MANU2: status report 2004-05

Maria Ribeiro Gomes*

for the

Genoa Group

IAP, 14-Nov-05 * pos-doc under TRN HPRN-CT-2002-00322

Objectives

• Micro-calorimetric neutrino mass direct measurement• Investigate Re-187 beta decay @ 1 eV/c2 region

Requirements

• Stable TES sensors (Ir-Au or Al-Ag)• Required energy resolution 5-10 eV FWHM @ 6 keV• no-SQUID readout electronics• 300 calorimeters with Re single crystal absorber

Second generation experiment

IAP, 14-Nov-05

TES R&D

-Stable SC intermetallic alloy(instead of bilayer)

-SC -phase from phase diagram

IAP, 14-Nov-05

Al-Ag alloyX-ray diffraction pattern from film growthby e-beam evaporation of Al and Ag onto Si(110) substrate

TC of the alloy depends on the material stoichoimetry: 80 -120 mK

Advantages:Easy preparationFreedom on TC choiceShorter pulse

TES R&D (cont.)

Ir-Au

multilayer

•Stable/reproducible performance

•PLD on Si substrate and subsequently patterned by ion sputtering

Ir-Au-Ir on Si

Photo-resist pattern

Ar ion-etching

Final result

Pulsed Laser Deposition• Laser frequency: 2-10 Hz• Starting pressure: 6.5 × 10−9 mbar• Plasma pressure: 1.2 × 10−7 mbar• Substrate temperature: 350 oC• Laser energy: 500 mJ/pulse• Ablation rate: 0.1 – 0.4 Å/shot

IAP, 14-Nov-05

balance

Linear sample feed-through

laser

Au target

Sample holder

Si substrate wafer

Laser beam Nd:YAG1064 nm

Plasma plume

Target carrousel

Ir target

S-N phase transition

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

82,5 82,6 82,7 82,8 82,9 83 83,1 83,2 83,3 83,4 83,5 83,6 83,7 83,8 83,9 84

T(mK)

R(mohm)

i=0.4mA

R=200 m @ 82.9 mK

=T/R (R/T) ~ 9100

Ir-Au

TES

IAP, 14-Nov-05

Detector performance comparison

Calorimeter

Sensor

c#18

Ge-NTD

c#28 c#31 c#35 c#55

Ir-Au TES

Re (g) 60 1520 310 210 215

CRe (pJ/K) 0.11 3.3 0.75 0.5 0.5

Csensor (pJ/K) 3.6 3.6 1.8 1.8 0.02

Rsensor () 4.9M 6.0M 7.8M 6.6M 1

Vnoise (mV) cal. 4.1 4.5 5.2 4.7 -

Baseline noise (mV)

4.5(.2) 4.0 5.4(.2) 4.6(.2) 650 pA

E(eV) cal.FWHM@5.9 keV 28.2 82.3 44.7 33 5.8

E(eV) meas.FWHM@5.9 keV 30.6 77.6 44.7 37.6 11

IAP, 14-Nov-05

Transformer readout electronics

• Trans-resistance amplifier coupled via transformer• Low temperature operating transformer (100 mK)• Transformer core material selected over: -metal, ferrite,

metallic amorphous, spin glasses• Low noise RT JFET amplifier: present noise 0.9 nV/√Hz

• Integrating stage in order to flat the transfer function

IAP, 14-Nov-05

5pf270pf

1K Rb=1

0.01

5H3.6H ∫

1.6

Cold transformer and bias circuit

•Measured noise:14 pA/√Hz @ 1 kHz, < 20 pA/√Hz @ 0.5-5 kHz

•There is space of parameters for optimal matching:

• I(thermal noise)=√ (4kT2aI/Geq) ~ T √ (4k) √(a/R)

• Signal to noise is proportional to √R• Setting a proper value of the TES

resistance it possible move the current equivalent thermal noise to level in the range of the current equivalent electronics input noise

a=2500-5000 K-1, R=1W-> I(thermal noise) ~ 30-50 pA/√Hz

Further improvement can be done with new JFET (0.3 nV/Further improvement can be done with new JFET (0.3 nV/√Hz, 10 Hz, 10 fA/fA/√Hz) and a slight higher mutual inductance transformerHz) and a slight higher mutual inductance transformerIAP, 14-Nov-05

-40

-20

0

20

40

60

80

1.0E+1 1.0E+2 1.0E+3 1.0E+4 1.0E+5

Input Current

transformer Vout

Integrated Output

Transfer function

IAP, 14-Nov-05-40

-20

0

20

40

60

80

10 100 1000 10000 100000

Single pixel results

• Ir-Au TES on high-purity Si substrate @ 70 mK• Re crystal absorber with (400x470x54) m3 0.2 decay/s• Tested bandwidth (1-1000) Hz and readout by DC-SQUID

pulse-height=2560 mV

rise time 160 s

pileup discrimination time 80 s

RMS noise 1.2 mV

Energy resolution at 6 keV

IAP, 14-Nov-05

Statistical Sensitivity

IAP, 14-Nov-05

MANU

MANU2

Under progress…

•testing 1 single disc: 20 readout channels

16 mg 3 months 1.2 x 108 counts

200 channels in measurement by Mars 2006

In 1 yr of data taking 9x109 counts

(MANU: single 1.5 mg Re crystal, Ge-NTD sensor and 3 months 7x106 counts )

•Number of channels ~ 300

•Total Re mass ~ 250 mg

•Expected count-rate ~ 300 counts/s

•Expected sensitivity between 1.5 and 1.7 eV

IAP, 14-Nov-05

18 m/disc10 discs 180