Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

150Nd Project

• Nd crystals used so far

• News about NdGaO3

• Scintillating Bolometers

• Conclusions & Prospect

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

Two Crystal compounds

NdGaO3 Good “theoretical” candidate 16 g sample200 g sample

The small sample was tested at sea level @ Milano-Bicocca and Firenze

The big sample was tested deep underground @ LNGS

Compound Density [g/cm3]

Melting Point [Cº]

Deby Temp. [K]

Nd Fraction [%mass]

NdF3 6.51 1377 n.a. 71

NdGaO3 7.57 1605 676 55

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

NdGaO3 Milano-Bicocca Test

Paramagnetic heat capacitance

Final temperature 38.5 mK

1.3x1.3x1.3 cm3

PTFE supports

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

NdGaO3 Firenze Test

The main difference was in the choice of the thermal conductance between crystal and Cryostat. The choice was a hard contact in order to cool down the crystal to lowertemperatures with respect the ones reached in Milano.

Nylon wires

1.5 cm2 thermalization surface Cu-NdGaO3

Mixing chamber Temperature: 20 mK

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

NdGaO3 LNGS Test

3x3x3 cm3

PTFE supports (low conductance)

Two different set-up were used

Low conductance set-up

High conductance set-up

200 g

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

NdGaO3 LNGS

After 10 days the temperature reached was ~34 mK

After 70 days the temperature reached is ~16 mK

We see thermal pulses, but some Serious doubts arise on the identification of actual particle pulses

Injected thermal energy of ~ 1300 keV

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

New Run Hall C

We mounted the small NdGaO3 Crystal. The aim is to see if,, due to the smaller mass, we are Able to recognize actual particle pulses.

The run started Friday 8 April. The temperature is slowly decreasing and is now around 30 mK.

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

Innovative Techniques

Several tests were made in the R&D cryostat @LNGS during the lasts months

The idea is to move towards a active background rejection

Double readout heat - light

Nuclei with Q-Value above the 208Tl - line

100Mo 3034 keV

48Ca 4271 keV

116Cd 2802 keV

We developed suitable bolometric light detectors with a Energy resolution of 3050 eV

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

Light detector

PbMoO4

CaMoO4SrMoO4

MgMoO4

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

Large-Surface Light detector

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

PbWO4

Scatter Plots

CaMoO4

SrMoO4

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

First “LARGE” mass high RESOLUTION scintillating bolometer for DBD

150 g of CdWO4

Stefano Pirro, IDEA Meeting -Orsay April 14 , 2005

Conclusions

• Neodimuim-based Detectors/Bolometers shows clearly the difficulties of this compound

• There is, nevertheless, some hope to have some new results

• The use of the enriched Nd is, in my opinion, one of the last chance

• The “new” implementation of scintillating bolometers clearly shows the easy feasibility of a “new” powerful experiment

• Lot of effort is needed in order to identify a suitable scintillating compound