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Journal of Radioanalytical and
Nuclear Chemistry
An International Journal Dealing with
All Aspects and Applications of Nuclear
Chemistry
ISSN 0236-5731
Volume 304
Number 2
J Radioanal Nucl Chem (2015)
304:955-963
DOI 10.1007/s10967-014-3341-5
Atomic and isotopic changes induced by
ultrasounds in iron
Gianni Albertini, Fabio Cardone,
Monica Lammardo, Andrea Petrucci,
Filippo Ridolfi, Alberto Rosada, Valter
Sala & Emilio Santoro
1 23
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Atomic and isotopic changes induced by ultrasounds in iron
Gianni Albertini •Fabio Cardone •Monica Lammardo •
Andrea Petrucci •Filippo Ridolfi •Alberto Rosada •
Valter Sala •Emilio Santoro
Received: 26 March 2014 / Published online: 27 July 2014
ÓAkade
´miai Kiado
´, Budapest, Hungary 2014
Abstract Electron microscopy and neutron activation
techniques are used to map the elemental and isotopical
compositions of ferrite bars where the emission of neutron
bursts and the formation of dark regions were reported after
ultrasound irradiation. Anomalous values are found in
these regions. The original concentrations of natural iso-
topes of copper and zinc are deduced; the occurrence of
pressure-induced nuclear reactions is inferred while the
cavities are suggested to act as nuclear micro-reactors. The
general characteristics of these phenomena are considered
a support to the existence of a new type of reactions, called
deformed space–time reactions (DST-reactions).
Keywords X-ray energy dispersive system analysis
Envinronmental scanning electon microscopy Isotope
determination Neutron activation analysis Ultrasounds
Piezonuclear reactions Cu-Isotopes Beta decay
Introduction
Pressure, either by ultrasound irradiation or by using
industrial presses, has been reported to produce emission of
nuclear particles [1–13]. These results are not easy to
explain at the light of the scientific knowledge and tech-
nological experience so far commonly acquired, as the
average density of the transferred energy (e.g., 0.1 MeV
G. Albertini
Dipartimento di Scienze e Ingegneria della Materia
dell’Ambiente ed Urbanistica (SIMAU), Universita
`Politecnica
delle Marche (UNIVPM), Via Brecce Bianche, 60131 Ancona,
Italy
G. Albertini (&)
CNISM (Consorzio Nazionale Interuniversitario per le Scienze
fisiche della Materia), Ancona Unit, Ancona, Italy
e-mail: albertdom@vodafone.it; g.albertini@univpm.it
F. Cardone
Istituto per lo Studio dei Materiali Nanostrutturati (ISMN–CNR),
Via dei Taurini, 00185 Rome, Italy
F. Cardone A. Petrucci
GNFM, Istituto Nazionale di Alta Matematica ‘‘F.Severi’’,
Citta
`Universitaria, P.le A.Moro 2, 00185 Rome, Italy
M. Lammardo E. Santoro
Unita
`Tecnica Tecnologie e Impianti per la Fissione e la
Gestione del Materiale Nucleare (UTFISST), Laboratorio
Reattori Nucleari (REANUC), Ente Nazionale Energia e
Ambiente (ENEA), Via Anguillarese, 301, 00123 Rome, Italy
A. Petrucci
Ente Nazionale Energia e Ambiente (ENEA), Via Anguillarese,
301, 00123 Rome, Italy
A. Petrucci
CNR-ISMN National Research Council of Italy, Via dei Taurini,
00185 Rome, Italy
F. Ridolfi
Dipartimento di Scienze della Terra, della Vita e dell’Ambiente
(DISTEVA), Universita
`degli Studi di Urbino ‘‘Carlo Bo’’
(UNIURB), Campus Scientifico ‘‘Enrico Mattei’’ Via Ca
`Le
Suore 2, 61029 Urbino, Italy
A. Rosada
Unita
`Tecnica Tecnologie e Impianti per la Fissione e la
Gestione del Materiale Nucleare (UTFISST), Laboratorio
Caratterizzazione Materiali Nucleari (CATNUC), Ente
Nazionale Energia e Ambiente (ENEA), Via Anguillarese, 301,
00123 Rome, Italy
V. Sala
STARTEC ULTRASUONI Ltd Research Lab, Via Libero
Grassi, 1, 23875 Osnago, Lecco, Italy
123
J Radioanal Nucl Chem (2015) 304:955–963
DOI 10.1007/s10967-014-3341-5
Author's personal copy
per atom of iron) is many orders of magnitude lower than
those used in nuclear reactors (e.g. some MeV for light
nuclei, up to hundreds of MeV or some GeV for medium
weight nuclei like iron).
A possible explanation, however, was found in the case
of ultrasounds applied to aqueous solutions [14,15]. In that
case, in fact, the phenomenon of cavitation can take place
and the bubble implosion is accompanied by a shock wave
able to concentrate the energy that was deposited in the
bubble surface region, into a volume of atomic dimensions.
That abrupt energy concentration was evaluated and it was
considered sufficient to trigger nuclear reactions.
By following that opened way, a parallel phenomenon
was suggested to occur in solid matrices [16,17]. In par-
ticular in the case of Iron irradiated by ultrasounds, the
micrometric cavities already existing inside the sample
were proposed to play the same role as the bubbles inside
the liquid: the (locally isotropic) pressure induced by the
ultrasonic frontwave and the consequent implosion of the
gases included in the cavities can create an effect similar to
that proposed in the bubbles. Thus, also in this case, an
abrupt energy concentration able to trigger nuclear reac-
tions can be attained.
In both cases, either bubbles in aqueous solutions or
cavities in a solid sample (the ‘‘Ridolfi cavities’’), the
process can replicate. In the former environment, in fact,
new bubbles are formed during the cavitation process; in
the latter case, conversely, the same cavity can be filled
many times by molecules diffusing inside the material.
The emitted particles so far detected are claimed to be
neutrons and alpha particles [1–13]. However, concomitant
gamma ray emission, as it is expected in the known fission
reactions, was not observed. This absence was assumed as
the mark of a new kind of reactions, which were at first
defined ‘‘piezo-nuclear’’. The energy of the gamma ray is
assumed to be absorbed to deform the space–time, thus
resulting in particle emissions without gamma emission.
‘‘deformed space–time reactions’’ (DST-reactions) is a
more general name to indicate the piezo-nuclear ones and
also other reactions, which can occur without press or ul-
trasounds and do not imply emissions from the atomic
nuclei [18].
One of the most important consequences of obtaining
the nuclide emissions is that transmutations, i.e. the
transformations of elements into other elements, could be
obtained at relatively low energy [19].
In view of this technological application and also to
support the claimed emission of neutrons from sonicated
Iron bars, elemental analysis [16,17] and isotopic analysis
[20,21] of the sonicated iron bar were conducted
separately.
Aim of this paper is to make a comparison between the
results obtained from the two techniques, in order to
discuss if they can constitute a mutual verification and they
together can support the occurrence of transmutation
phenomena.
The samples
Two 10 cm long ferrite cylindrical bars (in the following
indicated as rod #1 and rod #2) with 2 cm diameter were
separately treated with 20 kHz ultrasounds in 2009 [10]at
the laboratories of Startec Ltd using the ultrasonic machine
R-1-S, assembled and patented by Startec Ltd. [22]. The
application of longitudinal ultrasonic waves, propagating
along opposite directions, resulted in the emission of
neutron bursts. A further effect was the formation of sev-
eral roughly circular and dark regions with diameters of
about a millimetre on the bar surface.
Beside the ferrite bars, which are considered in this
paper, some steel bars of the same shape were subjected to
the ultrasound treatment. Also in that case, neutron emis-
sions were detected and larger spots (with diameter of
about 3 mm) appeared on the surface: preliminary X-ray
atomic microanalysis put in evidence that different com-
positions characterise the dark damaged zones and the
apparently not damaged ones [10].
In our case, in order to investigate also the internal zones
of the two ferrite bars, two samples were cut from each of
them (Fig. 1).
The samples are parallelepipeds with heights corre-
sponding to the bar diameters. The two basis, with area S
*4mm
2
, are lightly curved, as they correspond to portions
of the lateral surface of the cylindrical bar.
In one sample from each rod (sample A from rod #1 and
sample C from rod #2), one base corresponds to a damaged
surface region while the other to an apparently not dam-
aged one.
In the other two samples (sample B from rod #1 and
sample D from rod #2) both the bases correspond to
apparently not-damaged surface regions. Inside each rod,
the two samples correspond to two parallel cuts. They were
extracted by using a wire-EDM (electric discharge
machining) device, belonging to Startec Ltd.
The elemental composition of samples A and B was
analised by environmental scanning electron microscopy
(ESEM) techniques, while the isotopic composition of
samples C and D by neutron activation analysis (NAA).
Elemental analysis by ESEM
After analysing the surfaces of samples A and B, one
among the longest faces of each of the two parallelepipeds
was polished down to the main central axis of the sample.
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Sand paper and diamond paste of various grit sizes (9, 6, 3,
1lm) were used. The polished surfaces were immediately
(B10 s) cleaned with water and 90 % ethyl alcohol and
dried using compressed air. The polishing, cleaning and
drying procedure took *10–15 min to complete. Addi-
tional information of the procedure can be found in [16].
A preliminary characterization of the samples by optical
microscopy, was followed by ESEM analysis using a FEI
Quanta 200 of UNIURB. The instrument is equipped with a
field emission gun, secondary electron (SE) and back
scattered electron (BSE) detectors, and an energy disper-
sive system (EDS) for X-ray atomic analysis. The operat-
ing conditions were a vacuum of 5.0 910
-6
m bar,
accelerating voltage of 30 kV and beam current of
264 mA. All the in situ X-ray analyses were performed
with a counting time of 100 s and maintaining a working
distance of 9.7 mm. This setting allows identifying almost
all the natural elements of the periodic table (from B to U).
The best SE and BSE image resolutions are 3.0 and 4.0 nm
respectively. The qualitative results obtained with the
ESEM–EDS were counterchecked using a FESEM ZEISS
SUPRA 40 at UNIVPM.
In order to obtain semi-quantitative data from ESEM–
EDS at UNIRB and to avoid artifacts coming from escape
peaks, sum peaks or peak overlaps, the results obtained
from the analytical software were corrected as it is reported
in Ref. [17].
Optical microscope and SE observations show that the
damage mark on the ferrite surface is irregular in shape and
well distinguishable from oxidized (rust) patches and the
drawn, intact surface of the ferrite bar. (The rust patches were
not present at the time of the ultrasound treatment, in 2009).
BSE imaging shows a cratered surface of lower bright-
ness, corresponding to lower average atomic weight, in the
damage region with respect to the intact ferrite surface.
Bright remnants of the original ferrite surface can also be
found between the cratered zones, which are characterized
by irregular and cracked interiors composed of a material
with a lower mass.
From a cross-sectional view of the sample A, the dam-
age region with low-brightness material is not thicker than
1 micron. The deeper craters have depths up to 20 lm and,
together with the bright remnants of intact ferrite, suggest
that highly energetic micro-explosions occurred.
The internal structure of the bar is mostly uniform apart
from a zone of *0.5 mm
2
with a large number of micro-
cavities (*1,300 per mm
2
)at*0.3 mm from the external
damage mark. The largest of these cavities has a diameter
of *10 lm.
At higher magnifications the cavities appear highly
deformed with irregular contours and partially filled with
chaotic, amorphous material. This material cannot be the
remnant of the oil-based diamond pastes used in sample
preparation, as no diamond grains or blurring typical of
fatty materials were found under SE. In addition, this
material appears stable under the heating effect of the
focused electron beam.
In the sample B, neither the damage zones nor the areas
characterized by a high density of microcavities filled with
amorphous material were found on either the external
surface or the inner region. Occasional and smaller sized
(\5lm) empty cavities are present in the internal part.
Mg and Ca spinels and oldhamite (a CaS phase with
minor Mn, Mg and C contents) are visible in both samples
A and B. They are typical inclusions of Fe–C alloys [23].
These non-metallic phases are not abundant and do not
show evidence of any type of reaction. Usually they are
small (B2lm) sub-euhedral inclusions in the ferrite
matrix.
One elongate and irregular cavity (maximum dimension
*15 lm) hosting several small crystals of Mg–Ca spinel
[i.e., (Mg, Ca)Al
2
O
4
] is visible in sample A. Although
these small spinels are potentially surrounded by gas, no
evidence of micro-reaction was found.
Fig. 1 The two parallelepiped
samples extracted from the
ferrite rod #1. Their height
(h=20 mm) corresponds to the
diameter size of the cylinder.
One base of the sample A
corresponds to a damaged
region
J Radioanal Nucl Chem (2015) 304:955–963 957
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The EDS analyses of the homogeneous intact ferrite
matrix, of the materials on the external damage mark and
inside the microcavities show that:
– The ferrite matrix is composed of iron with minor
amounts of carbon, chromium and manganese.
– The spectra of the damage mark show peaks of
elements not present in the intact ferrite such as
oxygen, sodium, aluminum, sulfur, chlorine, potassium,
calcium and copper, as well as a more pronounced
carbon peak.
– Carbon enrichment is particularly evident in the
formless material filling the microcavities, while lower
amounts of oxygen and sulfur are detected with respect
to the damage mark.
Semi-quantitative EDS data of the anomalous materials
on the surface and inside the bar are shown in Tables 1and
2together with the average composition of the intact fer-
rite, as it was obtained after analysing 12 external regions.
Several microanalyses of the chaotic, amorphous mate-
rial inside the microcavities (Table 2) had to be discarded
due to low X-ray intensity. The composition of the intact
ferrite is fairly homogeneous: besides iron (98.5 wt%),
small amounts of carbon (B0.1 wt%), chromium (0.4 wt%)
and manganese (1.0 wt %) were detected. The standard
deviations (r) indicate a high overall precision, the relative
error decreasing with the contents of the analyzed element,
from Carbon (21 %) to Iron (0.1 %).
– The low-brightness material in the external damage
zone shows variable compositions characterized by
lower Fe (83.4–90.0 wt%) and Mn (0.5–0.9 wt%)
contents and higher values of C (0.2–1.4 wt%) and Cr
(0.4–2.0 wt%,) than the intact ferrite.
– In addition, this damage mark material shows remark-
able and variable amounts of elements foreign to the
matrix of the intact ferrite such as Oxygen (O: 2.2–6.9
wt%), Chlorine (Cl: 1.5–2.9 wt%), Potassium (K:
0.9–1.4 wt%) and Copper (Cu: 0.7–3.8 wt%) as well
as smaller concentrations of Sodium, Silicon and Sulfur
(B0.6 wt%). Small amounts (B1.0 wt%) of Magne-
sium, Aluminum and Calcium are found only occa-
sionally (Table 1).
The X-ray microanalyses of the jagged material inside
the microcavities of the bar interiors show a lower number
of foreign elements (Table 2). Na, Mg, Cl, K and Cu are
apparently missing and the concentrations of Al, Si, S and
Ca are vanishingly small (B0.2 wt%). The contents of iron
(94.3–98.2 wt%) and oxygen (0.0–1.2 wt%) measured in
these small cavities are intermediate between those of the
damage mark and the intact ferrite but closer to the ferrite
composition.
The analyses of the microcavity material systematically
show higher C, Cr and Mn concentrations than the intact
ferrite (Table 2). The exsolution (i.e., remobilization in the
solid state) of these elements during the ultrasound treat-
ment appears to be rather improbable since the material
within the microcavities should have been associated with
Table 1 Composition of the intact ferrite matrix and of the surface
amorphous materials as deduced from Energy Dispersive System
(EDS) for x-ray analysis
Element Ferrite matrix
(12 points) (wt% ±r)
Amorphous
material in
the external
damage region
(wt%)
Number of
cases
(from 13)
Min. Max.
C 0.08 ±0.02 0.21 1.37 13
O 2.19 6.91 13
Na 0.08 0.24 13
Mg 0.01 0.20 3
Al 0.10 0.14 2
Si 0.07 0.36 12
S 0.25 0.59 13
a
Cl 1.48 2.86 13
K 0.87 1.38 13
Ca 0.22 0.99 6
Cr 0.43 ±0.05 0.41 2.04 13
Mn 0.97 ±0.08 0.48 0.91 13
Fe 98.52 ±0.11 83.43 90.05 13
Cu 0.75 3.84 13
a
In two cases the element was observed but its quantitative deter-
mination was not possible
Table 2 Composition of the intact ferrite matrix and of the amor-
phous materials inside the cavities as deduced from energy dispersive
system (EDS) for x-ray analysis
Element Ferrite matrix
(12 points)
(wt% ±r)
Amorphous material
inside the cavities (wt%)
Number
of cases
(from 7)
Min. Max.
C 0.08 ±0.02 0.25 2.93 7
O 0.33 1.20 6
Al 0.08 0.08 1
Si 0.07 0.21 6
S 0.08 0.14 2
Ca 0.18 0.18 1
Cr 0.43 ±0.05 0.47 1.00 7
Mn 0.97 ±0.08 1.02 1.43 7
Fe 98.52 ±0.11 94.29 98.15 7
958 J Radioanal Nucl Chem (2015) 304:955–963
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components poor in these elements and rich in Fe with
respect to the ferrite.
– From the structural characteristics and the composing
material of the damage mark, it could be produced after
a violent reactions within sub-surface zones, which
possibly led to the partial fusion of the ferrite and the
sudden fracturing and expulsion of the superficial
layers of the bar. This is supported by the presence of
bright remnants of pristine ferrite surface between the
cratered dark material and by the limited depth
(*20 lm) of the craters. In addition, the cracking of
the cratered material suggests that the material gener-
ated by the reaction was liquid, interacted with the
surrounding atmosphere and cooled rapidly.
Parts of the fused material were most likely expulsed
during the explosive phase, as suggested by its minimal
thickness in cross-sectional view. This is in agreement with
the presence of characteristic ferrite peaks (those of Fe, Cr,
Mn) in the EDS spectra of the damage mark. They suggest
that the ESEM electron beam had penetrated the entire
thickness of the damaged material and was interacting
primarily with the ferrite matrix.
– The irregular morphology of the material inside the
microcavities cannot be an artifact of the low resolution of
the ESEM because the FEI Quanta 200 is capable of
distinguishing objects having 3 nm sizes, at the operating
conditions used. The material inside the microcavities is
thus most probably composed of a chaotic assemblage of
sub-micron and likely amorphous particles.
The EDS spectra of the material in the microcavities, in
analogy with those from the damage mark, are composition
of X-rays originating from the materials within the mi-
crocavities (to a small degree) and those of the ferrite
matrix underneath (to a large degree). The material inside
the microcavities is predominantly composed of carbon.
– All of this indicates that the amount of material foreign
to the ferrite is minimal. This is supported by the
relatively high Fe contents in all the spot analyses of
the external damage mark (Table 1), which is in
contrast with the low BSE brightness of the material.
In fact, while the back-scattered electrons come from
material in the surface region, the emitted X-rays
derive from a bulb shaped volume extending deeper
into the sample: according to the Kanaya–Okayama
formula [24], in our case the beam penetration depth is
3.2 lm in ferrite and 9.9 lm in amorphous carbon.
Thus most of the measured X-rays came from the
ferrite lattice below the zones of interest.
The thickness of the materials should be larger in the
external damage mark than in the microcavitities, as the
detected Fe content in the former case is lower. The mass
foreing to the ferrite was evaluated to be 9–16 % in the
external mark and 0.4–4 % in the cavities.
– As the data of Tables 1and 2refer to the investigated
materials together with the underlying ferrite matrix, a
detailed analysis was performed in [17] plotting the
concentration of each element as a function of the
corresponding Iron concentration, as they were
obtained in the original data (Tables 1and 2only
report the minimum and maximum values).
The atomic changes observed after ultrasounds irradia-
tion can be summarized as follows:
– the material in the microcavities shows a systematic
increase in carbon (C), chromium (Cr) and manganese
(Mn), and decrease in iron (Fe) (Table 2);
– the surface damage zone shows a systematic increase in
carbon (C), oxygen (O), sulfur (S), chorine (Cl),
potassium (K), chromium (Cr) and copper (Cu), and
decrease in manganese (Mn) and iron (Fe) (Table 1).
The elements foreign to the ferrite bar are oxygen,
chlorine, potassium and copper.
The detected elements foreign to the ferrite (chlorine in
particular) are reasonably excluded to derive from either
inclusions common to Fe–C alloys or contamination during
wire drawing.
Isotope determination by neutron activation analysis
Compared to the EDS technique, that is able to analyse a
thin layer of surface material, the isotope determination by
neutron activation analysis (NAA) technique allows a
volumetric analysis for detecting elements even in minimal
amounts. In addition, different isotopes of the same ele-
ment can also be recognized.
In our case, the isotope analysis is of particular rele-
vance because of the observed emissions of nuclides. In
fact, the analysis of the isotopes is expected to give
important information of the nuclear reactions that can be
accepted or excluded as originating the emissions.
For many isotopes the NAA technique can detect masses
as small as 10
-12
g, thus allowing the study of elements
considered in trace or ultratrace.
On the other hand, NAA is not useful for light elements
like oxygen or carbon and gets low sensitivity for the
detection and analysis of other ones, like silicon, sulphur,
potassium or calcium.
The ability of NAA for analysing the whole volume can
be counterproductive in our case, as the zones of interest
occupy a very small fraction of the sample volume. In fact,
the mass investigated by EDS was *10
-8
g while that of
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NAA was *10
0
g, thus increasing eight orders of magni-
tude, mostly due to the contribution of the intact Ferrite
matrix. As a consequence, the concentrations of the ele-
ments of interest decreased almost of the same factor.
For the above reported reasons, the two techniques were
considered complementary and able to give mutual
support.
More details on the isotope determination by NAA
technique can be found in [25] and [26].
Before irradiating the two samples by neutrons, their
gamma spectrum was measured in order to check the
possible presence of gamma emitting radionuclides that
might be produced during the application of ultrasounds to
the bar. The measurements were carried out by a spec-
trometry system with a Canberra HPGe coaxial detector
having a resolution of 1.90 keV at 1,332.5 keV (Co-60), a
relative efficiency of 35 % and a peak to Compton ratio of
60.2–1. The system was connected to the high voltage
source (3,500 V?) SILENA model 7716. The detector was
connected to the amplifier SILENA 7611/L and to a multi-
channel Buffer Canberra Multiport II. The 8,192 channels
multichannel analyser works between 10 keV and 4 MeV.
The calibrations were carried out by the sources Cs-137,
Co-60 and Eu-152 of certified activity by CEA (Commis-
sariat a
`l’E
´nergie Atomique, France). The measurements,
their elaboration and the analysis of the spectra were car-
ried out by using the software Canberra Genie 2 K. In these
working conditions, which were defined by the manufac-
turer in the manuals, the efficiency of the apparatus is
constant between 1 and 4 MeV. The results from samples
C and D were thus compared with the environmental
background, each measurement lasting 100,000 s (live
time): no appreciable difference was found inside the
experimental incertitude.
The samples C and D were then neutron irradiated in
two steps at the TRIGA Mark II RC-1 reactor of ENEA
Research Centre in Casaccia (Rome, Italy):
– First step at the Pneumatic Transfer Tube (Rabbit): 60 s
with 1 MW power and flux of 1.25 10
13
ncm
-2
s
-1
,
corresponding to an accumulated fluence of 7.5
10
14
ncm
-2
– Second step, at the Rotating Rack (Lazy Susan): 6 h
with 1 MW power and flux of 2.6 10
12
ncm
-2
s
-1
,
corresponding to an accumulated fluence of 5.6
10
16
ncm
-2
.
In order to minimize the preponderant contribution from
Fe-59 and better detect the gamma irradiation from the
other radionuclides, different times and geometries were
used, as they are reported in Tables 3and 4.
A collimator was used to investigate the contributions
from three different parts of the samples: upper, central and
lower, the damage spot being located in the lower region of
sample C. To this aim a hole of 2.5 mm diameter was
drilled in a 2.5 cm thick piece of lead.
Each sample separately was first irradiated in the
pneumatic transfer tube, then holded 9 min after irradiation
in order to allow radioactivity to decay. After that decay
time, a 180 s measurement was performed. The collimator
was then used to investigate separately the lower, central
and upper parts of the sample.
After 3 h from irradiation, the whole sample was
investigated again and then the three separate parts. These
data are reported in the Table 3.
After irradiation of the two samples separately in the
Rotating Rack, the holding time was 4 days followed by
measurements of 1 h and then 20 days, followed by mea-
surements of 15 h for the whole sample and 22.5 h for each
Table 3 Geometry and times of the gamma spectrometry measure-
ments after irradiation in the pneumatic transfer tube (Rabbit)
Investigated
region
Lead
collimator
Decay
time
Measurement
time
Sample-
detector
distance
(cm)
Whole sample Not 903020
Lower Yes 1503020
Central Yes 2003020
Upper Yes 2503020
Whole sample Not 3 h 1.5 h 20
Lower Yes 4.5 h 1.5 h 20
Central Yes 6 h 1.5 h 20
Upper Yes 7.5 h 1.5 h 20
Table 4 Geometry and times of the gamma spectrometry measure-
ments after irradiation in the rotating rack (Lazy Susan)
Investigated
region
Lead
collimator
Decay time
(days)
Measurement
time (h)
Sample-
detector
distance
(cm)
Whole sample Not 4 1 10
Lower Yes 4 1 4
Central Yes 4 1 4
Upper Yes 4 1 4
Whole sample Not 20 15 10
Lower Yes 20 22.5 4
Central Yes 20 22.5 4
Upper Yes 20 22.5 4
960 J Radioanal Nucl Chem (2015) 304:955–963
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of its parts. These data are reported in the Table 4. From
the real measurement times the radioisotopes activity at
20 days was evaluated by considering their decay time.
A reference sample made of a certified SRM NIST 365
Electrolytic Iron was also irradiated in the Rotating Rack
and analysed in the same conditions as the investigated
samples, in order to calibrate the measurement process.
The NIST standard was weighted directly inside a Kartell
nuclear grade probe-holder with internal dimensions cor-
responding to those of the samples: 2 cm height and 0.2 cm
diameter. Its mass was 0.4155 g, those of samples C and D
were 0.5904 and 0.5765 g respectively. All the spectrom-
etry measurements were carried out, analysed and elabo-
rated by the counting system described above. More details
of the procedures can be found in Ref. [20].
While a detailed analysis of the behaviour of the dif-
ferent elements is left to a paper in preparation [21], here a
particular attention is given to copper. In fact, according to
the EDS–ESEM measurements this element is absent in the
matrix, while it is present in the amorphous material of the
external damage region (Table 1). In the amorphous
material inside the cavities, on the other hand, it was not
found (Table 2).
Concerning Cu isotopes, the most interesting results of
NAA are those obtained after treatment in the Rabbit, as
they are more suitable to detect radionuclides with shorter
half-life times (up to about 12 h).
In fact, the two natural isotopes of copper are Cu-63 ad
Cu-65. After neutron irradiation they produce the radio-
nuclides Cu-64 (with 12.7 h half life time) and Cu-66 (half
life: 5.1 min), respectively.
The Table 5reports the main information on these iso-
topes, the absolute errors also depending on the different
real times of measure of the different parts. It shows that
both the radio-isotopes got lower activity, which corre-
sponds to lower concentration of the corresponding natural
isotope, in the damaged sample C then in the reference
sample D.
If, however, the three parts of the samples are studied
separately, both the isotopes are more concentrated in the
zone close to the damage spot (lower part) with respect to
the reference, while the opposite part of the damaged
sample is poorer of they both.
A more accurate analysis of the same Table 5also
shows that the isotope Cu-65, which appeared in the central
and lower parts, strongly disappeared in the upper part
(480 kBq less in the upper part, to be compared with only
92 and 30 kBq more in the other two regions). The changes
of Cu-63, although following a similar trend, are more
balanced.
For the discussion to follow, it is also interesting to
consider the behaviour of Zinc, in particular present as Zn-
64, i.e. with the same atomic mass number of Cu-64.
The corresponding radio-isotope Zn-65 has half life of
244 days and was detected following the procedures of the
Rotating Rack.
As reported in Table 6, the whole damaged sample and
its single parts are richer of this element, the higher
increase being in the damage spot.
The Zn-69 radioisotope, corresponding to the natural
isotope Zn-68, is not considered as the experimental con-
ditions in some cases were not optimal for its detection
while in the other cases the differences between the values
in the damaged sample C and in reference sample D were
lower than the experimental error.
Discussion
The ultrasound irradiation of ferritic rods was reported to
induce neutron emission without concomitant gamma ray
radiation [10]. A further observed effect was the formation
of blackish and almost circular spots, 1 mm in diameter,
which were considered as damage zones produced on the
rod.
A campaign of measurements making use of different
techniques of electron microscopy put in evidence that
damage zones were different in composition and features
from the undamaged ones. Also a third zone, different from
these two, was recognized: in the internal region of the rod,
in correspondence of the external damage the observed
materials and the general featureas were different from the
previous two.
Particular attention is given in this paper to the occur-
rence of Copper atoms, which were detected in the amor-
phous material of the surface damaged zone (second zone)
Table 5 Copper radio-isotopes
Element Natural isotope Radio isotope cEnergy (keV) Sample C (damaged) versus sample D (reference)— activity difference (Bq)
Whole sample Upper part Central part Lower part
Copper Cu-63 Cu-64 1,346 -55.1 (±5.1) -11,200 (±1,600) -8,300 (±1,200) 13,900 (±2,600)
Copper Cu-65 Cu-66 1,039 -62,900 (±890) -479,000 (±50,000) 30,300 (±2,000) 92,100 (±3,900)
Difference between the activity in the damaged sample C and the reference sample D
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but not in the ferrite matrix (first zone) nor in the amor-
phous material inside the cavities of the internal parts under
the surface damaged zone (third zone).
Cavities containing amorphous materials were not
found, on the other hand, in the internal parts below the
undamaged surface.
The results of electron microscopy are here compared
with those from neutron activation analysis, which allows
studying different isotopes of a same element.
In accordance with the atomic analysis of EDS–ESEM,
copper isotopes were found with NAA techniques in the
damage zone. Thanks to the higher sensitivity of the iso-
topic analysis, the presence of copper in the matrix was
also detected. In fact, notwithstanding the intense signal
coming from the iron matrix, the adopted geometry and
times allowed to recognise the contribution of the copper-
64 and copper-66 radioisotopes, corresponding to natural
isotopes Cu-63 and Cu-65 activated by neutron irradiation
respectively.
The confirmed presence of copper is intriguing, as this
element is not a component of alpha iron. In the case that it
is present as an impurity, the greater effects are expected
from isotope 63, which has a natural abundance of 69 %,
rather then from isotope 65, with abundance 31 %.
In our case, on the contrary, isotope 63 is more abun-
dant: in fact, after considering the specific activity of the
two isotopes and their different decay times, the ratio Cu-
63/Cu-65 was evaluated to vary between 0.3 and 0.6 in
both samples, apart from the upper part of sample D where
the ratio is 1.7 ±0.2; in any case much lower than the
expected value 2.2 of the natural abundance.
We remark that gamma emission lines are in any case
well visible and measurable, also in Cu-64 at 1,346 keV,
that usually is not easy to detect due to the reduced yield
(0.49) and low efficiency of the detectors at that energy.
The large total mass of Copper in each sample (some
hundreds of micrograms, evaluated in a semi-quantitative
way) is of particular interest as no detectable amount of
Copper is expected in alpha Iron.
These results are a hint for considering the observed
changes not as a simple atomic diffusion inside the samples
due to the effect of ultrasound pressure but rather the
effects of nuclear reactions able to produce elements with
an isotopic ratio different from the ‘‘natural’’ one, in
accordance with the reported emission of neutron particles.
These emissions can be explained in the framework of the
‘‘Deformed Space Time’’ theory, as it was proposed and
widely discussed in Refs. [14] and [27].
Those nuclides could also be responsible for the
increased Zn-64 in the damaged sample (Table 6): a cap-
tured neutron transforms Cu-63 into Cu-64. This last
transforms into Zn-64 via beta-decay.
This chain of transformations could be either stimulated
by neutron irradiation during NAA treatments or by pi-
ezonuclear neutrons from ultrasonic irradiation. The
enhanced effect in the case of the damaged sample C,
however, is easier to explain if the latter hypothesis is
assumed.
Conclusions
The starting point of this paper was the effects of ultra-
sound irradiation on iron rods reported in ref.10: neutron
emissions were detected without concomitant gamma
radiation and also the formation of almost circular spots on
the surface was observed.
An elemental analysis by EDS–ESEM of one of the rods
put in evidence that at least three different types of regions
are formed: one is apparently unchanged ferrite; one cor-
responds to the damage spots and the third is the internal
region under the spots. Each region got different micro-
structural features and atomic composition, the last two
being characterised by the presence of amorphous material
and by the possible evidence of micro-explosions. How-
ever, the same amorphous material has different compo-
sition in these two regions. In particular, Copper was
detected in the amorphous material of the spot but not in
the amorphous material inside the underlying cavities.
The isotopic analysis by neutron activation confirmed
the presence of Copper, which is not a constitutive element
of Ferrite, and put in evidence that the Cu-63 and Cu-65
concentrations are different in the three types of regions.
Furthermore, the isotopic ratio is inverted in all cases: Cu-
63, more abundant in the natural ratio, is less abundant in
all the regions of the two sonicated samples, with respect to
Cu-65. All these facts taken into account, nuclear reactions
caused by sonication are supposed to occur, in accordance
to the deformed space time theory [14,27], which predicts
nuclear reactions induced by pressure.
Table 6 Zinc-65 radio-isotope
Difference between the activity
in the damaged sample C and
the reference sample D
Element Natural
isotope
Radio
isotope
cEnergy
(keV)
Sample C (damaged) versus sample D
(reference)—activity difference (Bq)
Whole
sample
Upper Central Lower
part part part
Zinc Zn-64 Zn-65 1,115 917 (±27) 85 (±1) 415 (±5) 466 (±5)
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A further hint for nuclear reactions and thus a support
for the reported neutron emission come from the Zn-64
distribution, as its concentration is higher in the damaged
regions, the highest value being in correspondence of the
damage spot. The isotope can be the final product of a
nuclear reaction involving a neutron and Cu-63, the latter
transforming into Cu-64 and then, after beta decay, into
Zn-64.
In conclusion, althought the sequence of the reactions is
not yet clarified, both the elemental and the isotopic ana-
lysis show that the zones where piezo-nuclear reactions are
suspected to occur have different Cu composition with
respect to the corresponding ferrite matrices, in both the
rods. In addition, the isotopical composition is different in
these two zones and is different from the natural ratio, all
these facts being a strong support to the hypothesis of
nuclear reactions induced by ultrasound pressure. These
reactions are proposed to be a consequence of a space–time
deformation, as discussed in Refs. [14] and [27].
The occurrence of piezo-nuclear reactions in these solid
materials was suggested in Refs. [16] and [17], where the
cavities with amorphous material are proposed to behave as
‘‘micro-reactors’’ (the ‘‘Ridolfi cavities’’), in analogy with
the micrometric bubbles in cavitated liquid materials.
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