A 279-381 GHz receiver for the new APEX telescope ISTT 2005 Chalmers, GöteborgMay 2-4, 2005 A 279-381 GHz SIS receiver for the APEX telescope C. Risacher

A 279-381 GHz receiver for the new APEX telescope

ISTT 2005 Chalmers, GöteborgMay 2-4, 2005

A 279-381 GHz SIS receiver A 279-381 GHz SIS receiver for the APEX telescopefor the APEX telescope

C. Risacher1, V. Belitsky1, I. Lapkin2, R. R. Monje1, V. Vassilev1, M . Pantaleev1, A. Pavolotsky1, K.-Å Johansson1, L. G. Gunnarsson1, M. Svensson1, M. Fredrixon1, E.

Sundin1, V. P. Robles1, D. Medelin, M.Hagström 1, R. Booth 1

1 Group for Advanced Receiver Development (GARD), Radio & Space Science Department with Onsala Space Observatory, Chalmers University of

Technology, Gothenburg, Sweden2 Institute of Applied Physics, Russian Academy of Sciences

46 Ulyanov str.,603950 Nizhny Novgorod, Russia



Band RF range (GHz) IF (GHz) DSB Noise

APEX-1 G: 211-275 4-8 G: 25K

B: 40K

APEX-2 G: 275-370 4-8 G: 35K

B: 50K

APEX-3 G: 385-500

B: 455-500

4-8 G: 70K

B: tbd

APEX-4 G: 602-720 4-8 G: 110K

B: 170K

APEX-5 G: 787-950 4-8 G: 175K

B: tbd

APEX-T1 G: 1030 (50) 4-8 G: 230 K

APEX-T2 G: 1320 (140) tbd G: 550 K

APEX-T3 G: 1500 (140) tbd G: 650 K

APEX receivers: Heterodyne InstrumentationAPEX receivers: Heterodyne Instrumentation



RF tuning range: 279-381 GHz (no possibilities to extend this range except by changing the Gunn oscillator.

IF frequency: 4-8 GHz. At the present time the backend are limiting the IF band to 5-7 GHz

Noise temperature:

40 ± 10 K (DSB) across RF band

Optics Flat and active cold mirrors + 9 warm mirrors to obtain a beamwaist of 6 mm to match the APEX Cassegrain waist

Cryogenics Old SEST SESIS cryostat. Closed cycle cooling system. 1 compressor CTI 8500 with cold head CTI1020 to produce 80K and 12K. 1

compressor Quantum J20 for 4K stage. Cooling time of 14 hours.

Calibration External calibration unit in Cabin A: See corresponding documentation

Computer control

Control system using National Instrument Fielpoint modules. Ethernet connection to the telescope network. Virtually possible to tune from

anywhere.

Alarms If temperature of mixer block exceed 4.9 K, automatic shutdown of the receiver. Bias of SIS is set to 0 mV, and magnetic coil current is

also set to 0 mA.



230 GHz channel 345 GHz channel

Outside part of cryostat Inner part of cryostat

First light receiver with closed cycle machine



Signal from input window

Flat mirror

Active mirror

Mixer block

4-8 GHz LNA







780

mm

400mm

Nasmyth flange

Horn apertureposition

ellipsoid mirror

switching active mirrorFocal distance 660mm





Laboratory test cryostat with liquid helium

Mixer block

4-8 GHz Isolator 4-8 GHz IF LNA

Cold teflon lens

200 m Zitex IR filter

3 mm Teflon window with

circular corrugations



Mixer block description









0

50

100

150

200

240 260 280 300 320 340 360 380

Uncorrected noise temperature for 4 mixer blockswith twin junctions 30 Ohm probe

MB2-n

MB2-o

MB1-n

MB1 - n

No

ise

te

mp

era

ture

(K

)

LO frequency (GHz)

3*hu/ k

2*hu/ k

Apex band 2

Toptics 12 K

Loptics 5%

TIF 10-20 K

Gmix 0 - 3 dB

Tmix 10 K







0 mA coil current : Strong DC Josephson effect



12.5 mA coil current : DC Josephson effect suppressed



With LO power applied



Control system





Cooling system







0

50

100

150

200

250

300

0 5 10 15 20

Apex first light receiver cool down16-12-04

77 K stage20 K stage4 K stage

Te

mp

era

ture

(K

)

Time (Hours)

Documents

A 279-381 GHz receiver for the new APEX telescope ISTT 2005 Chalmers, GöteborgMay 2-4, 2005 A 279-381 GHz SIS receiver for the APEX telescope C. Risacher