The Italian View

of B-Pol

P. de Bernardisand the

Italian team

The Italian HW groups :

• Milano (Bersanelli, Mennella et al.)• Milano Bicocca (Gervasi, Sironi, et al.)• Torino (Tascone et al.)• Bologna (Carretti, Cortiglioni, Mandolesi, Valenziano, Villa, et al.)• Firenze (Natale et al.)• Roma La Sapienza (de Bernardis, De Petris, Masi et al.)

Heritage:

BOOMERanG, Planck-HFI, Planck-LFI, SPORT, Bar-SPORT, OLIMPO

All started in the COFIS study of “Themes and Models in Cosmology and Fundamental

Physics”funded in 2004 by the Italian Space Agency

ASI studies• The Italian Space Agency

has supported in 2004 a study on “Themes and Models in Cosmology and Fundamental Physics from Space”.

• All the members of the Italian cosmology community have contributed to this study, which was delivered on Oct. 20, 2004.

• Top priorities resulting from the study:

Piano Aerospaziale Nazionale 2006-2008 Agenzia Spaziale Italiana

http://www.asi.it/html/ita/news/20060124_Executive_Summary.pdf

Orbit L2 (baseline), LEO or MEO

Scanning strategy Spinning at about 1rpm. TBD

Optics 4 small telescopes (aperture of about 60 cm each); large non distorted focal surface; low sidelobes; low spurious polarisation

Angular resolution 10-20 arc min at 100 GHz (typical)

Frequency range 40-120 GHz (HEMT); 60-220 GHz (Bolometers)

Bandwidth 10% (typical)

Number of detectors 100 to 1000 (sensitivity up to 30 times better than Planck)

Detectors HEMT radiometers (at 20 K) or Bolometers (100-300 mK), TBD

Number of frequencies

3 (HEMT); 3 (Bolometers); 6 (HEMT + Bolometers) TBD

Cryogenics Active and Passive techniques TBD

Bus PRIMA

Data rate Compressed, typically 10 GB per day

Carrier VEGA

Tab. 2‑1: Overview of the driving mission requirements for the B-POL satellite .

EXAMPLE

No real instrument study, yet• Many issues require further experimentation -

thinking.• The most important ones are:

– Mass production of detectors (sensitivity)– Knowledge of polarized foregrounds and optimization of

sky coverage / sky scan– Instrumental Systematics– Polarization modulation

• For these reasons we do not have a full proposal• Here we want to give contributions for discussion

• At variance with interferometers, Bolometer technology is easily scalable, and the throughput can be larger than 2.

• Focal planes hosting thousands of bolometers are being developed already.

• Intense activity in this field is ongoing in Berkeley, JPL-Caltech, Cardiff, SRON …

• How many detectors do we really need for a B-modes survey ?

Sensitivity

A. Lee, Berkeley

r = 0.03FWHM = 0.5°, T=1 yearNET = 150 K/sqrt(Hz)

FWHM = 0.5°T=1 yearNET = 150 K/sqrt(Hz)

500 detectors10000 detectors

50%

Cfr. Challinor & ChonAstro-ph/0410097

Analysis by G. Polenta

Mass production of detectors in Italy

Italian TESs :• GASTALDO L., GALLINARO G., GATTI F., PERGOLESI D., RIBEIRO GOMES

M., REPETTO P., DUSSONI S., VALLE R., MANFRINETTI P., CHINCARINI A. (2006). Study of the δ-Al/Ag superconducting alloy for TES applications. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT. vol. 559 pp. 465-467 ISSN: 0168-9002  2.

• GATTI F., PIRO L., PERGOLESI D., COLASANTI L., GASTALDO L., RIBEIRO GOMES M., REPETTO P. (2006). TES microcalorimeter development for future Italian X-ray astronomy missions. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT. vol. 559 pp. 605-607 ISSN: 0168-9002  

PRIN 2006• We have setup a national collaboration to develop

a large-format, polarization-sensitive bolometer array camera at 90 GHz.

• This is a collaboration of the following groups– Roma (de Bernardis, Masi, Vittorio, Dall’ Oglio) – Milano (Bersanelli, Gervasi)– Genova (Gatti)– Bologna (Mandolesi)– Padova/Trieste (De Zotti – Pasian)

• The camera, based on Horn-coupled TES bolometers, will fill with 300 detectors the corrected focal plane of a 2.6m telescope (we have one in the Alps (MITO), one in Antarctica (COCHISE) and a balloon-borne one (OLIMPO).

Det. architecture, Cryogenics, ReadoutPassive Frontend

TES, wafer processing

Passive frontend

Analysis, science

RICRivelatori a

Induttanza CineticaLa Sapienza - RomaIRST-ITC – Trento

INFN funds+ Cardiff (Mauskopf)

R C

KIDKinetic Inductance

DetectorsLa Sapienza - RomaIRST-ITC – Trento

INFN funds+ Cardiff (Mauskopf)

R C

R C

Mazin (Caltech)

GHz RF (…+fN-1+fN+fN+1+…)

CMB CMB CMB

Pixel N-1fN-1

Pixel NfN

Pixel N+1fN+1

0.3K - 0.1K R C

RF mux• A KID has high transmission at f away from resonance.

This fact can naturally be used for multiplexing many detectors, tuned at different resonances f, all loading the same transmission line.

• Using excitation in the GHz range:

• high quality wireless components are available

• thousands of detectors can be multiplexed, with a single coax and a single HEMT

R C

Al resonators process (IRST-ITC)

Al resonators (IRST-ITC)

La Sapienza: Measurement Testbed

5-10 GHz

0.3K

Pulse Tube Refrigerator and 3He/4He fridge

Directional DetectorKrytar 1820

Detector Krytar 201

Front-End devices Made in Italy

• Corrugated feed horn at 44 GHz

• Designed, made (by electro-erosion on aluminum) and tested in Italy

•Milano Group (Bersanelli, Mennella et al.)

• Corrugated feed horn at 44 GHz

• Designed, made (by electro-erosion on aluminum) and tested in Italy

•Milano Group (Bersanelli, Mennella et al.)

Riccardo Tascone et al.:Five-Level Waveguide

Correlation Unit (European Patent, 05019553.6)

Ka band

Impressive

Performance:

,

V

IK

U

QH

U

Q

m

m

Figure 4. Spectral distribution of the elements of K

.

Figure 3. Spectral distribution of the elements of H

.

R. Tascone et al.

OMTfor Ka band

28 30 32 34 36-60

-50

-40

-30

-20

-10

0

S33

(meas) S

33 (simul.)

S44

(meas.) S

44 (simul.)

mag

nitu

de [d

B]

f [GHz]

28 30 32 34 36-80

-70

-60

-50

-40

isolation S21

cross-coupling S41

cross-coupling S32

mag

nitu

de [d

B]

f [GHz]

Return Loss at each of the four ports > 30 dB;

Isolation of 70 dB;Cross-couplings of -65 dB;

Group Delay equalization within ± 5 ps;

Insertion Loss < 0.1÷0.2 dB.

• Can all this be extended to higher frequencies, keeping the same performance ?

• Under study.

Cryogenics Made in Italy:

devices and cryostats

FETBOX

CQM

on

Planck

FETBOX Flight Model

The JFET BOX: 72 diff. Channels, < 200mW @ 50K, 5 nV/sqrt(Hz)

130K50K

50K

130K50K

50K

D. Brienza et al., “Cryogenic Preamplifiers for high resistance bolometers”, WOLTE-7 - ESA-WPP-264, pg. 283-288, (2006).

Sun Shield

Ground Shield

Solar Array

Cryostat and

detectors

Primary Mirror

(1.3m)

Differential GPS Array

Star Camera

the BOOMERanG balloon-borne telescope

B03 Sensitive at 145, 245, 345 GHz

S. Masi et al. Cryogenics, 39, 217-224, 1999

The The FridgeFridgeCryopumpIt works with charcoal carbon grains

It adsorbs when T < 12 K (mechanical thermal switch)

It desorbs when T > 20 K (heater)

Condensation pointThermally connected to the 4He bath with 2 gold plated high purity copper rods

Pumping tubesThin wall stainless steel tubes

Liquid 3He evaporatorT = 0.280 K

Volume = 130 cm3

34 STP liters of 3He gas

Holding time: 14 days

S. Masi et al. Cryogenics, 38, 319-324, 1998

ASI-OLIMPOCryostat for 130 bolometric detectors (both TESs and Semiconductors)

• PILOT - CNES

Cryostat for large bolometer arrays (1024@240m + 1024@550m)Main challanges: • Radiation shields • Thermalization of bolo cables• Weight & Size

Industrial support for Cryogenics

• In Italy:

– Alenia– CECOM– Galileo Avionica– LMP– RIAL– ….

Calibration DevicesMade in Italy

S. Masi et al. 2006, A&A, 458, 687-716 , astro-ph/0507509

The “Paolorizer” for BOOMERanG-B03

XPol<1x10-3

• We also had a calibration lamp in the Lyot stop of BOOMERanG and..

• … surprise surprise, it is polarized !

Cal Lamp

The LFI calibrationThe LFI calibration

BB calibrator

LFI cold loads

RCA AIV (2/2)RCA AIV (2/2)

Inputs for discussion(from recent Italian brain-storming)

• Scientific Objectives:– E–modes free from systematic effects– B– modes at the best we can do– lmax = ~ 500 for distinguish primordial B mode from lensing B

mode– Precise polarized foreground maps (~ 0.1 uK) for systematics and

astrophysics

• 1st Level Requirements:– L2 orbit (for systematic effects)– Frequency Coverage: 20 GHz to 500 GHz would be ideal for

accurate cleaning of the various classes of foregrounds and astrophysical studies. Low end difficult due to telescope size.Feasibility of a strictly linked ground based program ?

– Sky coverage: Full sky– Detector Technology: different technologies exist. It would be

good to crosscheck systematics with at least one frequency band with different technology

– Polarimetry needed

• 2nd Level Requirements– Sensitivity: < 0.1 mK * sec^(-1/2). See note (*)– FWHM: depends on science. See note (**)– Lifetime: 4 full sky surveys 2 years– Number of detectors: few 103 / frequency. See note (***)– Technology: HEMT from 20 to 100; Bolometers from 70 to 500 GHz. – Cryogenics: Depending on the detectors used (type, number,

dissipation) and mission requirements (lifetime, spacecraft size etc.), the mission cryo chain could be a combination of the following possible systems:

• From 300K to ~50K, ~3 passive radiators (V-Grooves?) in L2; or their combination with active coolers, mechanical (low vibration) or sorption, to reduce number/dimensions of passive stages

• Below ~50K – sorption/JT cooler with H2 or Ne + sorption/JT He – mechanical cooler (pulse tube, vibration level?)– Liquid/solid cryogens

• From ~5K to 0.1K, – dilution cooler– ADR

– OMT based architecture for high purity polarization measurements.

Frequency (GHz)

lmax Required Diameter (meter)

20

500 3.5

1000 6.5

1500 10

100

500 0.7

1000 1.3

1500 2.0

500

500 0.1

1000 0.3

1500 0.4

30 dB taper

Separate telescopes for different bands ?

• Appealing option because– It allows to mazimize the size of polarization-pure focal

planes– It reduces integration complexity

• If on two separate satellites: easier optimization of scan strategy (4 Planck satellites can be fitted inside the ARIANE V) .

• Moving bands to GND and Balloons will help with budget !