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 This page summarizes the present instrumentation at the 30m observatory. The current status is described on another [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus page].
'''THIS PAGE IS STILL UNDER CONSTRUCTION''' For the moment, please use the old [http://www.iram.es/IRAMES/telescope/telescopeSummary/telescope_summary.html Telescope System Summary page] [[BR]]



This page summarizes the present instrumentation at the 30m observatory. [[BR]] The current status is described on another [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus page].
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==== A,B,C,D single pixel receivers ====
A maximum of four receivers, from the total of eight, can be used simultaneously. The following table summarizes the allowed combinations and some of the most important receiver characteristics. Plots of the receiver characteristics.
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==== HERA 3x3 dual-polarisation 1.2mm array ====
HERA cannot be combined with other receivers; up to now not all frequencies have been pretuned. Hera has 18 pixels separated by 24". Local contact for HERA: Albrecht Sievers		  * Eight single pixel, dual-sideband receivers A,B,C,D, and the 3x3 dual-polarisation HERA receiver are installed.
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||'''Rx''' ||'''Pol'''|| || || || || '''tuning range''' || '''Trx''' || '''IF''' || '''IF Bw''' || '''Gim''' || '''Remarks''' ||
|| || || || || || || '''[GHz]''' || '''[K]''' || '''[GHz]''' || '''[GHz]''' || '''[dB]''' || ||
||A100 || V || X || || X || || 80.0-115.5 || 60-80 || 1.5 || 0.5 || >20 || 1. ||
||B100 || H || X || || || X || 81.0-115.5 || 60-85 || 1.5 || 0.5 || >20 || ||
||C150 || V || || X || || X || 130-183 || 70-125 ||            || || || ||
||D150 || H || || X || X || || 130-183 || 80-125 ||            || || || ||
||A230 || V || X || || X || || 197-266 || 85-150 ||            || || || ||
||B230 || H || X || || || X || 197-266 || 95-160 ||            || || || ||
||C270 || V || ||   || || || 241-281 || 125-250 ||            || || || ||
||D270 || H || ||   || || || 241-281 || 150-250 ||            || || || ||
||HERA || H || || || || || 215-272 || 110-380 ||            || || || ||
||HERA || V || || || || || 215-241 || 120-340 ||            || || || || 		 * Four of the 8 A,B,C,D receivers can be used simultaneously. HERA cannot be combined with other receivers.

||'''Rx''' ||'''Pol'''|| || || || || ||'''tuning range''' || '''Trx''' || '''IF''' || '''IF Bw''' || '''Gim''' || '''Remarks''' ||
|| || || || || || || ||'''[GHz]''' || '''[K]''' || '''[GHz]''' || '''[GHz]''' || '''[dB]''' || ||
||A100 || V || X || || X || || ||(72-)80.0-115.5 || 60-80 || 1.5 || 0.5 || >20 || '''1. '''||
||B100 || H || X || || || X || ||(72-)81.0-115.5 || 60-85 || 1.5 || 0.5 || >20 || '''1.'''||
||C150 || V || || X || || X || ||130-183 || 70-125 || 4 || 1 || 15-25 || ||
||D150 || H || || X || X || || ||130-183 || 80-125 || 4 || 1 || 08-17 || ||
||A230 || V || X || || X || || ||197-266 || 85-150 || 4 || 1 || 12-17 || ||
||B230 || H || X || || || X || ||197-266 || 95-160 || 4 || 1 || 12-17 || ||
||C270 || V || || X || || X || ||241-281 || 125-250 || 4 || 1 || 10-20 || '''2.'''||
||D270 || H || || X || X || || ||241-281 || 150-250 || 4 || 1 || 9-13 || '''2.'''||
||HERA1 || H || || || ||  || X || 215-272 || 110-380 || 4 || 1 || ~10 || '''2.,3.'''||
||HERA2 || V || || || ||  || X || 215-241 || 120-340 || 4 || 1 || ~10 || '''2.,3.'''||
 
'''Remarks:'''
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 1. 2x(3x3) pixel receiver with a 24" separation of the pixels. Equipped with a derotator allowing to follow a source in the sky maintaining the same "footprint".  1. [http://www.iram.es/IRAMES/mainWiki/HeraWebPage More information on HERA ]
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Table
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local contact for bolometers: Stephane Leon || Bolometer || Beam || Lambda|| Pixels || Spacing || rms (1.) ||
|| MAMBO I || 11"|| 1.2 mm || 37 || 20" || 1.5 mJy||
||MAMBO II || 11" || 1.2 mm || 117 || 20" || 1.5 mJy||

 1. rms after 10 minutes (normal bolometric conditions) with skynoise removal.
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Below you find the most recent values for the forward and beam efficiencies. We have also compiled the value of the efficiencies in the past .
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Here you can find the plot with the most recently measured beam efficiencies.  * Below you find the most recent values for the forward and beam efficiencies. We have also compiled the [http://www.iram.es/IRAMES/telescope/telescopeSummary/effi_history.html value of the efficiencies in the past].
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Table  * Here you can find the [http://www.iram.es/IRAMES/telescope/telescopeSummary/beam_effis.html plot of efficiencies measured in 2000]. A more recent compilation can be found in the Annual Report 2007.
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1) The HPBW can be well fit by: HPBW('') = 2460/freq(GHz). '' || freq || HPBW || B_eff || S/TA* ||
|| (GHz) || (arcsec) || (%) || (Jy/K) ||
|| || (1) || (2) || (3) ||
||72 (extrapolated) || 34 || 79 || 6.0 ||
||77 (extrapolated) || 32 || 79 || 6.0 ||
||86 ||29 || 78 || 6.0 ||
||110 || 22 || 75 || 6.3 ||
||145 || 17 || 69 || 6.7 ||
||170 || 14.5 || 65 || 7.1 ||
||210 || 12 || 57 || 7.9 ||
||235 || 10.5 || 52 || 8.7 ||
||260 || 9.5 || 46 || 9.5 ||
||279 || 9 || 42 || 10.4 ||
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''2) The data can be well fit by a Ruze function B_eff = 1.2 epsilon exp[-(4pi R sigma/ lambda)^2] with sigma being the rms value of the telescope optics deformations, R the reduction factor for a steep main reflector, epsilon the aperture efficieny of the perfect telescope and lambda the wavelength in mm. The data can be fit by R*sigma = 0.07 and epsilon = 0.69. The aperture efficiency of the 30-m telescope can be obtained using eta_a=B_eff*0.79 ''  1. The half power beam width, HPBW, can be well fitted by: HPBW/arcsec = 2460/freq/GHz.
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''3) For a Gaussian source and beam size, and a source which is much smaller than the beam, S(Jy)/T_mb(K)=8.18E-7*theta(")^2*nu(GHz)^2 (Rohlfs & Wilson, Tools of Radioastronomy (2. ed., Eq. 8.20). Using the approximation in 1) yields for the 30-m telescope S/T_mb=4.95 Jy/K. S/T_A* is obtained by multiplying 4.95 J/K with F_eff/B_eff ''  1. Main beam efficiency B _eff. The data can be well fit by a Ruze function B_eff = 1.2 epsilon exp[-(4pi R sigma/ lambda)^2] with sigma being the rms value of the telescope optics deformations, R the reduction factor for a steep main reflector, epsilon the aperture efficieny of the perfect telescope and lambda the wavelength in mm. The data can be fit by R*sigma = 0.07 and epsilon = 0.69. The aperture efficiency of the 30-m telescope can be obtained using eta_a=B_eff*0.79

 1. Point source sensitivity S/T_A*. For a Gaussian source and beam size, and a source which is much smaller than the beam, S(Jy)/T_mb(K)=8.18E-7*theta(")^2*nu(GHz)^2 (Rohlfs & Wilson, Tools of Radioastronomy (2. ed., Eq. 8.20). Using the approximation in 1) yields for the 30-m telescope S/T_mb=4.95 Jy/K. S/T_A* is obtained by multiplying 4.95 J/K with F_eff/B_eff ''

Anchor(beginOfPage)

THIS PAGE IS STILL UNDER CONSTRUCTION For the moment, please use the old [http://www.iram.es/IRAMES/telescope/telescopeSummary/telescope_summary.html Telescope System Summary page] BR

This page summarizes the present instrumentation at the 30m observatory. BR The current status is described on another [http://www.iram.es/IRAMES/mainWiki/TelescopeSystemStatus page].

TableOfContents(4)

Frontends

Heterodyne Receivers

  • Eight single pixel, dual-sideband receivers A,B,C,D, and the 3x3 dual-polarisation HERA receiver are installed.
  • Four of the 8 A,B,C,D receivers can be used simultaneously. HERA cannot be combined with other receivers.

Rx

Pol

tuning range

Trx

IF

IF Bw

Gim

Remarks

[GHz]

[K]

[GHz]

[GHz]

[dB]

A100

V

X

X

(72-)80.0-115.5

60-80

1.5

0.5

>20

1.

B100

H

X

X

(72-)81.0-115.5

60-85

1.5

0.5

>20

1.

C150

V

X

X

130-183

70-125

4

1

15-25

D150

H

X

X

130-183

80-125

4

1

08-17

A230

V

X

X

197-266

85-150

4

1

12-17

B230

H

X

X

197-266

95-160

4

1

12-17

C270

V

X

X

241-281

125-250

4

1

10-20

2.

D270

H

X

X

241-281

150-250

4

1

9-13

2.

HERA1

H

X

215-272

110-380

4

1

~10

2.,3.

HERA2

V

X

215-241

120-340

4

1

~10

2.,3.

Remarks:

  1. Using a special external LO, frequencies down to 77 GHz can be measured with good sideband rejection. For frequencies below 77 GHz, the sideband recection becomes weaker, and the sideband ratio reaches unity at 72 GHz
  2. Noise increasing with frequency

  3. [http://www.iram.es/IRAMES/mainWiki/HeraWebPage More information on HERA ]

Bolometers

Bolometer

Beam

Lambda

Pixels

Spacing

rms (1.)

MAMBO I

11"

1.2 mm

37

20"

1.5 mJy

MAMBO II

11"

1.2 mm

117

20"

1.5 mJy
  1. rms after 10 minutes (normal bolometric conditions) with skynoise removal.

Efficiencies and Half-power beam width

freq

HPBW

B_eff

S/TA*

(GHz)

(arcsec)

(%)

(Jy/K)

(1)

(2)

(3)

72 (extrapolated)

34

79

6.0

77 (extrapolated)

32

79

6.0

86

29

78

6.0

110

22

75

6.3

145

17

69

6.7

170

14.5

65

7.1

210

12

57

7.9

235

10.5

52

8.7

260

9.5

46

9.5

279

9

42

10.4

  1. The half power beam width, HPBW, can be well fitted by: HPBW/arcsec = 2460/freq/GHz.
  2. Main beam efficiency B _eff. The data can be well fit by a Ruze function B_eff = 1.2 epsilon exp[-(4pi R sigma/ lambda)^2] with sigma being the rms value of the telescope optics deformations, R the reduction factor for a steep main reflector, epsilon the aperture efficieny of the perfect telescope and lambda the wavelength in mm. The data can be fit by R*sigma = 0.07 and epsilon = 0.69. The aperture efficiency of the 30-m telescope can be obtained using eta_a=B_eff*0.79

  3. Point source sensitivity S/T_A*. For a Gaussian source and beam size, and a source which is much smaller than the beam, S(Jy)/T_mb(K)=8.18E-7*theta(")2*nu(GHz)2 (Rohlfs & Wilson, Tools of Radioastronomy (2. ed., Eq. 8.20). Using the approximation in 1) yields for the 30-m telescope S/T_mb=4.95 Jy/K. S/T_A* is obtained by multiplying 4.95 J/K with F_eff/B_eff

Table

4) The values for F_eff are valid after the 12th of December 2000 when a new reflecting ring was put around the secondary mirror. The moon efficiencies are equal to forward efficiencies (Kramer et al. 1997).

Backends

Spectrometers

Table

Bolometer backends

Spectral Line Observing Modes

  • Position switching: only relative OFF positions possible (radio projection offsets).

  • Wobbling secondary: max. 240" throw at 0.25 Hz, standard phase duration 0.5 Hz.

  • Frequency switching: max. 45 km/s throw at max. 0.5 Hz., with 100 kHz filters and autocorrelator only

  • On the fly mapping: Works with all receiver and backends, typical dump rate 0.5-1 Hz

  • Polarimetry: using VESPA as an IF polarimeter

  • Pointing: Using nearby (within 10 degree) pointing sources, <1" accuracy can be obtained; with absolute ("blind") pointing, the accuracy is <4", the receivers are usually aligned within 2". Checking the pointing and alignment (using e.g. a planet) is the responsibility of the observer.

  • Focus: residual errors of <1mm may need correction. There may be systematic differences (<0.4") in the focus of the different receivers. Check focus at least at after sunrise and sunset.

TelescopeSystemSummary (last edited 2009-07-07 13:46:21 by visitor4)