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GREAT. GREAT: G erman RE ceiver for A stronomy at T erahertz frequencies. Lab-picture of GREAT equipped with theL#1 and L#2 channel. PI-Instrument funded and developed by MPIfR (2.7THz channel) R. Güsten (PI) S. Heyminck (system engineer) B. KIein (FFT spectrometer)
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GREAT GREAT: German REceiver for Astronomy at Terahertz frequencies Lab-picture of GREAT equipped with theL#1 and L#2 channel • PI-Instrument funded and developed by • MPIfR (2.7THz channel) • R. Güsten (PI) • S. Heyminck (system engineer) • B. KIein (FFT spectrometer) • MPIfR Engineers (electronics, LO-mechanics) • KOSMA (1.4/1.9THz channels) • J. Stutzki (Co-PI) • U.U. Graf et al. (1.4 &1.9THz LO, Optics) • K. Jacobs et al. (mixers @1.9THz & 2.7THz) • R. Schieder et al. (array-AOS) • DLR-Berlin (4.7THz channel) • H-W Hübers et al. (IF, cold-Load, …) • MPS • P. Hartogh et al. (CO-PI; CTS)
Early-Science Configurations GREAT flight configurations: • baseline: simultaneous observations with 2 low-frequency channels • goal: fly mid-frequency channel at the earliest possible • upgrade: operate 4.7 THz channel (not in short and basic science) Short science configuration: • baseline configuration (2 low-frequency channels) Basic science configuration: • goal configurations (combinations of the mid and low-frequency channels)
GREAT in L-L configuration Cryostats Oscilloscope Cold-load LO-synthesizer #1 Optics control Mixer-BIAS #1 & #2 Instrument computer SI mounting flange Power-supply SOFIA PI-rack LO-synthesizer #2 Monitor drawler 1.9 THz Solid-state LO 1.4 THz Solid-state LO Power distributor Ethernet-HUB Obs-computer IF-Power-supply FFTS IF Pre-processor CTS #1 and #2 IF LO-supply AOS-system IF-processor Chopper control Picture taken by DLR
Stoplight-chart GREAT L-L configuration passed its PSR in Dec. 2008 and is ready for shipment SOFIA schedule is still slipping fast GREAT is in sleep mode now: only technology development for THz LO-sources and for mixers no further testing / development activities on GREAT • Comments: • M-Band Solid-State-LO technical risk (not short science) SOFIA schedule
M-Band channel developments optics and cryostat are ready cryostat is full wired, cold-optics assembly is ready diplexer setup(Martin Puplett) 77K-stage LO-injection(via wire-grid) 4K-stage optical bench cold-optics (incl. mixer-mount)
Photonics LO developments photonics LO is now the baseline LO-system solid-state LO is backup now(but still under development) approx. 150nW at 2.5 THz measured at first shot(including uncoated window and silicon lens, not optimized) first 2.5 THz HEB pump-tests are scheduled for the next months LO was successfully tested at APEX in summer 2009 150nW output power of the LO-system optics amplifier Fiber-connection Design study:3D-CAD drawing of the laser-amplifier setup of the SOFIA photonics LO
GREAT H-Band • channel will be ready in summer 2010 • using the original laser-lo system • upgrade to QCL-LO is under development at the DLR-PF • good chance to have it in hand after the SOFIA down-time (for LOC) Future Plans for the H-Band channel: • upgrade to 4 pixels • needs the QCL-LO • can most likely make use of the GREAT standard cryostat • no big airworthiness overheads • timeline: operational readiness in 2014 should be possible (maybe for FOC) • possible upgrade to 7 pixels • needs redesign of the cryostat • new airworthiness procedure required • timeline: unclear First we need to gain confidence in the SOFIA project schedule
6 years of schedule history GREAT schedule from Sept. 2003 SOFIA schedule from Nov. 2009 This requires shipping GREAT in September 2010
Schedule towards first (f)light GREAT needs 24 weeks prior to short science #2 for: re-testing the first flight configuration(as accepted in PSR Dec. 2008) incl. testing of new HEB mixers and amplifiers shipment post-shipment test in Palmdale integration test aboard SOFIA (incl. EMI-test)