Vantasner AG device program: prior art briefing. Concept source read 2026-10-21; every citation below was confirmed by web search on 2026-10-21. Records are reported neutrally: who, when, venue and digital object identifier (DOI), setup, materials, loading, excitation, conditions, and reported outputs. This cluster is the quantitatively established core of condensed-matter nuclear science: accelerator teams shooting kiloelectronvolt deuterons into deuterated metals measure reaction yields far above the bare-nucleus curve, and the fitted energy shift, called the screening potential, runs from tens to hundreds of electronvolts depending on the host. Those numbers are the bridge between chemical-scale energies and nuclear rates, and they are the numbers our piezo-gap acceleration concept multiplies against.
Neutral record table
| who | when | venue / DOI | setup | materials | loading | excitation | conditions | reported outputs |
|---|---|---|---|---|---|---|---|---|
| U. Greife and co-workers (Ruhr-Universitaet Bochum) | 1995 | Zeitschrift fuer Physik A 351: 107 (1995) | gas-target deuteron-deuteron (D-D) fusion at very low beam energy; the baseline experiment for the field | deuterium gas target | molecular D2 | deuteron beam, 5 to 10 keV class | precision cross sections below 10 keV center-of-mass | the record shows a gas-target screening energy of 25 plus or minus 5 eV, quoted by later groups as the atomic-limit baseline |
| H. Yuki and co-workers (Tohoku University) | 1998 | JETP Letters 68: 823-829 (1998), DOI 10.1134/1.567800 | deuteron beam on deuterated metal targets; d(d,p)t yields at low energy | metal targets including titanium and gold | deuterium absorbed in the metal target | low-energy deuteron beam | sub-10 keV class beam energies | the authors report enhanced D-D yields in metallic environments relative to gas, among the first metal-host measurements of this kind |
| K. Czerski, A. Huke, A. Biller, P. Heide, M. Hoeft, G. Ruprecht (Technische Universitaet Berlin) | 2001 | Europhysics Letters 54 (4): 449-455 (2001), DOI 10.1209/epl/i2001-00265-7 | deuteron implantation into three metal targets to saturation stoichiometry; thick-target yields of d(d,p)t and d(d,n)he3 at four detector angles 90 to 150 degrees | aluminum, zirconium, tantalum foils implanted with deuterium (D+, D2+ beams) | implantation to saturation, near chemical stoichiometry | 5 to 60 keV deuteron beams; 60 kV cascade accelerator, high-voltage stability about 10 eV | thick targets; on-line deuteron-density monitoring via proton yield | the authors report screening energies of 190 plus or minus 15 eV (Al), 297 plus or minus 8 eV (Zr), 322 plus or minus 15 eV (Ta), about ten times the 25 plus or minus 5 eV gas value and a clear host-material dependence; theoretical estimates (about 20 eV gas, about 80 eV palladium bound-state limit) fall far below |
| F. Raiola and co-workers, LUNA Collaboration (Laboratory for Underground Nuclear Astrophysics, LNGS and partners) | 2002 | European Physical Journal A 13: 377-382 (2002), DOI 10.1007/s10050-002-8766-5 | accelerator screening measurement of d(d,p)t in tantalum | deuterated tantalum target | deuteron implantation | low-energy deuteron beam (LUNA 50 kV class accelerator) | underground laboratory conditions | the authors report a tantalum screening energy of 309 plus or minus 12 eV, matching the Berlin value within errors |
| F. Raiola, P. Migliardi, L. Gang and co-workers (Bochum, Atomki, LUNA partners) | 2002 | Physics Letters B 547: 193-199 (2002), DOI 10.1016/S0370-2693(02)02774-0 | d(d,p)t screening across deuterated metals; ordering against the periodic table | multiple deuterated metal targets, flagship result palladium | deuteron implantation into metals | low-energy deuteron beams | same beam-energy class as the Berlin campaign | the authors report a palladium screening energy of 800 plus or minus 90 eV (quoted by Czerski and co-workers 2004), the largest value in the d(d,p)t record, and periodic-table ordering of screening strengths |
| J. Kasagi and co-workers (Tohoku University) | 2002 | Journal of the Physical Society of Japan 71: 2281 (2002) | deuteron beam screening measurement on palladium | deuterated palladium | deuteron loading of palladium | low-energy deuteron beam | keV-class beam energies | the authors report a palladium screening energy of 310 plus or minus 50 eV (quoted by Czerski and co-workers 2004), agreeing with the Berlin palladium value |
| C. Bonomo and co-workers (Bochum, INFN partners) | 2003 | Nuclear Physics A 719: 37c (2003), DOI 10.1016/S0375-9474(03)00955-2 | screening measurements with in-situ surface cleaning by krypton sputtering | aluminum and other metal targets | deuteron implantation | low-energy deuteron beams; sputter cleaning immediately before measurement | high-vacuum conditions, re-oxidation within minutes at 10 to the minus 8 mbar for reactive metals | the authors report that sputter-cleaning raises the measured screening energy for aluminum and other metals; Czerski and co-workers 2004 attribute the small early values for zirconium (80 plus or minus 20 eV class) to surface re-oxidation |
| F. Raiola and 26 co-workers (Bochum-led collaboration) | 2004 | European Physical Journal A 19 (2): 283-287 (2004), DOI 10.1140/epja/i2003-10125-0 | systematic d(d,p)t screening survey: 58 samples spanning metals, insulators, semiconductors | deuterated metals, insulators, semiconductors, lanthanides | deuteron implantation / gas absorption per sample | low-energy deuteron beams versus a gaseous D2 reference | identical beam-energy class across all 58 samples | the authors report large screening in most metals, small (gas-like) values in insulators, semiconductors and lanthanides, periodic-table ordering of the effect, and suggest classical Debye-type plasma screening by quasi-free metallic electrons as a candidate mechanism |
| K. Czerski, A. Huke, P. Heide, G. Ruprecht (Hahn-Meitner-Institut Berlin, TU Berlin) | 2004 | Europhysics Letters 68 (3): 363-369 (2004), DOI 10.1209/epl/i2004-10209-3 | five-target screening study plus improved dielectric-function theory and extrapolation to room-temperature energies | carbon (amorphous), aluminum (AlD), zirconium (ZrD2), palladium (PdD0.2, deliberately implanted only to 0.2 stoichiometry to limit lattice defects), tantalum (TaD) | deuteron implantation at the listed stoichiometries | 5 to 60 keV D+ and D2+ beams | thick targets; angular-distribution-corrected yields | the authors report screening energies of minus 20 plus or minus 5 eV (C), 191 plus or minus 12 eV (Al), 295 plus or minus 7 eV (Zr), 296 plus or minus 15 eV (Pd), 302 plus or minus 13 eV (Ta); theory (polarization plus cohesion, 14 to 136 eV) tracks the material trend but sits about a factor 2 low; with moving target deuterons, a 220 eV effective screening fits the Jones-type neutron rates while the Fleischmann-Pons heat rate would demand about 620 eV |
| F. Raiola, B. Burchard, Z. Fulop, G. Gyurky and co-workers (LUNA Collaboration partners) | 2005 | Journal of Physics G: Nuclear and Particle Physics 31 (11), DOI 10.1088/0954-3899/31/11/002 | temperature-dependence study of d(d,p)t screening in metals | deuterated platinum and cobalt targets | deuteron implantation | low-energy deuteron beams; sample stage heated | platinum at 20 to 340 degrees C; cobalt at 20 and 200 degrees C | the authors report the temperature dependence of the measured screening energy in metallic hosts, the experimental handle on how thermal conditions modulate screening |
| A. Huke, K. Czerski, P. Heide, G. Ruprecht, N. Targosz, W. Zebrowski (TU Berlin, University of Szczecin, TRIUMF) | 2008 | Physical Review C 78: 015803 (2008), DOI 10.1103/PhysRevC.78.015803 (preprint arXiv:0805.4538) | new differential yield analysis method applied to deuteron-implanted metals; systematic study of surface and deuteron-density artifacts | zirconium, palladium, tantalum targets under multiple surface conditions | deuteron implantation, on-line density monitoring | 5 to 50 keV deuteron beams | varied target surface histories (four tantalum conditions) | the authors report zirconium 297 plus or minus 8 eV, palladium 313 plus or minus 2 eV, and tantalum spanning 213 to 462 eV depending on surface state; they show target surface contamination and deuteron-density dynamics can distort screening values, and they exclude the Debye-Hueckel model as the mechanism |
| A. Kowalska, K. Czerski, P. Horodek, K. Siemek and co-workers (University of Szczecin eLBRUS laboratory and partners) | 2023 | Materials 16 (18): 6255 (2023), DOI 10.3390/ma16186255 | positron annihilation spectroscopy (PAS) and X-ray diffraction (XRD) on deuteron-irradiated zirconium from the ultra-high vacuum (UHV) accelerator campaign | cold-rolled zirconium foils, deuteron plus carbon/oxygen ion implanted | deuteron irradiation producing vacancies and zirconium deuteride (ZrH1.5-phase) formation | 10 to 20 keV and 80 keV deuteron beams plus 200/240 keV C and O ions | UHV conditions; defect depth profiling to about 600 nm | the review section records the field situation: observed deuteron-deuteron screening energies of order 400 eV against about 100 eV theoretical, resolved toward theory in the atomically clean UHV zirconium experiment; cold-rolled palladium shows high screening while annealed palladium does not; cubic-structure titanium shows high screening while hexagonal-phase titanium shows small values; density functional theory (DFT) results allow up to nine hydrogen atoms trapped per zirconium vacancy |
Confirmed screening values, one line each
- Gas target (molecular D2 baseline): 25 plus or minus 5 eV (Greife 1995).
- Aluminum: 190 plus or minus 15 eV (Berlin 2001), 191 plus or minus 12 eV (Berlin 2004).
- Zirconium: 297 plus or minus 8 eV (Berlin 2001, confirmed 2008), 295 plus or minus 7 eV (Berlin 2004), but 80 plus or minus 20 eV class when the surface re-oxidizes.
- Palladium: 296 plus or minus 15 eV at PdD0.2 (Berlin 2004), 310 plus or minus 50 eV (Tohoku 2002), 313 plus or minus 2 eV (Berlin 2008), and 800 plus or minus 90 eV (LUNA, Physics Letters B 2002), the largest d(d,p)t value in the record.
- Tantalum: 322 plus or minus 15 eV (Berlin 2001), 302 plus or minus 13 eV (Berlin 2004), 309 plus or minus 12 eV (LUNA 2002), and 213 to 462 eV across four surface histories (Berlin 2008).
- Carbon (amorphous): minus 20 plus or minus 5 eV, effectively no screening, attributed to strong D-C chemical bonding.
- Insulators, semiconductors, lanthanides: gas-like small values (Raiola survey 2004).
- Field summary quoted in the 2023 Szczecin review: deuteron-deuteron screening of order 400 eV observed against about 100 eV theoretical, with atomically clean UHV targets pulling the value back toward theory.
Narrative
What the field established. Between 1995 and 2008 the Berlin, Bochum-LUNA and Tohoku groups turned electron screening in metals from an anomaly into a systematic material property. The bare-nucleus baseline is the 25 eV gas value; deuterated metals return screening potentials clustered near 300 eV for aluminum, zirconium, palladium and tantalum, with palladium reaching 800 plus or minus 90 eV in the LUNA measurement and amorphous carbon returning zero. The Czerski 2004 theory paper is the interpretive anchor: dielectric-function polarization plus ion cohesion reproduces the observed material ordering and gets the scale to within a factor of about 2, and the effective-screening extrapolation lets accelerator data be rolled down to room-temperature energies. The Huke 2008 Physical Review C paper then consolidated the campaign and, critically, cataloged the artifact channels: surface oxidation (zirconium drops from about 295 to about 80 eV when it re-oxidizes), sputter-cleaning reversals, and deuteron-density dynamics that can mimic a screening shift. The 2023 Szczecin work closes the loop on mechanisms by tying screening strength to the vacancy population and the hydrogen-trapping it enables.
The levers the record exposes. Three host variables move the screening number. Electron density: the Thomas-Fermi screening energy scales as the sixth root of electron density times the square root of the effective electron mass, so denser-electron, larger-effective-mass hosts screen more. Crystal structure: cubic-phase titanium screened high while hexagonal-phase titanium screened small in the same campaign, and the cubic face-centered metals palladium and nickel carry the largest confirmed values. Defects and vacancies: cold-rolled palladium screened high, annealed palladium did not, deuteron irradiation carves out vacancy distributions (depth profiles measured by PAS) that trap up to nine hydrogens apiece in zirconium, and atomically clean UHV surfaces pull the observed values back toward the theoretical ones. Temperature and surface chemistry modulate all of this, as the 2005 platinum-cobalt study and the oxidation record show.
Why this cluster carries the device program. The screening potential enters the deuteron-deuteron penetration factor as an energy shift: the rate scales roughly as the exponential of 31.29 times Ue divided by E to the power three halves (in keV units). At 1 keV deuteron energy a 300 eV screening potential multiplies the bare rate by about 1e4; at 0.5 keV by about 3e11; at 2 keV by about 27 (estimates from the standard formula). Screening alone does not make room-temperature fusion observable, and the concept brief says exactly that; what it does is set the multiplier that our piezoelectric gap fields (0.1 to 1 keV per deuteron) act on. The measured spread, from zero in carbon to 800 eV in palladium, is our host-material selection table.
Carry into device
- Host selection by confirmed screening value: palladium, tantalum and zirconium sit at the 300 eV class with the tightest error bars; palladium's 800 plus or minus 90 eV LUNA value, if transferable off the beam platform, is the single most valuable number in the field and our first test target. Titanium belongs on the list only in its cubic (hydride) phase.
- Defect engineering is a first-class lever: the record ties screening strength to cold work, vacancy population and deuteron trapping. Our shear-thickening suspension runs on crushed and milled powders, so it lives in the high-defect regime by construction; we should quantify vacancy densities on witness foils with PAS before and after mechanical excitation, and treat annealing as the negative control the record already provides.
- Surface discipline: oxide layers suppress measured screening (zirconium 295 versus 80 eV), yet the gas-loading cluster shows deliberate re-oxidation restores hydride energetics after aging. Specify oxide state per batch, load powders in deuterium gas before suspension, and log both.
- Electron density and effective mass are design variables we can compute: rank candidate hosts (palladium, nickel, zirconium, titanium, lanthanum-nickel hydride-forming alloys) by Thomas-Fermi screening estimates and effective electron mass before spending beam time; the 58-sample Raiola survey is the validation set for such a ranking.
- Beam-off discrimination is our structural advantage: the known artifact channel (deuteron-density dynamics in implanted targets) does not exist in a suspension device, where deuterons are born in the lattice and accelerated across gaps mechanically. Any signal we see is not that artifact class.
- Temperature mapping: screening varies measurably with host temperature (platinum 20 to 340 degrees C study); our device sweeps temperature during ultrasound and piezo drive, so witness-target screening should be characterized at the same temperatures as the device runs.
- Arithmetic to carry: 100 to 300 eV of screening multiplies deuteron-deuteron rates by 1e4 to 1e11 across the 0.5 to 1 keV window (estimate). Every volt we add across a piezo gap is worth more at lower deuteron energy, which fixes our optimization target: maximize gap field at the lowest credible gap crossing energy.