Content uploaded by Francesco Celani
All content in this area was uploaded by Francesco Celani on Jul 30, 2020
Content may be subject to copyright.
J. Condensed Matter Nucl. Sci. 33 (2020) 1–28
Progress Toward an Understanding of LENR–AHE Effects
in Coated Constantan Wires in D2Atmosphere:
DC/AC Voltage Stimulation
Francesco Celani ⇤,†, C. Lorenzetti, G. Vassallo‡, E. Purchi, S. Fiorilla, S. Cupellini,
M. Nakamura, R. Burri, P. Boccanera, P. Cerreoni and A. Spallone§
International Society for Condensed Matter Nuclear Science (ISCMNS_L1), Via Cavour 26, 03013 Ferentino (FR), Italy
This paper presents a summary and some deeper details about the experiments presented at the 22nd International Conference
on Condensed Matter Nuclear Science (ICCF22). It reports on the experimental study of LENR phenomena in Constantan
(Cu55Ni44 Mn1)from its inception in 2011 to the most recent experiments. Using an empirical approach we identiﬁed the ef-
fect of surface modiﬁcation of the Constantan wires with coatings comprised of elements that enhance the absorption behavior,
and oxides with low work function for electron emission. We also explored certain geometrical arrangements of the wires such as
knots and coils in order to induce local thermal gradients and predictable hot-spots. Moreover, the DC polarization of the wires by
a counter-electrode proved to be a versatile approach to induce non-equilibrium conditions that are essential for Anomalous Heat
Effects (AHE), especially when a dielectric barrier discharge (DBD) is produced. From the review of experiments summarized in
this article, we obtain indications that the main parameter controlling the AHE is the ﬂux of reactive species through the surface
of the loaded material. As a consequence, all other external conditions of the reactor core (voltage–current, temperature, pressure,
electric ﬁeld stimulations, DC and/or AC external ﬁelds), can be seen as co-factors that enable a ﬂux of active species through
surfaces and in the bulk of the materials. Although most of the tests are in agreement with a possible ﬂux model, some results still
lack an interpretation, probably due to limits of the experimental setup.
2020 ISCMNS. All rights reserved. ISSN 2227-3123
Keywords: Anomalous Heat Excess (AHE), Cu–Ni–Mn alloy, Deuterium, Dielectric barrier discharges (DBD), Hydrogen, Low
work function coatings, Nickel–Copper alloys, Nickel hydrides and deuterides
⇤Corresponding author. E-mail: email@example.com.
†Also at: Ist. Naz. Fis. Nuc.-Lab. Naz. Frascati (INFN-LNF), Via E. Fermi 40, 00044 Frascati(RM), Italy.
‡Also at: DIIS, University of Palermo, 901298 Palermo (PA), Italy.
§Also at: Ist. Naz. Fis. Nuc.-Lab. Naz. Frascati (INFN-LNF), Via E. Fermi 40, 00044 Frascati(RM), Italy.
2020 ISCMNS. All rights reserved. ISSN 2227-3123
2F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Our group has studied Anomalous Heat Effects (AHE) in nickel–copper alloys for several years [1–10]. Apart from
some initial speculation  one of the motivations for the choice of these materials came from the work of Romanowski
 who showed their remarkable capability at promoting the dissociation of molecular hydrogen (H2). Moreover we
came across the work of Bruckner  who observed a reduction of electrical resistance of the alloys when exposed
to hydrogen as well as the pioneering experiments of Ahern with Ni–Cu multilayer structures .
Among various Ni–Cu alloys, Constantan (Cu55Ni44 Mn1)wires became in particular the focus of our studies
because of their low cost, versatility and robustness in various experimental setups. To sum up, Constantan resembles
palladium (which has been more extensively studied) in that both require loading with D2or H2, and conditions of
non-equilibrium to produce AHE.
Under certain conditions indeed, absorption and/or desorption, of D (or H), are associated with exothermic phe-
nomena exceeding by orders of magnitude the enthalpy of conventional chemical reactions.
Still, when non-equilibrium conditions are absent, AHE are either reduced or they tend to decline over time. This
observation led our group to investigate ways to increase non-equilibrium conditions through years of trial and error.
In a typical experiment, a 200 µm Constantan wire is oxidized by heating it in air with direct current or with a sequence
of short duration, low repetition rate pulses of high peak power. These repeated oxidations create a sub-micrometric
texture of oxides featuring a large surface area. The oxides are then easily reduced and the resulting porous layer
enables the quick absorption of D (or H). Signiﬁcant improvements in reproducibility and AHE magnitude were
made by modifying this porous layer with low work function oxides  comprised of strontium, potassium, iron, and
manganese. An SEM analysis of wires after treatment and reduction shows a sub-micrometric texture of heterogeneous
composition where areas rich in nickel and copper respectively can be easily distinguished, iron and manganese instead
appear in isolated islands whereas potassium and strontium oxides are uniformly distributed.
That being said, the experiments are conducted by direct constant-current heating of the wires in a D2atmosphere.
Typically they are allowed to saturate at a pressure of 2 bar for a few days at a temperature between 300 and 500C,
then the pressure is gradually reduced below 100 mbar. In general, AHE occurs if a series of conditions previously
reported [3,4] are met. AHE proves indeed to be correlated with the amount of absorbed deuterium as well as with
the presence of non-equilibrium conditions that we speculate promote a ﬂux  or migration of active species at the
interfaces of the spongy wire.
Initially, changes in pressure, temperature, voltage, current, and the arrangement of the wires showing thermal
gradients (i.e. hot spots), were introduced with a certain degree of success [6,12].
Quite interestingly the authors also found a remarkable empirical association among the thermionic emission of
the wires and the occurrence and intensity of AHE . Despite a lack of a clear mechanism, this peculiar correlation
quickly became the focus of much experimental work. This turned our attention to electric stimuli such as the intro-
duction of a voltage with a second wire acting as counter electrode, and even a low frequency alternating polarization
(50 Hz). Afterward, a new setup was designed to isolate and explicate the effects of the thermionic emission from
the hot wires and electric stimuli, hence in the most recent experiments, strong thermal gradients were avoided with
respect to the knotted wire design described in . In fact, above a certain temperature, thermal gradients, although
particularly effective at increasing AHE magnitude, proved to be insufﬁcient at obtaining a longlasting effect without
the use of additional stimuli (changes in pressure, current, etc.).
In general we face the need to maximize the thermionic emission of the wires as well as their deuterium loading.
Unfortunately these two parameters require opposite operating conditions: thermionic emission increases at low pres-
sures, but low pressures cause the wire to unload (i.e. it allows excessive release of stored deuterium) hence leading
invariably to the suppression of AHE after some time . This issue was initially tackled by conducting experiments
at a pressure that could prevent excessive release of deuterium from the wires while still allowing electrons to be
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 3
emitted from the Constantan wires coated with low work function elements. Also, the distance between the active
wire and the counter electrode was kept as low as practically possible to promote electron emission without using an
excessive voltage which could lead to localized arcs.
Such conditions are in agreement with the Child-Langmuir equation for the transport of electrons in vacuum
[15,16]. Although to date a working model is not available, our speculations include a role for ionized deuterium
and its interaction with electrons [9,10].
2. Chronology of the Experiments with Constantan Wires
Chronology of the experiments with Constantan wires is shown in Table 1 and the Experimental Design is shown in
3. Wire Treatment and Effect of Diameter and Length on AHE
To prepare the wires, including the oxidation and coating steps, we used the same procedures described in previous pa-
pers . We would like to emphasize that thinner wires consistently provide higher AHE This was observed in several
experiments where we compared 100, 200 and 350 µm wires. The AHE magnitude observed in multiple experiments
seems to ﬁt qualitatively with the ratio between the section area of the oxidized layer formed during the preparation
of the wires and the area of the non-oxidized core. Figure 2 shows these ratios for wires of different diameters based
on SEM observations. We think that the porous and spongy oxidized layers at sub-micrometric dimensionality, upon
reduction, provides a porous region/skin which may be more receptive for deuterium (or hydrogen).
Moreover thinner wires, when heated by direct current in the reactor, feature a signiﬁcantly higher current density
and a larger voltage drop along their ends (similarly to NEMCA  or Preparata  effects).
Table 1. Chronology of experiments with Constantan wires.
Year Main achievement Reference
2011 Beginning of experiments with oxidized wires, of Nickel–Copper alloys in pure H2,D
2or H2/Ar, D2/Ar
mixture atmosphere, ﬁrst measures of AHE in Constantan
2013 Reproducibility of AHE occurrence enhanced after coating the wires with low work function materials (SrO)
and inserting the wires in sheaths of borosilicate glass ﬁbers
2015 AHE occurrence associated with Fe impurities on Constantan wires 
Further improvements in reproducibility after adding Fe, Mn and K to the low work function main coating of
Observation of thermionic emission from the wires in accordance with Richardson law and related Child–
2017 AHE magnitude increased through geometrical arrangements to create thermal gradients along the wires 
Air ﬂow calorimetry introduced for better AHE measures
2018 AHE occurrence empirically associated with thermionic emission of the wires, a counter electrode is intro-
duced to enhance electron emission and AHE
2019 AHE effects stabilized (from hours to days) through high voltage and alternating current stimuli. Observation
of the effect of dielectric barrier discharge on AHE occurrence and magnitude
4F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Figure 1. Evolution of the experimental set-up: Constantan wire reactor (A); grounded counter-electrode is added (B); counter-electrode is
polarized with direct current (C); counter-electrode polarized with alternating current (D).
Giuliano Preparata, in particular studied the AHE generation as function of the total voltage drop along the wire,
assuming that it may behave as if in a coherent state. The coherence phenomena and their relation to LENR, although
controversial, are still the object of investigations .
4. Richardson and Child–Langmuir Laws
In 2014, the authors added an independent wire in close proximity to the active Constantan and observed, at high
temperatures, a weak electrical current ﬂowing when powering the ﬁrst wire .
This current proved to be strongly related to the temperature of Constantan wire and unmistakably the consequence
of thermionic emission (where the treated Constantan is a cathode and the second wire an anode), in close agreement
with the Richardson law [8,9,20]. The recorded current follows a pattern in accordance with the Child–Langmuir law.
Further details can be found in .
Later, our experiments showed that the thermionic effect and the spontaneous voltage between the two wires were
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 5
correlated to AHE occurrence. To date no clear model can explain the association of the thermionic effect and AHE
occurrence, but the consistency of the relationship among the two phenomena has been conﬁrmed in multiple experi-
ments. Also, as mentioned above, the presence of thermal and chemical gradients is considered as being particularly
relevant, especially when interpreting the large effect of knots on AHE magnitude.
5. Knots and Thermal Gradients
In 2018, mostly following a trial and error approach, attempts to further increase AHE focused on the study of different
types of knots, leading eventually to the choice of the Capuchin type (see Fig. 3).
This knot design leads to several hot spots along the wire and comprises three areas characterized by a temperature
difference up to several hundred degrees. The temperature difference between the external spires of the knot and the
internal straight segments may also induce voltage between the spires arising from an ohmic drop along the wire, and
from the different temperatures between the inner and external part of the knot.
We must emphasize that a large AHE rise was observed when introducing an extra voltage between the active wire
(cathode) and a second close wire (anode) through an external power supply.
6. Coil Design
As anticipated, after the study of the wires with strong thermal gradients induced by knots, we realized they have
mechanical and aging limitations, so we initiated various experiments focusing on the use of electric stimuli only. The
Figure 2. Section of wires of different diameter after oxidation and additional treatments. We observe the formation of a porous oxidized layer
that later is reduced by deuterium. The resulting porous skin is especially prone to enhanced deuterium absorption (blue area). These schematic
ﬁgures are based on measurements taken by Scanning Electron Microscopy. The highly loaded zone is in the range of 15–25 µm.
6F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Figure 3. A knot comprised of eight loops heated in air with a direct current (=193 µm, I=1900mA). The external diameter of the coil
is 15–20 mm. Based on a color analysis, the darker area is likely to be at a temperature of <600C, the external spires at about 800C, while the
innermost straight section may reach 1000C. The wire used in experiments is 200 cm long and may have 4–8 knots of this type.
strong empirical association between AHE and thermionic emission guided us toward the use of a second wire with
a positive polarization, to enhance electron emission from the active wire. In a more recent setup, shown in Fig. 4, a
200 µm (or 350 µm) Constantan wire is oxidized and coated with a low work function oxide (SrO). The wire is then
inserted in an original sheath (made by SIGI-Favier) comprised of borosilicate glass ﬁbers (each ﬁber has =5µm)
tightly woven with quartz-alumina ﬁbers (the latter to enhance the temperature resistance of the sheath). The sheath
is also impregnated with the same solution of low work function elements used to treat the wires. The sheathed wire
is then coiled on an iron tube insulated with a thin sheath of quartz-alumina ﬁbers only. The Pt wire has the same
geometrical conﬁguration as the Constantan wires, except for the missing surface treatments and sheath impregnation.
In this conﬁguration the iron tube is used as a counter-electrode to study the effect of voltage bias on AHE occurrence
A schematic of the assembly is shown in Fig. 4.
7. Reactor Assembly
The reactor consists of a borosilicate glass tube (Schott type 3.3); dimension: =33-40 mm,L= 400 mm. A SS-304
tube (carefully cleaned to exclude sulfur), is used as central support to hold in place the coils of wires (V1, V2, V3 in
Fig. 5). This tube encloses an additional thermocouple to measure the mean gas temperature inside the reactor.
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 7
Figure 4. Details of a coil in its ﬁnal assembly. The counter-electrode is a Fe tube covered by an electrical insulating, thin quartz-alumina ﬁber
sheath. The details of construction are the same for Pt and Constantan wires. (Please note that the Constantan coils have an internal thermocouple
contained in a SS tube, the internal thermocouple is not used for the platinum coil whose temperature is measured from its variation of resistance.)
On the outside of the reactor we positioned a sealed source of gamma radiation (Fig. 6) comprised of WTh2%
TIG electrodes (Thoriated Tungsten alloy). This source is located inside a hermetically sealed, 2 mm thick, SS304
tube and has a nominal maximum intensity of 33 kBq. Only X-gamma radiation, speciﬁcally from thorium decay, can
pass through the stainless steel tube and reactor wall to reach the Constantan wire (15 mm away from the source outer
wall). In fact, the use of gamma sources is well known to facilitate electron emission as well as a trigger for avalanche
ionization phenomena especially in the presence of static potential (see addendum B for further information on the
8. Direct Current (DC) Electric Stimuli
Wires are heated by different DC constant-currents at various power levels (usually 40–120 W). The AHE occurs
usually in the range of temperatures of 650–850C, after loading the wires at 2 bar of D2for 2–4 days at 300–500C,
and inducing non equilibrium conditions. This can be executed by decreasing the pressure, up to a minimum of
approximately 10 mbar. In a typical experiment the AHE may last up to one day but then it slowly vanishes. This
behavior may be attributed to: (a) desorption of deuterium from the wire and (b) decrease of effectiveness of the
non-equilibrium conditions that may have triggered AHE release in the ﬁrst instance.
To reactivate AHE release, usually, a new loading cycle at high pressure is needed.
8F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Figure 5. Assembly of the reactor including three coil cartridges, V1 is a platinum coil used mainly for calibrations, V2 and V3 are two active
coils comprised of treated Constantan wires. The V1 temperature is measured using its variation of resistance; the V2 and V3 coil temperatures
are measured by thermocouples inside the coil. An additional thermocouple (in red) is inside a SS tube used as support for the steel frame holding
in place the three coils. This thermocouple is used to estimate the mean internal temperature of the reactor. All the thermocouples are type K, SS
screened; insulated by MgO: 1200C maximum temperature.
In the last two years, we have found that a practical approach to reducing the AHE decline and increasing the AHE
magnitude is the application of a voltage (bias) between the wire and a counter electrode. As already mentioned, we
observed an AHE increase by applying a static positive polarization to the Constantan wire (cathode); later we also
witnessed an effect with a negative polarization.
This led eventually to the choice of an AC stimulus (Fig. 1D) between the Constantan wire and the counter
electrode. Figure 5 shows the electrical connections of each coil used in the latest reactor assembly. The wires are
inserted in theirs sheaths (Figs. 4 and 5) and then wound on a tubular Fe support, macroscopically insulated by a
porous and thin-wall sheath of quartz-alumina ﬁbers.
The excitation voltage is applied between the main wire (which is always heated by direct current, whether it is Pt
or Constantan) and the Fe counter-electrode.
The deuterium loading of the wires is monitored continuously by a dedicated circuit shown in Fig. 7. This allows
us to measure the ratio between the actual resistance (R)of the wire and its resistance (R0)before the ﬁrst deuterium
loading. The circuitry is based on JFET J511 (Constant Current silicon diode, three in parallel, each providing 4.7 mA
of current) and operates at low power only.
The same approach is used also when higher power is applied to the wires (up to 120 W in some experiments, up to
3 A of current with a 350 µm wire). Both circuits are operated in parallel, self-decoupled by a network of high voltage
diodes, as a sum node. To put it in a few words, when Constantan absorbs hydrogen or deuterium, the wire resistance
decreases; the larger the decrease, the larger is the loading.
A second section is designed for the low power (0.1–5 W, ±600 Vp), used to feed the alternating current excitation
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 9
Figure 6. Scheme of the calorimeter, which is comprised of the reactor and calibration heater. Coil cartridges (V1, V2, and V3) as per Fig. 5 are
not shown. T_ext is a thermocouple used to monitor the temperature of the reactor external wall, while T_ss is the thermocouple used to measure
the reactor mean internal temperature.
(AC). It includes several protection networks (based on back to back 150 V, 5 W Zener diodes shown in Fig. 7) put on
each end of the active wires (Constantan and Pt) in parallel to the coaxial connector, to avoid potential failures, to the
main power supply and acquisition system, due to couplings of the high voltage AC pulses. The ±600 Vpare applied
to promote both Richardson–Child–Langmuir (only the positive region of the wave, lower pressures) and Paschen
regimes (corresponding to a pressure of 30–40 mbar in our geometrical conﬁguration, featuring a distance of 2–3 mm
between the electrodes). The rationale of the circuitry is keeping the wires always polarized by a proper amount of
Figure 7. Scheme for the circuitry adopted for R/R0measurements.
10 F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
current, this in order to measure the temperature of platinum wire (V1) and Resistance Ratio (i.e. R/R0)in the case
of Constantans (coils V2 and V3).
This reduction of resistance, with respect to the value of Constantan before absorption (R0), is likely related to the
amount of H (or D) absorbed by the wire similarly to what observed with palladium above a certain loading . That
being said, a precise correlation among absorbed H (D) and resistance is not yet available nor fully understood for the
case of Constantan wires (which as shown in Fig. 2 show nonhomogeneous absorption across their section).
Also, the minimum current injected to maintain the wires polarization, is about 14 mA and is feed by the three
constant current diodes (CCD) in parallel (J511 in the scheme of Fig. 7). When higher current needs to be injected,
a High Power Supply is used (HPS: –120 V, 0–3 A). Appropriate high voltage diodes prevent the current from going
back to the low power supply section (when the high current path is active). The output of HPS has three positions: 1,
connected to Pt (connector V1); 2, connected to the Constantan (connector V2 or V3); three unconnected (NC).
Among others, some explorative tests were made with: (a) unipolar half-wave, positive or negative pulses (see
Appendix A for the circuits used in this case). The Richardson regime, with the related Child–Langmuir current,
occurs at a rather low pressure and the emission intensity of electrons at the surface of the material depends both on
the temperature and the value of the work function of the material. We recall that the electrons boil-off at the surface
of the low work function materials: they create a spatial-charge localized in close proximity of the surface until some
external ﬁeld of positive polarization is applied removing them [3,6,20].
Concerning the Paschen regime, with respect to the original formula developed in 1889 by Friedrich Paschen [22–
28] in free air and parallel plates, we must consider that the use of low work function materials and the presence of the
thoriated tungsten source outside the reactor is likely to inﬂuence the discharge initiation.
Under these conditions, we think that the breakdown voltage would be signiﬁcantly reduced.
9. Alternating Current Electric Stimuli
The AC circuitry that generates 1200 Vpp was applied to the counter-electrode. It is based on two 50 Hz, multiple
output transformers in cascade. This allows us to increase the 230 Vrms (i.e. 324 Vp) of the line to 610 Vpas measured
The current needed for the excitation is rather low, with a limit at 60 mA due to a 10 k⌦limiting resistor. Usually
the current does not exceed 10–20 mA because the triggering voltage of the Paschen effect is approximately 400–500 V
and RMS values up to 5–6 mA, as measured by a Fluke 187 multimeter (BW=100 kHz). The RMS voltage is in the
range 250–280 V, as measured by a Tektronix DMM916 multimeter (BW=20 kHz). For higher accuracy, and better
understanding of waveforms, especially the higher frequency components, the signal at the end of a 10 k⌦resistor is
sent to a Fluke 198C Digital Scope (BW=100 MHz). Some of the most signiﬁcant operating situations are reported in
Figure 10 shows in particular a typical waveform corresponding to a limited coupling between the counter electrode
and the active wire (under high pressure or pure deuterium). As deduced from Fig. 8, the addition of Ar is able to
reduce signiﬁcantly the voltage needed to initiate a discharge. Figure 11 shows instead the waveform observed using a
1:1 molar mixture of Ar and D2at a pressure compatible with discharge occurrence (as per Fig. 8). In these conditions
AHE is substantially increased compared to the case presented in Fig. 10.
Finally Fig. 12 shows the remarkable occurrence of a dielectric barrier discharge, and it is deﬁnitely the most
effective at producing AHE. However, it is rather difﬁcult to maintain and the materials (especially the insulating
sheaths) shows signs of degradation after few hours, probably due to arcing. According to the literature, an increase of
frequency (from present 50 Hz up to values of 10–40 kHz) and optimization of tension and wave form, could limit the
drawback and it is currently under investigation.
That being said, due to the high voltage needed for AC excitation, the injection circuitry and measuring set-up
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 11
Figure 8. Direct current breakdown tension (Vb) of several gases versus pressure and distance between electrodes (p*d) . The addition of
argon to deuterium clearly enables discharges at lower tension.
is currently being improved. This is in order to reduce the value of the 10 k⌦limiting resistor and to boost the peak
current at high voltage. Non-linear circuitry with overall improved high frequency performance, is under consideration.
Some of the waveforms observed by the oscilloscope are reported in Figs. 10–12. Curves in Fig 12 seem to be
associated with the highest AHE. In these conditions a dielectric barrier discharge is clearly occurring.
AHE occurrence was studied using air-ﬂow calorimetry.
The calorimeter consists of an insulated case made of double walls (6.5 cm in total), thick polystyrene whose each
internal surface is covered with multiple reﬂective thin aluminum foil. This apparatus is calibrated using a Nichrome
heater inside the calorimeter case or a platinum wire coil inside the reactor (V1 in Fig. 5) under inert gas (He).
The Ni–Cr heater is contained in a borosilicate tube having dimensions similar to the active reactor. Both the heater
and the reactor are placed in close proximity. They are covered by several corrugated layers of 40 µm thick Al foils
with one black side. An overview of the assembly is shown in Fig. 6. The fan is 5 cm wide, operates in suction mode,
and has a nominal air ﬂow of 4.445 l/s at normal pressure and temperature (NPT), and it rotates at 75 Hz. Its revolution
rate is monitored, and the measurement is logged in the acquisition system. The overall average coefﬁcient of heat
exchange during calibrations (e.g. in the restricted power range of 90–110 W) with the Ni–Cr heater or platinum wire is
12 F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Figure 9. Scheme of the high voltage-low current circuitry adopted for AC excitation. The Rlimit and current measuring resistance usually has a
value of 10 k⌦(T1, T2, and T3 refer to the counter electrodes of each coil which is the iron tube shown in Fig. 4).
approximately 0.20C/W and is consistent with the values of air ﬂow, density, pressure and air humidity (which is kept
almost stable at 45–55% of RH by the air conditioning system of the laboratory) and heat capacity in the range of air
temperature inside the calorimeter (20–60C). Precautions to increase internal air turbulence are also taken to prevent
air stratiﬁcation which could affect the measures. A selection of over 80 tests are reported in Table 2, Appendix B.
Figure 10. Voltage drop along the limiting-measuring resistor of 10 k⌦. Red is at test point A, blue at test point B. Current is the green color line.
Typical waveforms in mild condition of excitation, i.e. not Dielectric Barrier Discharge (DBD) conditions. Even the Paschen regime (starting from
about 400 V) looks self-quenched, perhaps due to the excessive value of the resistance (10 k⌦resistor in Fig. 10).
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 13
AHE is estimated as follows:
A1= Tout Tin
(C/W) Calibration values,(1a)
A2= Tout Tin
(C/W) Active wire values,(1b)
where Tout and Tin are the air temperatures measured at the outlet and inlet of the calorimeter, respectively, as shown
in Fig. 6.
Further details on the adopted calorimetric technique can be found on the paper summarizing the presentation at
In a particularly impressive experiment, 18 W of AHE were observed for an input power of 99.7 W (line #38 of
Table 2 in Appendix B), recorded when using a 200 µm wire (coil V2 in Fig. 2) at a temperature of 716C. The
counter-electrode excitation consists of +270 V bias and 3 mA current, the behavior of R/R0was oscillating over
time. The effect lasted over 5 h.
Figure 11. Similar to the case of Fig. 10 but with larger current. The current starts at a voltage value close to 400 V, as expected according to the
threshold voltage of the gas involved.
14 F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Figure 12. Typical waveform that seems to be the most efﬁcient to increase the AHE.
Afterward AHE decreased to 9.5 W (line #39), perhaps due to air intake from a leak. In fact, the pressure increased
from about 300 up to about 316 mbar. Anyway, the effect had a remarkable time span of over 15 h. When the polarity
was changed from positive to negative (line #40), AHE decreased from 9.5 to 7.4 W. The shift (line #41) from unipolar
negative to bipolar oscillation (±600 Vp, 50 Hz) increased AHE from previous 7.4 to 10.7 W, the effect lasted about
4 h. Reducing the pressure from 341 to 98 mbar (line #42) the effect increased from 10.7 to 14.5 W, always under
AC oscillation and current (rms value) of 2–3 mA. The effect lasted 4 h. After the interruption of the AC stimulus
(line #43) leakage was observed, causing a pressure increase from 98 to 250 mbar, this was followed by a reduction
of AHE from 14.5 to 2.4 W. AHE slowly vanished following stabilization of R/R0(that was unstable and oscillating
proportionately to AHE).
When AC oscillation (line #44) was resumed at a constant pressure of 250 mbar, AHE rise again, from 2.4 to 9.2 W.
In general, much lower AHE values were observed when using the larger diameter wire coil V3 (350 µm). Eventually
the only way to recover large values of AHE (i.e. 14.4 W, line #59), was to power 200 µm wire (V2) add some Ar to
the gas mixture, keep the pressure relatively low (36 mbar), and use AC excitation to the counter electrode.
From the collected data the following conclusions can be drawn.
(a) The AHE occurrence is correlated with fast loading or unloading of the wire. In the case of unloading
however, after a short time, the AHE vanishes.
(b) When loading/unloading occurs slowly, AHE is signiﬁcantly reduced.
(c) A state of oscillation seems to be the most efﬁcient since it produces AHE for a longer time with respect to
fast loading or unloading (especially when a dielectric barrier discharge occurs).
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 15
(d) Loading and unloading occurrence, as assumed from R/R0and variation in reactor pressure, strongly support
the key role of deuterium ﬂux (see  for a deﬁnition of ﬂux).
There are additional external conditions, such as high temperature, low pressure, purity of the gas that facilitate the
AHE. In any case, after some time, even the optimal conditions described above are not sufﬁcient to maintain AHE
release. That being said, the major ﬁnding we would like to emphasize is the ability of the counter-electrode stimulus
to keep the AHE active for longer times, perhaps indeﬁnitely.
Also, the role of non-equilibrium conditions and ﬂux were suggested by several researchers [30–38] since the
beginning of Cold Fusion experiments. Convincing proofs being said, the set of experiments summarized in Table 2 of
the present work consistently shows a strong correlation between a change in loading/pressure and the occurrence of
AHE, hence providing a strong support to the ﬂux model or hypothesis. Also, although most of the tests here described
are in agreement with the ﬂux model, some results are still difﬁcult to interpret. We think that this could be due to
accidental contamination of the deuterium due to an insufﬁciently air-tight glass reactor, especially at high temperature
and low pressure.
Moreover, a critical analysis of the data collected in Table 2 (Appendix B) allows us to highlight a series of
observations or possible generalizations on the best conditions enabling AHE release for the selected reactor geometry:
(1) Temperature must be as high as possible, provided that sintering of the spongy surface does not occur. Also,
high temperature is one of the key factors for electron emission from low work function materials. We speculate
that a high intensity emission may interact with deuterium (or hydrogen) leading to useful phenomena. This
last statement is purely based on associations during experiments (i.e. between thermionic emission and AHE).
(2) Low pressure is useful to increase the eemissions. However, below a certain pressure the effect may be
deleterious due to excessive deuterium release (unloading) from the wires. We would like to highlight that the
occurrence of a dielectric barrier discharge (Fig. 13) is associated with a remarkably intense AHE. Although
at this stage we would like to avoid venturing into a discussion of possible reaction mechanisms, we recognize
some analogies with previous work and that of Randell Mills [39–42] and Jacques Dufour [43,44].
(3) The addition of low-thermal conduction noble gases (like Ar or Xe) is generally useful to increase the temper-
ature inside the reactor core and promote the Paschen regime, when the counter-electrode has sufﬁciently high
(4) High DC voltages along the active wire are useful (perhaps due to NEMCA and/or Preparata effects). As a
consequence, thinner wires are usually more efﬁcient at producing AHE.
(5) The effect of AC has to be fully explored in all of its potential (varying frequency, voltage, waveform, bias,
and/or asymmetries). Nevertheless, we observed an unexpected but clear correlation with the negative side
of AC wave and an increase of the temperature in the reactor core when certain conditions of temperature
and pressures are fulﬁlled. In general, AC stimuli seems to counteract the AHE decline observed in previous
(6) The ﬂux of deuterium trough the active material (Constantan) seems to be the most important factor driving
the AHE generation. Based on experimental observations, we speculate that inducing oscillations of ﬂux may
be the best method for triggering or increasing AHE.
(7) Contamination of the reactor atmosphere (e.g. by air and/or degradation of glassy sheaths) has a deleterious ef-
fect on AHE. Unfortunately, due to budget constraints, up to now we could not afford a Residual Gas Analyzer
(RGA) placed in-line with the reactor to diagnose this problem.
Our present work aims at preventing the issues of the described experimental setup such as the frequent leakages
and poor control of gas compositions. This will be achieved with a new stainless steel reactor equipped with residual
gas analysis (RGA). We are also working at optimizing the electronics used as AHE stimulus and for DBD plasma
16 F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
generation, as well as at ﬁnding the optimal operating conditions both with conventional high tension, medium-high
frequency generators, as well with pulsed DC power supplies.
The experimental work described in this paper was presented at ICCF22 Conference (Assisi, September 8–13, 2019).
This work was carried out at INFN-LNF while some trials were conducted at the premises of a Metallurgical Company
of North Eastern-Italy with independent instruments and personnel. This Company has also has provided some ﬁnan-
cial support since 2011. SIGI (Società Italiana Guaine Isolanti) Favier, France, designed and produced dedicated glass
ﬁber sheaths in close collaboration with the above-mentioned Metallurgical Company. From October 2017 Lega Nord,
an important political Group in Italy, enabled the continuation of F. Celani’s experiments in the Frascati Laboratory
of INFN. Special thanks to Francesco Malagoli, Filippo Panini, Paolo Varini. All have followed LENR development
for many years, in line with a political program focused on the protection of the environment. Antonino Cataldo and
Stefano Bellucci (NEXT collaboration) performed SEM and EDX analysis at INFN-LNF. Some of the expenses to per-
form experiments and for travel and food, were supported by IFA group-Italy. We thank the Anthropocene Institute,
USA (i.e. Carl Page and Frank Ling) for providing economic support so that two of our collaborators could attend the
ICCF22. We thank Hideki Yoshino, CEO of Clean Planet Company, Japan, for providing economic support enabling
another of our collaborators to attend the ICCF22. We are indebted to Luca Gamberale, one of the last collaborators
of Prof. Giuliano Preparata still active in the LENR –AHE ﬁeld, for the critical reading of our manuscript. We are also
indebted to Jed Rothwell for proofreading the manuscript, for his scientiﬁc suggestions and for improving the English
grammar, as he has done for several years.
 F. Celani, E.F. Marano, A. Spallone, A. Nuvoli, B. Ortenzi, S. Pella, E. Righi, G. Trenta, F. Micciulla, S. Bellucci, S.
Bartalucci and M. Nakamura, Experimenal results on sub-micro structured Cu–Ni alloys under high temperatures hydro-
gen/deuterium interactions, Chem Material Res 3(3) (2013) 25–76.
 F. Celani, E.F. Marano, B. Ortenzi, S. Pella, S. Bartalucci and S.B. F. Micciulla, Cu–Ni–Mn Alloy wires, with improved sub-
micrometric surfaces, used as LENR device by new transparent, dissipation-type calorimeter, J. Condensed Matter Nucl. Sci.
13 (2014) 56–67.
 F. Celani, G. Vassallo, E. Purchi, S. Fiorilla, L. Notargiacomo, C. Lorenzetti, A. Calaon, B. Ortenzi, A. Spallone, M. Naka-
mura, A. Nuvoli, P. Cirilli, P. Boccanera and S. Pella, Improved stability and performance of surface-modiﬁed Constantan
wires, by chemical additions and unconventional geometrical structures, J. Condensed Matter Nucl. Sci. 27 (2018) 9–21.
 F. Celani, A. Spallone, B. Ortenzi, P.S, E. Purchi, F. Santandrea, S. Fiorilla, A. Nuvoli, M. Nakamura, P. Cirilli, P. Boccanera
and L. Notargiacomo, Observation of macroscopic current and thermal anomalies, at high temperatures, by hetero-structures
in thin and long constantan wires under H2gas, J. Condensed Matter Nucl. Sci. 19 (2016) 29–45.
 F. Celani, C. Lorenzetti, L. Notargiacomo, E. Purchi, G. Vassallo, S. Fiorilla, B. Ortensi, M. Nakamura, A. Spallone, P.
Boccanera, S. Cupellini and A. Nuvoli, LENR phenomena in Constantan; a steady progress toward practical applications:
observation of Zener-like behaviour, in air atmosphere, of Constantan submicrometric wires after D2–Xe loading–deloading
and related AHE, in 12th Int Workshop on Anomalies in Hydrogen Loaded Metals, Asti, 2017.
 F. Celani, B. Ortenzi, A. Spallone, C. Lorenzetti, E. Purchi, S. Fiorilla, S. Cupellini, M. Nakamura, P. Boccanera, L. No-
targiacomo, G. Vassallo and R. Burri, Steps to Identify main parameters for AHE generation in sub-micrometric materials:
measurements by isoperibolic and air-ﬂow calorimetry, J. Condensed Matter Nucl. Sci. 29 (2019) 52–74.
 F. Celani and C. Lorenzetti (Eds.), Electrically induced anomalous thermal phenomena in nanostructured wires, in Cold
Fusion, Chap 7, Elsevier, Amsterdam, 2020, pp. 101–113.
 F. Celani, C. Lorenzetti, G. Vassallo, E. Purchi, S. Fiorilla, S. Cupellini, M. Nakamura, P. Boccanera, R. Burri, B. Ortenzi,
A. Spallone and P. Cerreoni, First evaluation of coated Constantan wires comprising Capuchin knots to increase anomalous
heat and reduce input power at high temperatures, J. Condensed Matter Nucl. Sci. 30 (2020) 25–35.
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 17
 F. Celani, C. Lorenzetti, G. Vassallo, E. Purchi, S. Fiorilla, S. Cupellini, M. Nakamura, P. Boccanera, R. Burri, P. Cerreoni
and A. Spallone, Effects of super-Capuchin knot geometry, and additional electric ﬁelds, on hydrogen/deuterium absorption:
related AHE on long and thin Constantan wires with sub-micrometric surfaces at high temperatures, in 2019 LANR/CF
Colloquium at MIT-USA, Cambridge, MA 02139 (USA), March 23–24, 2019.
 F. Celani, C. Lorenzetti, G. Vassallo, E. Purchi, S. Fiorilla, S. Cupellini, M. Nakamura, P. Cerreoni, P. Boccanera, R. Burri and
A. Spallone, Unexpected effects due to voltage waveform at anode, in gaseous LENR experiments based on sub-micrometric
surface coated Constantan wires., in Terzo Convegno Assisi nel Vento, Domus Laetitiae, Assisi (PG), Italy, May 17–19, 2019.
 S. Romanowski, W. M. Bartczak and R. Wesołkowski, Density functional calculations of the hydrogen adsorption on transi-
tion metals and their alloys. an application to catalysis, Langmuir 15 (18) (1999) 5773.
 W. Brückner, S. Baunack, G. Reiss, G. Leitner and T. Knuth, Oxidation behavior of Cu–Ni(Mn) (constantan) ﬁlms, Thin
Solid Films 258 (12) (1995) 252.
 B.S. Ahern, K.H. Johnson and H.R. Clark, Method of maximizing anharmonic oscillations in deuterated alloys. Patent
 D. Ugura, A.J. Storm and R. Verberk, Quantiﬁcation of the atomic hydrogen ﬂux as a function of ﬁlament temperature and
H2ﬂow rate, J Vacuum Sci. Technol 30 (3) (2012) 1–6.
 K. Jensen, Introduction to the Physics of Electron Emission,Child–Langmuir Law, Chap. 16, Wiley 2017.
 Y.L.Y Lau, Electron emission: from the Fowler–Nordheim relation to the Child–Langmuir law, Phys Plasmas 1(1994)
 C.G. Vayenas, S. Bebelis, I.V. Yentekakis, S. Neophytides and J. Yi, Ion spillover as the origin of the NEMCA effect, Studies
in Surface Science and Catalysis 77 (1993) 111–116.
 M. Cola, E.d. Giudice, A.D. Ninno and G. Preparata, A Simple Model of the Cohn-Aharonov Effect in a Peculiar Electrolytic
Conﬁguration, Vol. 70, Lerici (SP)-Italy, SIF Bologna, 2000, pp. 349–358.
 Luca Gamberale, Dynamical realization of coherent structures in condensed matter, in Invited paper at IWAHLM13, October
5–8, 2018, Greccio (RI)-Italy, 2018.
 O.W. Richardson, Thermionic Phenomena and the Laws which Govern Them. Nobel lecture, 1929.
 Y. Sakamoto, K. Takai, I. Takashima and M. Imada, Electrical resistance measurements as a function of composition of
palladium–hydrogen(deuterium) systems by a gas phase method, J Phys.: Condensed Matter 8(19) (1996) 3399–3411.
 F. Paschen, Ueber die zum Funkenübergang in Luft, Wasserstoff und Kohlensäure bei verschiedenen Drucken erforderliche
Potentialdifferenz, Annalen der Physik 273 (5) (1889) 69– 75.
 D. Mari´
c, M. Savi´
c, J. Sivoš, N. ˘
Skoro, M. Radmilovi´
c, G. Malovi´
c and Z. Petrovi´
c, Gas breakdown and sec-
ondary electron yields, Eur. Phys. J.D68 155 (2014) 1–7.
 L.F. Berzak, S.E. Dorfman and J. Smith, Paschen’s Law in Air and Noble Gases, Berkley, USA, 2006, pp.1–14.
 E.M. Bazelyan and Y.P. Raizer, Spark Discharge, CRC Press, Boca Raton, FL, USA, 1998, 1998.
 I. Donko and Z. Korolov, Breakdown in hydrogen and deuterium gases in static and radiofrequency, Phys. Plasmas 22
 M.W. Childs, Ion generator apparatus, United States Patent US10398015B2, 27 8 (2019).
 D. Fisher and J.d. Bitetto, Townsend ionization coefﬁcients and uniform ﬁeld breakdown, Phys. Rev. 104 (1956) 1213.
 M.A. Lieberman and A.J. Lichtenberg, in Principles of Plasma Discharges and Materials, Vol. 1, 2nd Edn, Wiley Blackwell,
2005, p. 700.
 F. Celani, Talk at the ﬁrst workshop on cold nuclear fusion, in Summary by Richard L. Garwin, Nature 338 (1989) 616–617
https://doi.org/10.1038/33861, E. Majorana Centre for Scientiﬁc Culture, Erice (Italy), 1989.
 M. Swartz, Quasi-one-dimensional model of electrochemical loading of isotopic fuel into a metal, Fusion Technol. 22 (2)
 G.C. Fralick, A.J. Decker and J.W. Blue, Results of an attempt to measure increased rates of the reaction D2+D2yields
He-3 +n in a nonelectrochemical cold fusion experiment, NASA-TM-102430, E-5198, NAS 1.15:102430 , Cleveland, 1989.
 Y. Arata and Y.C. Zhang, Reproducible cold fusion reaction using a complex cathode, Fusion Technol 22 (2) (1992) 287–
 Y. Iwamura, T. Itoh and M. Sakano, Nuclear products and their time dependence induced by continuous diffusion of deu-
terium through multi-layer palladium containing low work function material, in 8th Int Conf Cold Fusion, Lerici (La
18 F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
 M.C.H. McKubre, S. Crouch-Baker, A.M. Riley, S.I. Smedley and F.L. Tanzella, Excess power observations in electrochem-
ical studies of the D/Pd system; the inﬂuence of loading, in Frontier of Cold Fusion, Proc. ICCF3 Nagoya, 1992.
 Y. Iwamura, T. Itoh, M. Sakano, S. Sakai and S. Kuribayashi, Low energy nuclear transmutation in condensed matter induced
by D2gas permeation through Pd complexes: correlation between deuterium ﬂux and nuclear products, in Proc. of ICCF10,
Condensed Matter Nuclear Science, Cambridge, MA, 2006.
 Y. Iwamura, T. Itoh and N. Gotoh, Characteristic X-ray and neutron emission from electrochemically deuterated palladium,
in Proc. 5th Int. Conf. Cold Fusion, Monte Carlo , Monaco, 1995.
 T.O. Passell, Use of helium production to screen glow discharges for low energy nuclear reactions (LENR), in American
Physical Society. APS March Meeting 2011. March 21–25, 2011, Abstract ID Y33.008.
 R.L. Mills, W.R. Good, J. Phillips and A.I. Popov, Lower-energy hydrogen methods and structures, Patent US6024935A,
 R.L. Mills and P. Ray, Spectral emFractional quantum energy levels of atomic hydrogen from a helium–hydrogen plasma
and the implications for dark matter, Int. J. Hydrogen Energy 27(3) (2002) 301–322.
 R.L. Mills, P.C. Ray, M. Nansteel, X. Chen, R.M. Mayo, J. He and B. Dhandapani, Comparison of excessive Balmer /spl
alpha/ line broadening of inductively and capacitively coupled RF, microwave, and glow-discharge hydrogen plasmas with
certain catalysts, IEEE Trans Plasma Sci 31 (3) (2003) 338–355.
 B. Holverstott, Randell Mills and the Search for Hydrino Energy, KRP History, 2016.
 J. Dufour, J. Foos and J.P. Millot, Measurement of excess energy and isotope formation in the palladium–hydrogen system,
in 5th Int Conf on Cold Fusion, Monte-Carlo, Monaco, 1995.
 J. Dufour, J. Foos and J.P. Millot, Excess energy in the system palladium/hydrogen isotopes. measurement of the excess
energy per atom hydrogen, in 5th Int Conf on Cold Fusion, MonteCarlo, Monaco, 1995.
Appendix A. Auxiliary Circuitry for Explorative Tests
Auxiliary circuitries were developed to study:
(A) the effects of unipolar excitation at 50 Hz, both positive and negative. Schematic shown in Fig. 13
(B) current ﬂowing between cathode and anode. DC level at maximum allowable voltages, +-600 V. Sketch shown
in Fig. 14
Figure 13. Circuitry to generate unipolar pulses, at 50 Hz, by a network of fast diodes and R(660 k⌦grounded). Such circuitries allowed
to evaluate the effect of repetitive unipolar pulses from the point of view of AHE stimulation. The results were used to optimize the operating
conditions of the reactor (gas, temperature and pressure).
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 19
Figure 14. The simple circuitry used to generate unipolar high voltages in DC, by means of a peak detector system (D, Capacitor). Adding an
ammeter between the output of the circuitry and the counter electrode it was possible to measure the current, in DC conditions, between the two
wires of the reactor while changing gas, temperature and pressure.
Table 2 summarizes over 80 tests performed during two months of experiments using Constantan wires, 1.7 m long,
with a diameter of 200 or 350 µm. During these experiments the active wire polarity was kept negative and the
extremity of each wire was grounded; the power supply was operated in the constant-current mode. The table includes
the following data:
C1 Identiﬁcation of the experiment, time [s] since the start of speciﬁc data logging.
C2 Wire diameter (mm).
C3 Electric input power (W), Voltage along the wire (V), Current (A).
C4 Gas type, pressure (mbar).
C5 Temperature at the core of each tube/cartridge used for the Constantan wires (inside the Fe counter-electrode);
the R/R0value of the wire; the trend of its variation over time (reported on the last 10 ks) as observed in the
plot of raw data.
The wire loading during the experiments was classiﬁed, as follows:
C5.1 Increase of Loading (IL), corresponds to a R/R0decrease; it can be Slow (S) or Fast (F)
(e.g. IL_S means slow increase of loading).
C5.2 Decrease of Loading (DL), corresponds to a R/R0increase; it can be Slow (S) or Fast (F).
C5.3 Oscillation. The R/R0values oscillate around a certain mean value. The larger is the amplitude of oscillations,
the larger AHE is.
C5.4 Constant. The R/R0not varying signiﬁcantly over time. In this conditions AHE is absent.
We assume that these behaviors are closely correlated with a ﬂux of the active species thorough the surface
and/or bulk of the wire;
C6 Electric conditions of the counter-electrode, i.e. V,I, in DC or AC.
C7 AHE values (W), calculated using Eq. (1)(1–3). Maximum value measured was +18 W with 100 W input.
C8 Short comments on the experimental conditions and results.
20 F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Table 2. Summary of the most important operating conditions and results collected over two months of experiments.
C1 C2 C3 C4 C5 C6 C7 C8
or 50 Hz
–0.7 10 July 2019. File started
03 July 2019, 16 h 44 m af-
ter several calibrations using
nichrome and platinum heaters
+8.7Gas leak. Fast deuterium de-
loading. Higher temperatures
and fast unloading effective to
+7.8Gas leak. Fast de-loading
+0.5Gas leak. Slow unloading.
The rate of unloading is a key
factor to get AHE.
+0.2R/R0almost constant. No
+4.5Fast unloading. AHE recov-
+2.8Low speed loading, reduced
+8.6Increasing loading, noisy
The AHE increased largely,
perhaps due to R/R0oscilla-
+6.6R/R0almost ﬂat but with sev-
eral instabilities. AHE present
+4.4R/R0almost ﬂat but with in-
stabilities. Also the oscillations
are useful to get AHE
Calorimeter opened and re-
closed to repair a large gas leak.
New ﬁle 170719_12:01
–0.5 In almost static conditions and
high pressure no AHE, al-
though some loading
+0.8Gas leak. Pwat V2. Very slow
loading. Some R/R0instabil-
ity. Similar to test #12 but some
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 21
Table 2 continued
–0.7 Gas leak. 50 ks mea-
Very long measures,
180 ks. R/R0ﬂat. No
Long duration mea-
sures. R/R0ﬂat. No
tions were the source
+10.1 Forced pressure re-
origin of AHE. Short
+9.7 Forced pressure re-
+7.7 Forced pressure re-
No thermal equilib-
+6.0 Forced pressure re-
No thermal equilib-
+4.0 Forced pressure re-
No thermal equilib-
+5.9 Forced pressure re-
No thermal equilib-
+5.5 Forced pressure re-
No thermal equilib-
22 F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Table 2 continued
+8.1 Forced pressure re-
No thermal equilib-
(>60 h). Leak-
age: air intake, ini-
tial 158 mbar at
has positive Polar-
ization: some AHE,
at least at for short
vanished, even en-
–0.9 Pol. Neg. long time
of loading: some
+1.1Leakage air intake
an initial improve-
ment, later R/R0
+3.4Forced pressure re-
Several test with
DC ﬁeld Pos. and
Indications that a
change of polarity
could be useful to
DC ﬁeld removed
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 23
Table 2 continued
+2.5Forced pressure re-
and recovery. Fast
with ﬁeld. R/R0
noisy. First time ob-
served AHE not de-
creasing over time
with power constant
80 to 90 W.
crease of R/R0, os-
cillations of R/R0
90 to 100 W.
Fast increase of
R/R0. Osc. large
+9.5Long duration 50
ks, at 100 W, DC
ﬁeld +300 V. R/R0
+7.4Test with negative
Negative ﬁeld effect
AC, 260 V
ﬁrst time. RMS val-
ues. Requiv: 100 k⌦.
AC, 260 V
several times. AC
on. Large R/R0in-
24 F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Table 2 continued
meas. Air intake:
AC, 280 V
AHE, i.e. 2.4–9.2
AC, 260 V
+0.2Active wire 0.35
mm. First time
AC, 262 V
decreased. No AHE
AC, 262 V
spikes at AC, R/R0
AC 260 V,
AHE, although AC
AC, 263 V
+0.9Forced pressure re-
duction. No effect
to recover AHE
AC, 262 V
+2.1Forced pressure reduction.
Increase of internal
temperature and AHE
AC, 293 V
+3.1After vacuum new gas
(Ar=D270 mbar at RT ),
Wire switch (V3 to V2).
Smaller wire diameter, i.e.
higher DC voltage,
AC, 293 V
+2.2Forced pressure reduction
R/R0stable last 2 h
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 25
Table 2 contin-
AC, 293 V
+9.1Forced pressure reduction.
AC, 293 V
+11.3Forced pressure reduction
R/R noisy. Further increase
of AHE. HF self-pulses
AC, 299 V
+9.8Leakage air intake. Several
pressure reductions. AC
current almost vanished
AC, 299 V
+10.2Several forced pressure
reduction. AHE correlated
with fast R/R0variation,
oscill. high temperature
AC, 299 V
+8.7Leakage air intake.
Reducing local temperature
NO AC +6 Forced pressure reduction.
One of co-factor effects
for AHE generation is AC
stimulation, although HT
AC, 290 V
+14.4Forced pressure reduction.
Large AHE. Geiger-Muller
gamma detector several
times in alarm (4 BKG).
–0.7 New ﬁle: 19082019,
13:37 Over 15 days
operation at low power.
AC, 247 V
+0.1Reducing pressure and
adding AC stimulation
induced some AHE
AC, 270 V
–0.1 AC excitation ended 2 h
NO AC –1.4 Without AC the weak
26 F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Table 2 continued
AC, 247 V
+0.6Forced pressure reduction.
AC ﬁeld from 20 ks. No HF
discharge. Weak AHE
AC off since 1 h. R/R0
decreased but AHE weak
–1.3 AC off since 16 h.
AC, 290 V
+1.5AC ﬁeld since 4 h
Recovering of AHE
NO AC +0.1Pressure reduced. AC
stopped: AHE vanished.
AC, 290 V
+2.6Forced pressure reduction,
AC ON since 2 h.
–1.8 NO AC. Pressure increased.
R/R0stable; AHE absent
AC, 280 V
+1.2Forced pressure reduction.
AC, 253 V
–1.3 AC seems NOT effective
to stimulate AHE without
AC, 253 V
+3.2AC ON, sometimes HF.
value of local high
temperature (760C) is
AC, 260 V
+7 AC ON, some spontaneous
HF. Forced pressure
reduction. Combined effect
of higher temperature,
low pressure-AC excitation is
F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28 27
Table 2 continued
AC, 290 V
+2.8AC ON, leakage air intake.
AHE reduction (7.2–2.8)
because: pressure increasing,
lower AC, lower temperature
AC, 290 V
+1.8After vacuum, fresh D2
(380 mbar at RT).
Increasing of loading. Noisy.
Some AHE, although
low power and temperature.
Flux of D2looks important
AC, 300 V
–0.3 Re-activated V2. Slow
loading speed. No AHE,
although AC oscillation but
no HF components.
Pressure excessive and
temperature not sufﬁcient
AC, 290 V
+4.9Forced pressure reduction.
effects with HT.
AC, 290 V
+115 Forced pressure reduction.
R/R0noisy and decreasing.
HT, low pressure, oscill.:
ingredients to get AHE
AC, 290 V
+8.3AC polarization started.
Leakage, air intake observed.
AC, 290 V
+13.0AC always active. R/R0
noisy and decreasing fast.
The AC keeps AHE
stable over time
AC, 290 V
+12.8Several pressure reduction
steps. AC always active.
R/R0noisy and decreasing.
Although air intake
AHE almost stable
28 F. Celani et al. / Journal of Condensed Matter Nuclear Science 33 (2020) 1–28
Table 2 continued
AC, 290 V
+11.2Long duration measures.
AC ON. Leakage and air
intake occurred. R/R0noisy
and decreasing. The
combined effect of high
temperature, AC oscillation
and sufﬁciently low pressure
overcome the deleterious
effect of air intake even
for long times (>14 h).
Last measurement before
(1) After the ICCF22 conference we received enquiries whether we have a theory supporting the correlation be-
tween AHE occurrence and electron emission. Unfortunately to date we can only speculate that electron
emission may cause D+ions in gaseous phase to move toward the surface of the Constantan wire, possi-
bly contributing to the D ﬂux or inducing extreme localized gradients beneﬁcial to the manifestation of AHE
(especially on the nanostructures present on the surface of the wire).
(2) The gamma source contains 10 g of 232Th in form of Thoriated Tungsten (i.e. electrodes used for TIG welding).
Thorium is dispersed at 2% concentration w/w in a matrix of W. The speciﬁc activity of 232Th is 4.07 ⇥103
Bq/g, mostly alpha and beta radiations. In addition there are several gamma, even at high energies (2614
keV), due to his decay products (228Ac, 212 Bi, 212 Pb, 212Po, 224 Ra, 228Ra, and 208 Tl). The tube were the
material is inserted is a 2 mm tick stainless steel tube, hermetically closed. In short, the measured gamma
activity, measured using just a simple Geiger Muller detector, is over 10 times larger of local background
(35–40 µRem/h). Moreover, a 3⇥3 inch NaI(Tl) detector was successfully used to identify the 232 Th gamma
peaks up to 2 MeV of energy.