1. 1 Particle interaction with resonant detectors:
the cosmic ray detection and the RAP experiment
G. Modestino
INFN - Laboratori Nazionali di Frascati
P. Astone, M. Bassan, P. Bonifazi, B. Buonomo, G. Cavallari, E. Coccia, S. D’Antonio, V. Fafone,
G. Giordano, C. Ligi, A. Marini, G. Mazzitelli, Y. Minenkov, I. Modena, G. Modestino, A. Moleti,
GV. Pallottino, G. Pizzella, L. Quintieri, A. Rocchi, F. Ronga, R. Terenzi, P. Valente, M. Visco.
INFN – LNF, LNGS, Roma 1, Roma 2
Università di Roma La Sapienza
Università di Roma Tor Vergata
INAF (Istituto di Fisica dello Spazio Interplanetario)
CERN Geneva
G Modestino, ET-ILIAS_GW, Nov 2008 1
G Modestino, ET-ILIAS_GW, Nov 2008

2. Particle interaction with resonant detectors:
the cosmic ray detection and RAP experiment
RAP experiment. (Rivelazione Acustica di Particelle)
Study about NAUTILUS anomaly
The thermo-acoustic model at low temperature.
The discontinuous behavior passing through the critical temperature.
The cryogenic resonant GW detectors NAUTILUS (Frascati) and EXPLORER (CERN) The cosmic ray detectors. The expected rate.
The interaction of the cosmic rays with the aluminum bar and the thermo-acoustic model. The large statistical sample at low temperature.
Full agreement with the model and with RAP results.
G Modestino, ET-ILIAS_GW, Nov 2008

3. The unexpected result …
NAUTILUS K
The unexpected result …
…induced to proceed to a dedicated experiment
RAP (Rivelazione Acustica di Particelle)
and in the meantime to implement EXPLORER with a cosmic ray detector.
G Modestino, ET-ILIAS_GW, Nov 2008

4. G Modestino, ET-ILIAS_GW, Nov 2008

5. The thermo-acoustic model
The excitation energy E of the fundamental vibration mode of the aluminum cylinder
L = bar length
R = bar radius
lo = length of the particle track inside the bar,
Zo = distance of the track mid point (from one end of the bar)
Θo = angle between the particle track and the axis of the bar
dW/dx = energy loss of the particle in the bar
ρ = density
v = longitudinal sound velocity in the material (for a thin bar)
g = Gruneisen parameter.
G Modestino, ET-ILIAS_GW, Nov 2008

6. The First Longitudinal Mode Oscillation X(T)
and the Gruneisen factor g
Thermo Acoustic Model
in the normal conducting state
Thermo Acoustic Model
in the superconducting state
Two possible hypotheses:
A. M. Grassi Strini, G. Strini, G. Tagliaferri (1980)
*Extension of thermo-acoustic model
using g of the material in the SC state
(no local SC-N transition induced)
**The beam induces a SC-N transition
in the material.
Two terms : normal thermo-acoustical
parameters + SC-N transition pressure wave
A.M. Allega & N. Cabibbo, (1983)
A. De Rujula & B. Lautroup (1984)
G Modestino, ET-ILIAS_GW, Nov 2008

7. Al 5056 results in the normal state
AstroParticle Phys 24, 65 (2005)
T=264K m=
Xmeas/W = m/J
in agreement with the thermo-acoustic model in a vast range of temperature
T=71K m=
Measured maximum amplitude [10 −16m]
Xmeas/W = m/J
T=4.5K m=
Xmeas/W = m/J
Theoretical amplitude value [10 −16m]

8. NIOBIUM results in the normal state
Europhys. Lett 76, 987 (2006)
G Modestino, ET-ILIAS_GW, Nov 2008

9. NIOBIUM results in the SC state
Europhys. Lett. 76, 987 (2006) * * *
G Modestino, ET-ILIAS_GW, Nov 2008

10. Extending the measurement to the Al5056 superconducting state
In progress
Enhancements of NAUTILUS response in the SC state
CONFIRMED
@ T>0.9K
Xmeas/W= m/J
Full agreement with the model and previous measurements
|X| / W *10-12 (m/J)
@T<0.9K
Released energy dependence !!!
G Modestino, ET-ILIAS_GW, Nov 2008

11. Al5056 superconducting state
In progress
Average values of the normalized vibration amplitude X/W vs the average energy released per beam pulse
Temperature range
0.57≤T≤0.63K
The line is the best fit given by
<X/W>=(95.5 ± 1.2)10−11 e (−32.8±7.5)<W > m/J.
G Modestino, ET-ILIAS_GW, Nov 2008

12. Al 5056 specific heat
Measurements based on calorimetry
Measurements using the temperature increments(T) due to beam hits
0.63K<T<.65K
T(K)
G Modestino, ET-ILIAS_GW, Nv 2008

13. The cosmic ray detector
NAUTILUS
LNF-FRASCATI
Above the cryostat:
3 layers of 24 streamer tubes each
Total area 36 m2
Bar Al 5056
M = 2270 kg
L = 2.91 m
Ø = 0.6 m
Below the cryostat:
4 layers of 11 streamer tubes each
Total area 16.5 m2
Calibration by muon charge
Particle density saturation~ 1000 part/m2
GPS clock synchronization
(with NAUTILUS DAQ)
G Modestino, ET-ILIAS_GW, Nov 2008

14. The cosmic ray detector
EXPLORER
CERN-GENEVA
Above the cryostat:
Single layer of 11 scintillators
Total area 9.9 m2
Bar Al 5056
M = 2270 kg
L = 2.97 m
Ø = 0.6 m
Below the cryostat:
Double layer of 4 counters
Total area 6.3 m2
Calibration by muon charge
Particle density saturation~ 2000 part/m2
GPS clock synchronization
(with EXPLORER DAQ)
G Modestino, ET-ILIAS_GW, Nov 2008

15. The integral rate of the extensive air shower events (EAS).
Prevision (by G. Cocconi formula *) and measurements
* H (≥L) = kL-l events/day
Λ= the density of secondaries in an EAS
number of charged particles per m2
λ= ln(Λ)
k=3.54 ×104
*(at sea level and in absence of absorbing material)
G Modestino, ET-ILIAS_GW, Nov 2008

16. { n=1.15 for normal Al5056 s=3.7 for superconducting Al5056 16 [K]
The expected energy amplitude
NAUTILUS - EXPLORER response
if the particle energy W (in GeV units) is released in the bar center
[K] {
n=1.15 for normal Al5056
RAP
s=3.7 for superconducting Al5056
G Modestino, ET-ILIAS_GW, Nov 2008
G Modestino, ET-ILIAS_GW, Nov 2008 16

17. EXPLORER NAUTILUS T≥TC
The integral event rate measurements and comparison with the expected rate
EXPLORER NAUTILUS T≥TC
Astroparticle Physics, 30,200,(2008)
G Modestino, ET-ILIAS_GW, Nov 2008

18. Superconductive NAUTILUS
Astroparticle Physics, 30,200,(2008)
G Modestino, ET-ILIAS_GW, Nov 2008

19. Superconducting and normal AL comparison
Averages of signals with energy ≤ 0.1 K, grouping data in ranges of particle density Λ.
2003, 2004, 2005, 2006 (open circles) NAUTILUS at T = 3 K 2003, 2004, 2005, 2006 (filled squares) EXPLORER at T = 3 K
Astroparticle Physics, 30,200,2008
G Modestino, ET-ILIAS_GW, Nov 2008

20. Summarizing
RAP results provide the key to interpret the discrepancy in the
cosmic ray rate, for NAUTILUS in the superconductive state.
Therefore no anomaly found in the CR interaction or composition
However, the behavior of superconductive aluminum need further studies especially by investigating at T<<Tc.
G Modestino, ET-ILIAS_GW, Nov 2008