POST and Dome A FTS status(Mitaka 2010) - 大阪府立大学 · 2011. 5. 27. · FTS: Working...
Transcript of POST and Dome A FTS status(Mitaka 2010) - 大阪府立大学 · 2011. 5. 27. · FTS: Working...
Status of POST and Dome A Status of POST and Dome A
FTS SystemFTS System
Yao Yao QijunQijun (([email protected]@mwlab.pmo.ac.cn))
Millimeter & SubMillimeter & Sub--millimeter Laboratorymillimeter Laboratory
Purple Mountain Observatory, CASPurple Mountain Observatory, CAS
The POSTThe POST--POPOrtablertable SSubub--millimeter millimeter
TTelescope (introduction)elescope (introduction)►►300mm off300mm off--axis parabolic, 8axis parabolic, 8’’ beam width beam width
@500GHz@500GHz
►►AzAz--EL driving by Harmonic DriveEL driving by Harmonic Drive®® gear and gear and
AC servo motorAC servo motor
►►SIS heterodyne receiver with 2SIS heterodyne receiver with 2--bits 500MHz bits 500MHz
autocorrelation spectrum analyzerautocorrelation spectrum analyzer
►►100mW 4K close100mW 4K close--cycle cooler with 1.2kW cycle cooler with 1.2kW
single phase 100V ACsingle phase 100V AC
The POST: system layoutThe POST: system layout
Tsys < 200K
Better stability
due to less
Josephson effect
High Tc relaxed
cooling requirement
POST 0.5THz NbN SIS mixer & Observed CO (J=4-3),
(cooperated with NICT, Japan)
The POST: 0.5THz NbN SIS Mixer1st Astronomical observation ever made with an NbN SIS mixer(2008)
The POST: The POST: Receiver Module UpgradeReceiver Module Upgrade
�Mixer block and
Lens aligned by in-axis
mount hole;
�Cooled LNA is
installed close to mixer
to reduce the port
reflection;
�Good thermo-contact
by spring wash locked
back cover
The POST: The POST: LO Module modificationLO Module modification
►►4545°°LO plate LO plate
rotation to give a rotation to give a
inline polarization inline polarization
matching;matching;
►►More space for More space for
tuning knob means tuning knob means
a more easy a more easy
adjustingadjusting
The POST: The POST: Receiver System AssemblingReceiver System Assembling
�LO coupled
through 25um
Kapton film beam-
splitter
�Cold unit directly
mounted on 4K
cold head
The POST: Site survey at Tibet (2008)
The POST: 230GHz FFO+SIS
integrated receiver
►Demonstration of
FFO+SIS single
chip heterodyne
receiver
►Cooperation
between IREE
Russian and
PMO China
FTS: Dome A site survey on THzFTS: Dome A site survey on THz
�Why Dome A for THz:High altitude~4080m; Low temperature ~ High altitude~4080m; Low temperature ~ --6060℃℃ on on
average average �� lowest PWV become possiblelowest PWV become possible
�Challenge to face up��Low ambient temperature Low ambient temperature �� special designspecial design
��~1year unattended operation ~1year unattended operation �� high reliabilityhigh reliability
��LN2 unavailable LN2 unavailable �� precise precise calibrationcalibration
��RT detectors RT detectors �� limited sensitivitylimited sensitivity (high stability)(high stability)
- Why and How?
Design of the FTS System- System Specs
ModeMode Rapid scanRapid scan
Freq. RangeFreq. Range 0.750.75--15THz (15THz (LB: 0.75LB: 0.75--3.5THz, HB: 3.53.5THz, HB: 3.5--
15THz15THz))
Freq. ResolutionFreq. Resolution <10GHz<10GHz
Beam ApertureBeam Aperture >75mm>75mm
DLATGS NEPDLATGS NEP ~10~10--1010W/HzW/Hz0.50.5
Time/SpectrumTime/Spectrum 10mins10mins
MPI VolumeMPI Volume 0.7mx0.7mx0.3m0.7mx0.7mx0.3m
PowerPower <200W<200W
LowLow--bandband HighHigh--bandband
Freq Range (THz)Freq Range (THz) 0.5~3.50.5~3.5 3.5~153.5~15
Resolution (GHz)Resolution (GHz) 1010 1010
Optics EfficiencyOptics Efficiency 0.10.1 0.10.1
Beam Diameter Beam Diameter
(cm)(cm) 7.57.5 7.57.5
Throughput Throughput
(cm(cm22sr)sr)0.7920.792 0.1850.185
Detector Area Detector Area
(cm(cm22))0.1260.126 0.0290.029
Detector NEP Detector NEP
(W/Hz(W/Hz0.50.5))3.5e3.5e--1010 1.7e1.7e--1010
Parameters for Calculation
LB
HB
Based on DLATGS (RT) Based on DLATGS (RT)
detectors to achieve S/N>10detectors to achieve S/N>10
FTS:Estimation of Sensitivity
Design of the FTS System- Optics Calculation for MPI
MPI optics
Zemax
Simulation
The FTS scanning benchThe FTS scanning bench- built by BlueSky
FTS system testing in Lab.
no tipping mechanism
calibrator & snow
cleaning structure
integrated
tilted window + brush
prevent snow on window
air sealed HDPE pipe
window ensure < 20W
heat dispersion
driver & oil specially
chosen for reliability (-
40℃/-90℃)
Design of the FTS System- “Mailbox” Subsystem
FTS: Working status at Dome A
0 2000 4000 6000 8000 10000 12000 14000 16000 18000 200000.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
RAW
Freq(GHz)
01det1.cal
01det1.sky
0 1000 2000 3000 4000 50000.0000
0.0025
0.0050
0.0075
0.0100
RAW
Freq
01det2.sky
01det2.cal
Low band (0.5~3.5THz) 5 minutes scan
spectrum, Feb. 1, 2010. Tamb:-40℃
High band (3.5~15THz) 5 minutes scan
spectrum, Feb. 1, 2010. Tamb:-40℃
ConclusionConclusion
►►A compact 500GHz cooled receiver A compact 500GHz cooled receiver module proved to be a successful designmodule proved to be a successful design
►►THz opacity at Yangbajing site (4300m) THz opacity at Yangbajing site (4300m) has been fist measuredhas been fist measured
►►THz FTS system have been successfully THz FTS system have been successfully deployed on Dome A and working deployed on Dome A and working smoothlysmoothly