Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Measurements of an ablator-gas atomic mix in indirectly driven implosions at the National Ignition Facility

We present the first results from an experimental campaign to measure the atomic ablator-gas mix in the deceleration phase of gas-filled capsule implosions on the National Ignition Facility. Plastic capsules containing CD layers were filled with tritium gas; as the reactants are initially separated, DT fusion yield provides a direct measure of the atomic mix of ablator into the hot spot gas. Capsules were imploded with x rays generated in hohlraums with peak radiation temperatures of ∼294  eV. While the TT fusion reaction probes conditions in the central part (core) of the implosion hot spot, the DT reaction probes a mixed region on the outer part of the hot spot near the ablator-hot-spot interface. Experimental data were used to develop and validate the atomic-mix model used in two-dimensional simulations.

Measurement of the T + T neutron spectrum using the national ignition facility

Neutron time-of-flight spectra from inertial confinement fusion experiments with tritium-filled targets have been measured at the National Ignition Facility. These spectra represent a significant improvement in energy resolution and statistics over previous measurements, and afford the first definitive observation of a peak resulting from sequential decay through the ground state of (5)He at low reaction energies E(c.m.) 100 </~ keV. To describe the spectrum, we have developed an R-matrix model that accounts for interferences from fermion symmetry and intermediate states, and show these effects to be non-negligible. We also find the spectrum can be described by sequential decay through ℓ=1 states in (5)He, which differs from previous interpretations.

Hohlraum-driven ignitionlike double-shell implosions on the omega laser facility

High-convergence ignitionlike double-shell implosion experiments have been performed on the Omega laser facility [T. R. Boehly, Opt. Commun. 133, 495 (1997)] using cylindrical gold hohlraums with 40 drive beams. Repeatable, dominant primary (2.45 MeV) neutron production from the mix-susceptible compressional phase of a double-shell implosion, using fall-line design optimization and exacting fabrication standards, is experimentally inferred from time-resolved core x-ray imaging. Effective control of fuel-pusher mix during final compression is essential for achieving noncryogenic ignition with double-shell targets on the National Ignition Facility [Paisner, Laser Focus World 30, 75 (1994)].

Jacobsen syndrome: report of a patient with severe eye anomalies, growth hormone deficiency, and hypothyroidism associated with deletion 11 (q23q25) and review of 52 cases

We have evaluated a patient with Jacobsen syndrome. The patient presented with growth retardation, hypotonia, trigonocephaly, telecanthus, downward slanting palpebral fissures, bilateral inferior colobomas (of the iris, choroid, and retina), hydrocephalus, central nervous system (CNS) abnormalities, and an endocardial cushion defect, features commonly seen in Jacobsen syndrome. Endocrine evaluation showed growth hormone deficiency and central hypothyroidism. Chromosome analysis showed a 46,XX,del(11)(q23q25) de novo karyotype. Cytogenetically, the deletion appeared to include most of bands 11q23 and q24 and a portion of q25. Using chromosome specific paint probe, a combination of chromosome 11 centromere, telomere, and region specific cosmid probes from 11q14.1-14.3, 11q23.3, and 11q24.1, we have localised the deletion breakpoint to q24.1. Phenotype-karyotype correlation of patients with Jacobsen syndrome and specific deletions of chromosome 11q has enabled us to suggest that the critical region for this syndrome lies in close proximity to cytogenetic band 11q24. Although growth retardation is a consistent finding in 11q deletion syndrome, the presence of hypothalamic-pituitary hormone deficiency has not been reported previously.

Diagnosis of trisomy 18 using spontaneously dividing cells from fetal umbilical cord blood: a novel approach for rapid late second and third trimester prenatal diagnosis

Cytogenetic methodology recently developed by us allows spontaneously dividing cells in fetal cord blood to be used for rapid (24 hours) chromosome analysis. We utilized this methodology to diagnose trisomy 18 and facilitate clinical management in a 32-week pregnancy characterized by multiple fetal anomalies and intrauterine growth retardation.

Rapid chromosome analysis with the use of spontaneously dividing cells derived from umbilical cord blood (fetal and neonatal)

An accurate and reproducible method to obtain high-quality metaphases within 24 hours has been developed. Preparations can be derived from cord blood samples obtained either at delivery or by percutaneous umbilical blood sampling. Mitogens are not required. Rapid cytogenetic analysis can facilitate management of pregnancies characterized by malformations or intrauterine growth retardation.

Growth retardation, alopecia, pseudo-anodontia, and optic atrophy--the GAPO syndrome: report of a patient and review of the literature

The GAPO syndrome is a rare but distinct autosomal-recessive disorder. The term GAPO is an acronym for the manifestations of Growth retardation. Alopecia, Pseudo- anodontia (failure of tooth eruption), and progressive Optic atrophy. We are aware of five other published patients. All have a strikingly similar appearance. This, along with other distinct manifestations, should allow clear differentiation from other causes of growth retardation. The hypothesis of autosomal-recessive inheritance is based on parental consanguinity and affected sibs in several cases.

Ga-67 cardiac uptake

A case of positive Ga-67 image due to tuberculous pericarditis is presented. The pattern and distribution of the uptake suggested that the concentration of the activity was mainly in the inflamed pericardium. The known causes of Ga-67 cardiac uptake were reviewed, and a differential diagnosis is given.

Hyperpipecolic acidemia. Occurrence in an infant with clinical findings of the cerebrohepatorenal (Zellweger) syndrome

An infant with clinical presentation of the cerebrohepatorenal syndrome (CHRS) of Zellweger was found to have increased plasma and urinary concentrations of pipecolic acid. When given a loading dose of DL-pipecolic acid hydrochloride, she showed a reduced clearance rate for that acid. Piperidine, delta 6-piperidine-2-carboxylic acid, and alpha-aminoadipic acid were not detected in plasma or urine. Her response to a lysine load was comparable to that of controls. These data provide further evidence of the connection between hyperpipecolic acidemia and CHRS.

Transient leukemoid reaction and trisomy 21 mosaicism in a phenotypically normal newborn

Transient leukemoid reactions that resemble acute leukemia have been well described for infants with trisomy 21 (Down syndrome). We report a phenotypically normal 3-day-old boy with hepatosplenomegaly, leukocytosis, and circulating myeloblasts. On chromosome analysis, trisomy 21 was found in all blood and bone marrow cells. However, only 4% of cultured skin fibroblasts were trisomic and the other 96% were normal, thus indicating mosaicism. Without treatment, the leukocyte count gradually returned to normal and the organomegaly diminished. Subsequently, chromosome analysis of blood and bone marrow disclosed a predominance of cells with a normal karyotype. These findings suggest that mosaicism could be responsible for the transient leukemoid reactions in some newborns--i.e., the trisomic cells may temporarily gain a proliferative advantage over the normal cells, perhaps by inhibiting their growth. Serial cytogenetic studies, as well as chromosome analysis of more than one tissue, may help to distinguish transient leukemoid reactions from acute leukemia in infants.

Duplication 6q syndrome

Duplication (partial trisomy) of the long arm of chromosome 6 has been described in 5 children [Robertson et al, 1975, Chen et al, 1976, Clark, 1977]. We wish to report here an additional case due to a familial translocation in which the proband's karyotype is 46,XX,der(3),rcp(3;6)(p25;q21)mat. The phenotypes of the 6 children with duplication 6q are strikingly similar. Each child has duplication involving approximately the distal 1/3 to 1/2 of the long arm of chromosome 6. Distinctive features present in all 6 children include microcephaly, acrocephaly, prominent forehead, flat facial profile, depressed nasal bridge, flat malar areas, "carp" mouth, micrognathia and mental retardation. The phenotype of the duplication 6q syndrome is distinctive enough to be clinically recognizable.

Sialidase (alpha-n-acetyl neuraminidase) deficiency: the enzyme defect in an adult with macular cherry-red spots and myoclonus without dementia

A 31-year-old male is described who has macular cherry-red spots, increased deep tendon reflexes and and myoclonus without dementia. An older brother died at age 33 of a disease with similar symptomatology. Homogenates of cultured fibroblasts from the patient exhibited 2.6, 8.1 and 12.4% of normal mean sialidase (neuraminidase, N-acetyl-neuraminosyl glycohydrolase, EC 3.21.18) activity, respectively, against 2-(3'-methoxyphenyl)-N-acetyl-alpha-neuraminic acid, N-acetyl-neuramin-lactose and fetuin. Activities of 14 other lysosomal enzymes were within the range of normal control fibroblasts. The sialidase activities in fibroblasts from the patient's parents and children were 30 to 67% of normal. It is concluded that this is the first proven case of a new autosomal recessive disorder resulting in cherry-red spots, myoclonus and a sialidase deficiency.

The Dubowitz syndrome

The Dubowitz syndrome is an autosomal recessive condition of intrauterine growth retardation, postnatal growth retardation, microcephaly, characteristic facial appearance, high-pitched hoarse voice, and borderline intelligence or mild mental retardation. Cleft palate may occur as well as hypospadias, cryptorchidism in affected males, and mild limb defects. The 13 cases reported in the European literature and eight personally examined patients are reviewed.