SITR April 2009; Page 1

MPIfRKOSMAMPSDLR-Berlin

S. Heyminck, MPIfR

GREAT

GREAT: German REceiver for Astronomy at Terahertz frequencies

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, …)

MPSP. Hartogh et al. (CO-PI; CTS)

Lab-picture of GREAT equipped with theL#1 and

L#2 channel

SITR April 2009; Page 2

MPIfRKOSMAMPSDLR-Berlin

S. Heyminck, MPIfR

Early-Science Configurations

GREAT flight configurations: baseline: simultaneous observations with 2 low-frequency channels goal: fly mid-frequency channel at the earliest possible (altitude) 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)

request pending for schedule adjustment with envelope expansion prior to GREAT SS flights

Channel Frequencies [THz] Astronomical lines of interest low-frequency #1 1.25 – 1.50 [NII], CO(12-11), (13)CO(13-12), HCN(17-16), H2D

+

low-frequency #2 1.82 – 1.92 [CII], CO(16-15) mid-frequency 2.4 – 2.7 HD, OH(23/2), CO(22-21), (13)CO(23-22) high-frequency 4.7 [OI]

SITR April 2009; Page 3

MPIfRKOSMAMPSDLR-Berlin

S. Heyminck, MPIfR

Stoplight-chart

ongoing project schedule delays pose incalculable risk on integrity of GREAT project

funding at risk, more than everloosing support of interested G communitiesscience return of “investment” unpredictable for consortiumplanning of instrument developments vs. other projects is impossiblehow to restore confidence in stability of project schedule ?

not communicated welldelay of almost one year came by surprise

(old schedule was confirmed at PSR in Dec. 2008)

Item Technical ScheduleBudget RemarkStructure Finally assembledCryostat 6 units Delivered, hold-time >24hOptics works fine at 1.9THzDetectors (HEBs) 1.9THz ready, development ongoingControl-Electronics final integration ongoingIF-Processor Pre-processor ready, IF readyBackends AOS and CTS delivered/ work fineBWO-LO Works fine at 1.9THzSolid-State LO 1.4THz was operated at the APEX-telescopeSolid-State LO 1.9THz First testsresults @ 1.9THz Solid-State LO 2.7THz Design readyLaser-LO Not first flight, final assembly startedSoftware In use at KOSMA 3mAirworthiness got positive first airworthiness reportICP submitted (document package)

Comments: M-Band Solid-State-LO technical risk (not short science)

GREAT L-L configuration passed its PSR in Dec. 2008 and is ready for shipment

SOFIA schedule

SITR April 2009; Page 4

MPIfRKOSMAMPSDLR-Berlin

S. Heyminck, MPIfR

GREAT in L-L configuration

Power distributor

Monitor drawler

Ethernet-HUB

Obs-computer

IF-Power-supply

IF Pre-processor

IF LO-supply

IF-processor

Chopper control

SOFIA PI-rack

AOS-system

CTS #1 and #2

FFTS (see talk W4D)

Oscilloscope

LO-synthesizer #1

Optics control

Instrument computer

Mixer-BIAS #1 & #2

Power-supply

LO-synthesizer #2

1.9 THz Solid-state LO

1.4 THz Solid-state LO

Cryostats

SI mounting flange

Cold-load

Picture taken by DLR

SITR April 2009; Page 5

MPIfRKOSMAMPSDLR-Berlin

S. Heyminck, MPIfR

Software

frontend software allows fully remote hardware access offers

a debugging GUI monitoring all software tasks an online database storing all available house-

keeping data a user GUI for easy instrument handling a KOSMA file I/O interface a Perl interface for individual hardware

programming a hardware simulation mode for development

and debugging

well tested during the PSR-tests

Obs-Software “KOSMA-control” in use at KOSMA and Nanten II well tested and understood

SITR April 2009; Page 6

MPIfRKOSMAMPSDLR-Berlin

S. Heyminck, MPIfR

Cart

GREAT Cartfulfills all ICDs

SITR April 2009; Page 7

MPIfRKOSMAMPSDLR-Berlin

S. Heyminck, MPIfR

Ready for Shipment

GREAT was ready for shipment by end of February as required to meet the last project schedule

customized shipping boxes availablemain-structure + cart + LOsfour boxes for cryostats aluminum boxes for electronics/ tools

Picture: GREAT main structure shipping box waiting to be stored

SITR April 2009; Page 8

MPIfRKOSMAMPSDLR-Berlin

S. Heyminck, MPIfR

L#2: performance goody

Best noise-performance we measured so far !

uncorrected receiver noise performance measured at 1821GHz LO frequency

SITR April 2009; Page 9

MPIfRKOSMAMPSDLR-Berlin

S. Heyminck, MPIfR

Ongoing developments

increase usable RF-bandwidthnew HEB-mixernew cold amplifier with better matching to the mixer

no isolator required (isolator is limiting bandwidth so far)

first tests are currently ongoing in Cologne

build-up of the M-band channel (2.7THz)optics and cryostat are readyLO under development

SITR April 2009; Page 10

MPIfRKOSMAMPSDLR-Berlin

S. Heyminck, MPIfR

Schedule towards S/S flights

Schedule counts backwards from first science flight date:

start of GREAT short science period (end of May 2010)

-4 weeks schedule reserve to solve unexpected problems

-2 weeks install GREAT, EMI-test, line-Obs

-4 weeks schedule reserve to solve unexpected problems

-2 weeks re-integration and post shipment inspection

-1 weeks schedule reserve for delays during shipment

-2 weeks shipping the instrument to Palmdale

-1 weeks de-integration and packing

-8 weeks pre-shipment testing (e.g. test new mixers)

(in total 24 weeks)