Planck Pre-Launch Status Papers - APC - UniversitÃ© Paris Diderot ...

More documents

Recommendations

Info

A&A 520, A9 (2010)Table 6. Basic characteristics of the 4 K cooler.Working fluidMaximum cooling power at 17.5 K pre-cooling temperatureRequired cooling power at 17.5 K pre-cooling temperaturePre-cooling stagesNominal operating temperatureMassCompressors, pipes, cold stage, ...Electronics and current regulatorPower4 He19.2 mW13.3 mWThird V Groove 54 K Sorption cooler LR3 17.5–19 K4.5 K27.7 kg8.6 kg120 W Max into current regulatorTable 7. Helium flow.Flows flow 4 He Ftot (DN3+DN4) flow 3 Heµmol/s µmol/s µmol/sFMIN2 14.5 19.8 5.4FMIN 16.6 22.9 6.3FNOM1 20.3 27.8 7.5FNOM2 22.6 30.8 8.2– the heat load from the bolometer plate at a temperatureof T bolo and from the 1.6 K JT stage at a temperatureof T JT1.6 K ;– the temperature of the dilution T dilu .This margin is given byFig. 19. View of the focal plane unit showing the thermal interfaces andthe location of the heating belts and of the thermometers.thermometers L1 and L2 monitor withhighaccuracythetemperatureat this stage, which can be used to correct the 30 GHzand 44 GHz reference load signals.5.3. The dilution coolerThe dilution cooler operates on an open circuit using a largequantity of 4 He and 3 He stored on board in four high pressuretanks. It includes a JT expansion valve producing coolingpower for the 1.6 K stage of the FPU and pre-cooling forthe dilution cooler. The microgravity dilution cooler principlewas invented and tested by Benoît (Benoît et al. 1997) anddeveloppedinto a space-qualified system by DTA Air Liquide(Triqueneaux et al. 2006). The gas from the tanks (at 300 bars atthe start of the mission) is brought down to 19 bars through twopressure regulators, and the flows through the dilution circuit areregulated by a set of discrete restrictions, which can be chosenby telecommand.The helium isotope flow rates for the different configurationsof the restrictions are given in Table 7.The heat lift margin HLm available for temperature regulationis determined by– the He isotopes flow (HeFlow in µmol s −1 )givenbytherestrictionconfiguration for 273 K temperature of the dilutioncooler control unit (DCCU);– the temperature of the DCCU T DCCU in flight;HLm[nW] = 3.2 × 10 −3 HeFlow × T 2 dilu × (T DCCU/273 − 1) 1.5− 250 (T JT1.6 K − 1.28)− 20 (T bolo − T dilu )− 490 nW (parasitic heat load).This allows for operation in flight at the lowest flow (FMIN2) atatemperatureof98mKand108nWofpoweravailableforregulation,even at the highest temperature of the dilution panel in thespacecraft (18 ◦ C). This should provide 32 months of operationsafter cool down.5.4. Thermal architectureIn order to reach the required thermal stability on each thermalstage, a thermal architecture was designed on the 4 K, 1.6 Kand 100 mK stages (Piat et al. 2003). Temperature fluctuationsare measured with very sensitive thermometers made of optimisedNTD Ge (Piat et al. 2001, 2002)andreadoutbythesameelectronics as for the bolometers. Heating power could be appliedwith dedicated heaters controlled with a 24 bits DAC.Details on the temperature stability tests and results are givenin Pajot et al. (2010).5.4.1. 4 K and 1.6 K stagesThe temperature of the 4 K box is regulated by a proportionalintegral-derivative(PID) servo system with a heating belt onthe 4 K box providing a temperature stability so that the powerspectrum temperature fluctuation is lower than 10 µK Hz −0.5 inthe useful band of observation in Planck (0.016 Hz to 100 Hz)(Leroy et al. 2008).An equivalent PID servo system controls the stability ofthe 1.6 K screen of the FPU, with a stability better than thePage 16 of 20
J.-M. Lamarre et al.: Planck pre-launch status: the HFI instrumentFig. 21. Simulation of the gradients induced on the bolometer plate byparticles when the PID is off.Fig. 20. Thermal architecture of the 100 mK stage.requirement of 28 µK Hz −0.5 (in the 0.016 Hz to 100 Hz frequencyrange). For both the 4 K and 1.6 K stages, the requiredstabilities were achieved during system tests as discussed in detailby Pajot et al. (2010).5.4.2. 100 mK stageThe temperature stability of the bolometer plate is achieved withboth an active control and a passive thermal filter as shown inFig. 20 (Piat 2000; Piat et al. 2000).Two stages of PID regulation are included. The first one(PID1) is on the dilution itself and provides stability on long timescales. When no thermal perturbation is applied to the bolometerplate, PID1 alone provides the required stability. The secondregulation system (PID2) is on the bolometer plate. The passivethermal filter is mounted between the dilution cold tip andthe bolometer optical plate. The mechanicallinkbetweenthesetwo stages is built from a material made of an holmium-yttrium(HoY) alloy with high heat capacity at 100 mK. It gives a thermaltime constant of several hours between these stages (Madet2002).The behaviour of the 100 mK part of HFI was extensivelymodelled. The heat input expected on the bolometer plate are theinput from the bias current of the bolometers (less than 1 nW),the microwave radiation reaching the bolometers (0.12 nW),cosmic rays that penetrate the FPU box and deposit energy inthe bolometer plate (0.2 nW), the heat dissipated by microvibrationsin the bolometer plate, and heating from the PID2(about 1 mK temperature increase for 30 nW).Micro-vibrations from the 4 K compressors can add extraheating power on the 100 mK bolometer plate (as was seen duringthe instrument and system tests). The average amount of heatdissipated in the bolometer plate was around 10 nW in the instrumenttests and 40 nW during some periods of the system testsat CSL.Figure 21 shows an example of the predicted gradients onthe bolometer plate when the PID is off. ThethreeHoYlinksto the dilution cooler are seen as the blue (cold) spots throughwhich the heat from the cosmic rays and bolometer bias currentdissipation is transferred towards the dilution stage. The yellowareas are due to recent cosmic rays hits. If the PID2 is turnedon with a typical heat input of 100 nW, the gradients will be300 times steeper. When the heat input varies, the top of theHoY feet will readjust very slowly because of their long timeconstants. The gradient will change accordingly. It is thus believedthat using the PID2 will not improve the temperature stabilityof the bolometer plate for rapid changes of heat inputs. Theslow drifts are damped by PID1 on the dilution plate. Thus PID2is considered as a back-up of PID1 and will not be used in flight.The main temporary perturbations on the 100 mK stageshould come from solar flares. Only a few events at most areexpected during the mission leading to the loss of a few days ofoperation of the dilution cooler.6. Model philosophy and calibrations6.1. Model philosophyThe Planck spacecraft (S/C) development philosophy was basedon two models, the qualification model and the Planck Flightmodel (equipped with the flight models of the instruments).The HFI followed the same approach. The testing programmeof the S/C imposedacryogenicverificationmodelinadditionto the usual space qualification. This was called the CryogenicQualification Model (CQM). The S/C CQMwasrequiredtobeidentical to the PFM for the cold part (PPLM) and similar forthe SVM. The goal was to verify as far as necessary the conceptof the entire cryogenic chain andassociatedancillaryunits.TheHFI model philosophy, numbering and naming were the same,with a CQM HFI partly composed of flight units, or candidatesto be swapped with flight ones later on or to be used as spareunits for the PFM. The qualification of HFI followed a standardtesting sequence for the warm units in compliance with theenvironmental conditions imposed by the mission through theS/C interfaces.AmajorstepfortheHFIwastheperformanceverification of the FPU including the cold parts of the 1.6 K and100 mK of the dilution cooler, equipped with a limited number ofoptical channels. This test allowed the validation and the characterizationof the whole detection chain in a thermal configurationidentical to the flight one, i.e. bolometers at 100 mK, cold filtersat 100 mK, 1.6 K, and 4 K, JFET preamplifier at 110 K, andPage 17 of 20
Page 1 and 2:
A&A 520, E1 (2010)DOI: 10.1051/0004
Page 3 and 4:
ABSTRACTThe European Space Agency
Page 5 and 6:
A&A 520, A1 (2010)Fig. 2. An artist
Page 7 and 8:
A&A 520, A1 (2010)Fig. 4. Planck fo
Page 9 and 10:
A&A 520, A1 (2010)Fig. 6. The Planc
Page 11 and 12:
A&A 520, A1 (2010)Table 4. Summary
Page 13 and 14:
A&A 520, A1 (2010)three frequency c
Page 15 and 16:
A&A 520, A1 (2010)Fig. 12. The left
Page 17 and 18:
A&A 520, A1 (2010)Fig. 14. Left pan
Page 19 and 20:
A&A 520, A1 (2010)flux limit of the
Page 21 and 22:
A&A 520, A1 (2010)- University of C
Page 23 and 24:
A&A 520, A1 (2010)57 Instituto de A
Page 25 and 26:
A&A 520, A2 (2010)Fig. 1. (Left) Th
Page 27 and 28:
A&A 520, A2 (2010)Fig. 3. (Top)Twos
Page 29 and 30:
A&A 520, A2 (2010)Table 2. Predicte
Page 31 and 32:
Table 3. Predicted in-flight main b
Page 33 and 34:
A&A 520, A2 (2010)materials. Theref
Page 35 and 36:
A&A 520, A2 (2010)Fig. 11. Comparis
Page 37 and 38:
A&A 520, A2 (2010)Table 5. Inputs u
Page 39 and 40:
A&A 520, A2 (2010)Fig. 16. Three cu
Page 41 and 42:
A&A 520, A2 (2010)Table 7. Optical
Page 43 and 44:
A&A 520, A2 (2010)Fig. A.1. Dimensi
Page 45 and 46:
A&A 520, A2 (2010)5 Università deg
Page 47 and 48:
A&A 520, A3 (2010)Horizon 2000 medi
Page 49 and 50:
A&A 520, A3 (2010)Fig. 1. CMB tempe
Page 51 and 52:
A&A 520, A3 (2010)Ω ch 2τn s0.130
Page 53 and 54:
A&A 520, A3 (2010)Fig. 6. Integral
Page 55 and 56:
A&A 520, A3 (2010)Table 2. LFI opti
Page 57 and 58:
3.3.1. SpecificationsThe main requi
Page 59 and 60:
A&A 520, A3 (2010)Fig. 11. Schemati
Page 61 and 62:
A&A 520, A3 (2010)features of the r
Page 63 and 64:
A&A 520, A3 (2010)Fig. 13. Level 2
Page 65 and 66:
A&A 520, A3 (2010)Fig. 15. Level 3
Page 67 and 68:
A&A 520, A3 (2010)GUI = graphical u
Page 69 and 70:
A&A 520, A3 (2010)23 Centre of Math
Page 71 and 72:
A&A 520, A4 (2010)In addition, all
Page 73 and 74:
A&A 520, A4 (2010)Table 2. Sensitiv
Page 75 and 76:
A&A 520, A4 (2010)Fig. 2. Schematic
Page 77 and 78:
A&A 520, A4 (2010)Fig. 6. LFI recei
Page 79 and 80:
A&A 520, A4 (2010)Fig. 9. Schematic
Page 81 and 82:
A&A 520, A4 (2010)Table 4. Specific
Page 83 and 84:
A&A 520, A4 (2010)Fig. 15. DAE bias
Page 85 and 86:
A&A 520, A4 (2010)Fig. 19. Picture
Page 87 and 88:
A&A 520, A4 (2010)Table 10. Main ch
Page 89 and 90:
Table 13. Principal requirements an
Page 91 and 92:
A&A 520, A5 (2010)DOI: 10.1051/0004
Page 93 and 94:
A. Mennella et al.: LFI calibration
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
D.1. Step 1-extrapolate uncalibrate
Page 107 and 108:
A&A 520, A6 (2010)DOI: 10.1051/0004
Page 109 and 110:
F. Villa et al.: Calibration of LFI
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
A&A 520, A7 (2010)DOI: 10.1051/0004
Page 123 and 124: M. Sandri et al.: Planck pre-launch
Page 126 and 127: A&A 520, A7 (2010)Fig. 8. Footprint
Page 128 and 129: -30-40-30-6-3-20A&A 520, A7 (2010)0
Page 130 and 131: A&A 520, A7 (2010)Table 4. Galactic
Page 132 and 133: A&A 520, A7 (2010)Fig. A.1. Polariz
Page 134 and 135: A&A 520, A8 (2010)inflation, giving
Page 136 and 137: A&A 520, A8 (2010)estimated from th
Page 138 and 139: A&A 520, A8 (2010)ways the most str
Page 140 and 141: unmodelled long-timescale thermally
Page 142 and 143: A&A 520, A8 (2010)Fig. 5. Polarisat
Page 144 and 145: A&A 520, A8 (2010)Table 3. Band-ave
Page 146 and 147: A&A 520, A8 (2010)where S stands fo
Page 148 and 149: A&A 520, A8 (2010)Fig. 11. Simulate
Page 150 and 151: stored in the LFI instrument model,
Page 152 and 153: A&A 520, A8 (2010)Table 5. Statisti
Page 154 and 155: A&A 520, A8 (2010)comparable in siz
Page 156 and 157: A&A 520, A8 (2010)Table B.1. Main b
Page 158 and 159: A&A 520, A8 (2010)Bond, J. R., Jaff
Page 160 and 161: A&A 520, A9 (2010)- (v) an optical
Page 162 and 163: A&A 520, A9 (2010)Fig. 2. The Russi
Page 164 and 165: A&A 520, A9 (2010)Table 3. Estimate
Page 166 and 167: A&A 520, A9 (2010)Fig. 7. Picture o
Page 168 and 169: A&A 520, A9 (2010)Fig. 9. Cosmic ra
Page 170 and 171: A&A 520, A9 (2010)Fig. 13. Principl
Page 172 and 173: A&A 520, A9 (2010)Fig. 16. Noise sp
Page 176 and 177: A&A 520, A9 (2010)with warm preampl
Page 178 and 179: A&A 520, A9 (2010)20 Laboratoire de
Page 180 and 181: A&A 520, A10 (2010)Table 1. HFI des
Page 182 and 183: A&A 520, A10 (2010)based on the the
Page 184 and 185: A&A 520, A10 (2010)Fig. 6. The Satu
Page 186 and 187: A&A 520, A10 (2010)5. Calibration a
Page 188 and 189: A&A 520, A10 (2010)Fig. 16. Couplin
Page 190 and 191: A&A 520, A10 (2010)217-5a channel:
Page 192 and 193: A&A 520, A10 (2010)10 -310 -495-The
Page 194 and 195: A&A 520, A11 (2010)DOI: 10.1051/000
Page 196 and 197: P. A. R. Ade et al.: Planck pre-lau
Page 202 and 203: A&A 520, A12 (2010)Table 1. Summary
Page 204 and 205: arrangement was also constrained by
Page 206 and 207: A&A 520, A12 (2010)frequency cut-of
Page 208 and 209: A&A 520, A12 (2010)Fig. 9. Gaussian
Page 210 and 211: A&A 520, A12 (2010)the horn-to-horn
Page 212 and 213: A&A 520, A12 (2010)Fig. 15. Composi
Page 214 and 215: A&A 520, A12 (2010)Fig. 19. Broad-b
Page 216 and 217: A&A 520, A13 (2010)DOI: 10.1051/000
Page 218 and 219: C. Rosset et al.: Planck-HFI: polar
Page 220 and 221: C. Rosset et al.: Planck-HFI: polar
Page 222 and 223: of frequencies and shown to have po
Page 224 and 225:
C. Rosset et al.: Planck-HFI: polar
Page 226 and 227:
C. Rosset et al.: Planck-HFI: polar
show all

Planck Pre-Launch Status Papers - APC - UniversitÃ© Paris Diderot ...

Create successful ePaper yourself

Delete template?

Save as template?