8 optical fibers (for IXO/WFI) – Mass < 500 g – Power < 3W – Cost ~ $70K – Double numbers for redundancy Requires use of Xilinx FPGAs to interface to optical fiber transceivers – Xilinx Virtex-5QV FPGAs are rad-hard, 1 Mrad dose – Virtex-5 are fast enough, >3 GHz multi-gigabit serial

8. IXO WFI Instrument Control Unit Block Diagram June 2010 D. Burrows Spacecraft Com GSE connection Power Science Data Housekeeping Data Slow Control Bus Housekeeping / Relays / Mechanisms Instrument Processor Board (128K PROM, 512K EEPROM, 4MB SRAM, 512MB SDRAM) Frame Builder 1 Custom FPGA / SRAM Power Supply Board Spacecraft Comm / Mem Board (512 MB Flash) S/C Power Spacewire ICU Block Diagram Frame Builder 2 Custom FPGA / SRAM To Filter Wheel Stepper Motor To APS Htr +3.3V Digital Power To HPP (x2) +1.7V ASIC Power ASIC Substrate Power Fiber Optic Cables from HPPs 1 PPS Slow Control (Spacewire)

9. ICU Concept (8 slot version) 29.5 cm 2.5 mm 23.2 cm

10. ICU Concept 2.5mm Al chassis for shielding (5 kg) 3U/6U box, 6 slot backplane (488 g) – Slot 0: LVPS (500 g, 11.25 W @ 70%) – Slot 1: 3U System Slot, Instrument Processor Board (450 g, 3.55 W) Instrument control, telemetry formatting – Slot 2: 6U Comm/Memory Board (880 g, 3.55 W) – Slot 3: 6U Frame Builder Board 1 (880 g, 6.25 W) – Slot 4: 6U Frame Builder Board 2 (880 g, 6.25 W) – Slot 5: 6U HK / Relay / Mechanism Board (880 g, 6.50 W) – Slot 6: spare Total mass: ~ 10.0 kg Total power: 37.4 W

11. ICU Concept Mass (IXO PDD allocation is 26.5 kg, w/ redundancy): – Total mass: 10.0 kg (CBE) – Total redundant mass: 25.9 kg (CBE+30%) Power: – ICU Power: 37.4 W (CBE) – Total + 20%: 44.9 W (CBE + 20%)

12. Summary PSU, MIT, and JHU are excited to have a chance to contribute to this mission! Interested in ICU: – Power, mechanism control – Frame builder and telemetry formatting – Hardware and software – Joint development by PSU, MIT, JHU Note that we also have experience in large thin filters for Chandra (HRC and ACIS)

13. Backup Slides Based on IXO WFI / June 2010

14. Proposed US Contribution to WFI Based on IXO WFI instrument teaming arrangements Proposed US contribution: frame builder and event processing software PSU: provide high-speed digital framework, high-speed fiber interface to FEE JHU: frame builder (event recognition) MIT: flight software (event processing) Builds on decades of combined experience in X-ray imaging instruments, including Murray/SAO-JHU: Einstein HRI, ROSAT HRI, Chandra HRC Bautz/MIT: ASCA SIS, Chandra ACIS, Suzaku XIS, Burrows/PSU: Chandra ACIS, Swift XRT

15. Fiber Optic interface to ICU www.spacephotonics.com

16. Fiber Optic interface to ICU www.spacephotonics.com Design flexibility, good radiation tolerance, high speed, low power

17. FEE ADC FPGA CAMERA Flex cable Instrument Control CPU Frame Builder S/C I/F Slow Control/Config Power Conditioning H/K Image Controller / APS Sequencer Controller Power Heater Power/Cont rol ASIC Power Sensor Power Processor Power JHU PSU UL MIT mechanism controls Software WFI baseline ICU

18. WFI ICU 1)CPU = Brain + Slow control 2)PSB: low voltage power supplies 3)S/C Interface (SpaceWire?) 4)Camera Interface (serial optical + SpaceWire?) 5)HK: all HK from outside the ICU will be digitized locally and provided to ICU on the slow control bus 6)Heater power / mechanisms 1)Detector temperature control 2)Filter stepper motor (if needed) 3)any other heaters or mechanisms 7)Frame Builder (JHU) 1)Frame buffer 2)Event recognition and formatter 8)System Software (PSU/SwRI) 1)O/S, drivers, S/C interface, heater control,... 9)Science Software (MIT/JHU) + Fully Redundant B-side 1)CPU = Brain + Slow control 2)PSB: low voltage power supplies 3)S/C Interface (SpaceWire?) 4)Camera Interface (serial optical + SpaceWire?) 5)HK: all HK from outside the ICU will be digitized locally and provided to ICU on the slow control bus 6)Heater power / mechanisms 1)Detector temperature control 2)Filter stepper motor (if needed) 3)any other heaters or mechanisms 7)Frame Builder (JHU) 1)Frame buffer 2)Event recognition and formatter 8)System Software (PSU/SwRI) 1)O/S, drivers, S/C interface, heater control,... 9)Science Software (MIT/JHU) + Fully Redundant B-side

19. Issues/Questions Power Conditioning in ICU box: – Controller power (3.3V for Brain, HK, slow control): Commandable (by ICU) – control via solid-state switches to 2 HPPs – Processor power (Frame Builder) – Operating power for filter wheel: Commandable Stepper controller in ICU, directly power filter wheel stepper motor – Heater power for APS heaters: Adjustable in ICU – analog power need to sense temperature, control heater power to maintain constant temperature to within 0.1K – ASIC power Analog supply voltages (~ 3-5V for AFE/CFE ASICS): Commandable (by ICU) – +/- supply for ASICs (1.7V), 3.3V for switcher, substrate voltage for switcher ASIC – control via solid-state switches, with separate switches for 2 HPPs

20. Issues/Questions Housekeeping: – “All voltage channels can be read back via slow control for housekeeping purposes” Does ICU get analog or digital HK from remote boxes? Yes – “ All currents can be monitored by housekeeping” Does this include currents generated in remote boxes? Yes Heaters: – APS temperature control – we supply controlled analog voltage – must keep temperature variation < 0.1 K

21. Issues/Questions Slow control: – resides in ICU – is it a digital communications link to smart remote ports? Yes “The slow control configures the entire system via a relatively slow serial link. It also commands switching of power supplies for the respective operating modes.”