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We report on measuring techniques for neutrons that have been developed at the Physikalisch-Technische Bundesanstalt (PTB), the German National Metrology Institute. PTB has characterized radioactive sources used in the BOREXINO and XENON100 experiments. For the BOREXINO experiment, a {sup 228}Th gamma radiation source was required which would not emit more than 10 neutrons per second. The determination of the neutron emission rate of this specially designed {sup 228}Th source was challenging due to the low neutron emission rate and because the ratio of neutron to gamma radiation was expected to be extremely low, of the order of 10{sup −6}. For the XENON100 detector, PTB carried out a high accuracy measurement of the neutron emission rate of an AmBe source. PTB has also done measurements in underground laboratories. A two month measurement campaign with a set of {sup 3}He-filled proportional counters was carried out in PTB's former UDO underground laboratory at the Asse salt mine. The aim of the campaign was to determine the intrinsic background of detectors, which is needed for the analysis of data taken in lowintensity neutron fields. At a later time, PTB did a preliminary measurement of the neutron fluence rate at the underground laboratory Felsenkeller operatedmore » by VKTA. By taking into account data from UDO, Felsenkeller, and detector calibrations made at the PTB facility, it was possible to estimate the neutron fluence rate at the Felsenkeller underground laboratory.« less

Elastic scattering angular distribution measurements of 7Be+27Al system were performed at the laboratory energy of 15.6 MeV. The 7Be secondary beam was produced by the proton transfer reaction 3He(6Li,7Be) and impinged on 27Al and 197Au targets, using the Radioactive Ion Beam (RIB) facility, RIBRAS. The elastic angular distribution was obtained within the angular range of 150 - 800 at the center of mass frame. Optical model calculations have been performed using the Woods- Saxon form factors and the Sao Paulo potential to fit the experimental data. The total reaction cross section was derived.

The successful acceleration of an unpolarized Helium-3 beam by the AGS at BNL heralds the possibility of achieving polarized He-3 ions at RHIC. Assessing the level of polarization will be a challenge at high energy as the inelastic channels associated with He-3 scattering off a carbon target in the electromagnetic hadronic interference region may dilute expectations by comparison with the successful use of this method for proton polarimetry. The large anomalous magnetic moment of He-3 is helpful however, though the greater hadronic elastic cross section reduces the optimal analyzing power. Encouragement may be drawn from measurements indicating little high energy hadronic spin dependence.

Measurements on thermal conductivity of fluid helium-3 in the literature are abundant in the liquid phase, while almost no data are available in the gas phase except some at pressures not higher than 0.1 MPa. A quantum version of the principle of corresponding states is used to predict the thermal conductivity of gaseous helium-3 by using those of helium-4, hydrogen, neon and argon. An empirical equation is developed for the thermal conductivity of both the liquid and gas phases at temperatures from 3 mK to 300 K and pressures up to 20 MPa. Similar to other cryogenic fluids like nitrogen, a sharp peak of the thermal conductivity curve is observed at low pressures.

The 2H(3He,p3H)1H and 2H(3He,n3He)1H processes have been measured in quasi free kinematics to investigate for the first time the 2H(d,p)3H and 2H(d,n)3He reactions by means of the Trojan Horse Method. The 3He+d experiment was performed at 18 MeV, corresponding the a d-d energy range from 1.5 MeV down to 2 keV. This range overlaps with the relevant region for Standard Big Bang Nucleosynthesis as well as with the thermal energies of future fusion reactors and deuterium burning in the Pre Main Sequence phase of stellar evolution. This is the first pioneering experiment in quasi free regime where the charged spectator is detected. Both the energy dependence and the absolute value of the bare nucleus S(E) factors have been extracted for the first time. They deviate by more than 15% from available direct data with new S(0) values of 57.4±1.8 MeVb for 3H+p and 60.1±1.9 MeVb for 3He+n. None of the existing fitting curves is able to provide the correct slope of the new data in the full range, thus calling for a re...

In 1998, [2] pointed out the big difference for the S34(0) ('old' experimental data) when experimental results were grouped starting from the main two methods: S34(0) = 0.507(16)keVb for the direct capture and S34(0) = 0.572(26)keVb for the activation. Its importance for the Standard Solar Model was the reason to ask for new measurements to understand the discrepancy. 'New' results [4]solved this issue by equalizing the above values, but introduced a new situation to clarify: a discrepancy between the S34(E) variations for 'old' and 'new' data at higher energies than ECM = 1.0MeV. 'Old' theoretical models, used for extrapolating the S34(E) to the stellar energies, couldn't explain this new behavior. New experimental data [3, 5] was required, again, by theorists. We started this project with the main goal to clarify the situation. Here are the results.

Several reactions have been experimentally studied, including the 12N(d,n)13O and the ones induced by the 3He+12C entrance channel. The former was carried out at the CRIB facility of University of Tokyo, aiming to indirectly determine the astrophysical reaction rates of the 12N(p,γ)13O reaction. For the 3He+12C entrance channel, many excited states of several nuclei are populated and the angular distribution of each state is being analyzed.

The 2H(d,p)3H, 2H(d,n)3He, and 2H(d,γ)4He reactions at low energies are studied with realistic nucleon-nucleon interactions in an ab initio approach. The obtained astrophysical S-factors are all in very good agreement with experiment. The most important channels for both transfer and radiative capture are all found to dominate thanks to the tensor force.

We have measured the differential cross section for the γ3He→π+t reaction. This reaction was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Real photons produced with the Hall‐B bremsstrahlung tagging system in the energy range from 0.5 to 1.55 GeV were incident on a cryogenic liquid 3He target. The differential cross sections for the γ3He→π+t reaction were measured as a function of photon‐beam energy and pion‐scattering angle. Theoretical predictions to date cannot explain the large cross sections except at backward angles, showing that additional components must be added to the model.

ICRF is the primary auxiliary heating in C‐Mod where both H or 3He minority and mode conversion regimes are utilized. For transport analysis, the power deposition profile is critical and measuring the resulting fast ion distribution provides a direct means to constrain and validate ICRF simulations used to calculate power deposition. In mode conversion, measurement of the minority ion density, temperature, and velocity profiles is critical for the wave physics and may provide some insight into the fundamental physics of flow drive. Using active charge exchange, the He+1 4686A or H 6563A line is observed to find whether fast ion and relevant thermal ion measurements are practical. Results of these experiments yield fast ion and thermal ion measurements in D(He). A new analysis technique to extract information from high noise fast ion spectra is developed. A development path for improved D(3He) and D(H) is indicated.

The isovector spin monopole resonances (IVSMR) of the β+ type were observed for the first time in the 208Pb and 90Zr(t,3He) reactions at 300 MeV/u. The experiment was performed at the RI Beam Factory (RIBF) at RIKEN by using the newly‐constructed magnetic spectrometer SHARAQ. The double differential cross sections for the 208Pb and 90Zr(t,3He) reactions were obtained at the excitation energy of 0≤Ex≤70 MeV and the scattering angles of 0°≤θ≤3°. The monopole component was identified by making a difference between the zero‐degree and backward‐angle spectra. The signatures of the IVSMR are observed at an excitation energy of 12 MeV(20 MeV) in 208Pb(90Zr)(t,3He) reaction, which agrees fairly well with the theoretical predictions.

Gamow‐Teller (GT) transitions can be studied in both β decay and charge exchange (CE) reactions. If isospin is a good quantum number, then the Tz = −1→0 and Tz = +1→0 GT mirror transitions, are identical. Therefore, a comparison of the results from studies of β decay and CE should shed light on this assumption. Accordingly we have studied the β decay of the Tz = −1 fp‐shell nuclei, 54Ni, 50Fe, 46Cr, and 42Ti, produced in fragmentation and we have compared our results with the spectra from (3He, t) measurements on the mirror Tz = +1 target nuclei studied in high resolution at RCNP, Osaka. The β decay experiments were performed as part of the STOPPED beam RISING campaign at GSI.

The ground state hyperfine structure and other properties are calculated for muonic helium atoms (3He+2μ−e− or 4He+2μ−e−) with the use of some local properties of the wave functions in the domains where two particles are close to each other or far away. Simple wave functions incorporating these properties with one variational parameter is developed. The calculated values for hyperfine structure, energy and average interparticle distances in ground state are compared with the correlation function hyper‐spherical harmonic method and multibox variational approach. The obtained results are very close to the values calculated by mentioned methods, giving strong indications that the proposed wave functions provide relatively accurate values.

Thomas Jefferson National Accelerator Facility (Jefferson Lab) has become one of the premier facilities for the study of nucleon spin structure. Over the past two decades, several high precision measurements of the polarized structure functions g1(x,Q2) and g2(x,Q2) have been performed that have extensively covered the region between 0.02 and 5 GeV2. Spin moments have been formed from the measured structure functions. These proceedings will concentrate on experiment E97‐110, which was performed in Hall A to study the neutron and 3He spin structure at four‐momentum transfers squared (Q2) = 0.02 ‐ 0.26 GeV2. This range allows us to make a benchmark‐check of Chiral Perturbation Theory calculations. Previous results for the neutron spin polarizability, δLT , down to 0.1 GeV2 have shown significant disagreement with the calculations. Preliminary results on the generalized spin polarizabilities, γ0 and δLT , for the neutron were presented at the conference and will be discussed here.

The J‐PARC E15 experiment will be performed to search for the simplest kaonic nuclear bound state, KNN, by the in‐flight 3He(K−,N) reaction. The exclusive measurement can be performed by a simultaneous measurement of the missing mass using the primary neutron or proton, and the invariant mass via the expected decay, e.g. K−pp→Λp→pπ−p. an overview of the experiment and the preparation status are reported.

A dedicated one‐dimensional Time Projection Chamber (1D‐TPC) was designed and produced at IRMM to determine the 6Li(n,α)3H cross section in the 0.4–2.8 MeV energy range, aiming at 5% accuracy. The basic TPC components were a twin gridded ionisation chamber (GIC) with interwired electrodes and fast digitisation of the anode and cathode signals. The energy of both reaction products emitted from a thin 6LiF sample at the common TPC cathode was measured. A Kr(97%)CO2(3%) mixture was used as the detector gas at a pressure up to 3.5 bar. A 238U sample mounted on the cathode of an ionisation chamber without grid was used as the neutron flux monitor. Special care was taken to reduce the experimental sources of uncertainty. The beam‐monitor 238U sample was characterised at IRMM by low‐geometry α‐counting with an accuracy of 0.1%. A 6Li sample was produced at IRMM by vacuum evaporation of 6LiF onto transparent aluminium backing. The number of 6Li atoms will be measured via Thermal Neutron Depth Profiling with an ex...

COSY, a storage and cooler synchrotron, which is fed by an injector cyclotron, is operated at Forschungszentrum Julich (Germany). It provides phase space cooled polarized or unpolarized beams of protons and deuterons with momenta between 0.3 and 3.7 GeV/c for internal experiments and to external target stations. The major experimental facilities, used for the ongoing physics program, are ANKE and WASA (internal) and TOF (external). A new internal target station to investigate polarization build‐up by spin‐filtering (PAX) has recently been commissioned. COSY is the machine for hadron spin physics on a world‐wide scale, which is also used for tests in conjunction with plans to build a dedicated storage ring for electric dipole moment (EDM) measurements of proton, deuteron and 3He. In this contribution recent results as well as future plans are summarized.

Polarized 3He targets have been widely used in nuclear and particle physics experiments to study neutron structure in the spin degree of freedom, as most of the 3He spin is carried by the unpaired neutron. The Spin‐Exchange Optical Pumping (SEOP) process is used in Jefferson Lab Hall A to polarize its 3He target. In recent years, both the performance and corresponding polarimetry of such a target have been greatly improved. Several experiments recently carried out in Hall A have achieved record high figure of merit using this target.

The Jefferson Lab Experiment E05-102 "Measurement of A{sub x}' and A{sub z}' asymmetries in the quasi-elastic {sup 3}He(e,e'd) reaction" was performed in Hall A in 2009. The main physics motivation of the experiment was to investigate the effects of small components of the {sup 3}He ground-state wave-function by a simultaneous measurement of double-polarization asymmetries in quasi-elastic kinematics for three exclusive channels, (e,e'd), (e,e'p), and (e,e'n), at almost identical momentum transfers, as well as for (e,e'). This experiment will help map the spin structure of the {sup 3}He nucleus onto the picture of the "free" polarized neutron. As such, it is of great relevance to the polarized-neutron programs at Jefferson Lab and beyond.

We discuss the nuclear EMC effect with particular emphasis on recent data for light nuclei including 2H, 3He, 4He, 9Be, 12C and 14N. In order to verify the consistency of available data, we calculate the χ2 deviation between different data sets. We find a good agreement between the results from the NMC, SLAC E139, and HERMES experiments. However, our analysis indicates an overall normalization offset of about 2% in the data from the recent JLab E03‐103 experiment with respect to previous data for nuclei heavier than 3He. We also discuss the extraction of the neutron/proton structure function ratio F2n/F2p from the nuclear ratios 3He/2H and 2H/1H. Our analysis shows that the E03‐103 data on 3He/2H require a renormalization of about 3% in order to be consistent with the F2n/F2p ratio obtained from the NMC experiment. After such a renormalization, the 3He data from the E03‐103 data and HERMES experiments are in a good agreement. We also present a detailed comparison between data and model calculations, which...

Reduced uncertainty in the thermonuclear rate of the {sup 33}S(p,{gamma}){sup 34}Cl reaction would help to improve our understanding of nucleosynthesis in classical nova explosions. At present, models are generally in concordance with observations that nuclei up to roughly the calcium region may be produced in these explosive phenomena; better knowledge of this rate would help with the quantitative interpretation of nova observations over the S-Ca mass region, and contribute towards the firm establishment of a nucleosynthetic endpoint. As well, models find that the ejecta of nova explosions on massive oxygen-neon white dwarfs may contain as much as 150 times the solar abundance of {sup 33}S. This characteristic isotopic signature of a nova explosion could possibly be observed through the analysis of microscopic grains formed in the environment surrounding a nova and later embedded within primitive meteorites. An improved {sup 33}S(p,{gamma}){sup 34}Cl rate (the principal destruction mechanism for {sup 33}S in novae) would help to ensure a robust model prediction for the amount of {sup 33}S that may be produced. Finally, constraining this rate could confirm or rule out the decay of an isomeric state of {sup 34}Cl(E{sub x} = 146 keV, t{sub 1/2} = 32 m) as a source formore » observable gamma-rays from novae. We have performed several complementary experiments dedicated to improving our knowledge of the {sup 33}S(p,{gamma}){sup 34}Cl rate, using both indirect methods (measurement of the {sup 34}S({sup 3}He,t){sup 34}Cl and {sup 33}S({sup 3}He,d){sup 34}Cl reactions with the Munich Q3D spectrograph) and direct methods (in normal kinematics at CENPA, University of Washington, and in inverse kinematics with the DRAGON recoil mass separator at TRIUMF). Our results will be used with nova models to facilitate comparisons of model predictions with present and future nova observables.« less

The proton‐induced pre‐equilibrium process in the energy range of 100 to 160 MeV, which leads to emission of composite ejectiles such as 3He and α‐particles, is discussed. New cross section and analyzing power measurements for the (p,3He) reaction on 93Nb at an incident energy of 160 MeV are presented, and these are found to be in agreement with the prediction of a statistical multistep theoretical formulation. The observed quenching of the analyzing power is also reproduced well by the theory. The results are consistent with earlier work at lower incident energies and other nuclear species.

In the far past, it was not possible to accurately correct for the finite geometry and the finite sample size of a neutron scattering set‐up. The limited calculation power of the ancient computers as well as the lack of powerful Monte Carlo codes and the limitation in the data base available then prevented a complete simulation of the actual experiment. Using e.g. the Monte Carlo neutron transport code MCNPX [1], neutron scattering experiments can be simulated almost completely with a high degree of precision using a modern PC, which has a computing power that is ten thousand times that of a super computer of the early 1970s. Thus, (better) corrections can also be obtained easily for previous published data provided that these experiments are sufficiently well documented. Better knowledge of reference data (e.g. atomic mass, relativistic correction, and monitor cross sections) further contributes to data improvement. Elastic neutron scattering experiments from liquid samples of the helium isotopes perform...

Gamow‐Teller (GT) transitions can be studied in both β‐ decay and charge exchange(CE) reactions. If isospin is a good quantum number, then the Tz = −1→0 and Tz = +1→0 GT mirror transitions, are identical. Therefore, a comparison of the results from studies of β decay and CE should shed light on this assumption. Accordingly we have studied the β decay of the Tz = −1 fp‐shell nuclei, 54Ni, 50Fe, 46Cr, and 42Ti, produced in fragmentation and we have compared our results with the spectra from (3He, t) measurements on the mirror Tz = +1 target nuclei studied in high resolution at RCNP, Osaka. The experiments were performed as part of the STOPPED beam RISING campaign at GSI.

Searches for the neutron electric dipole moment (EDM) are motivated by their highly suppressed Standard Model value. The observation of a non‐zero signal in the next generation of experiments would point unambiguously to the existence of new physics beyond the Standard Model. Several ongoing efforts worldwide hold the potential for an up to two‐orders‐of‐magnitude improvement beyond the current upper limit on the neutron EDM of 2.9×10−6 e‐cm. In this talk, I review the basic measurement principles of neutron EDM searches, then discuss a new experiment to be carried out in the United States at the Spallation Neutron Source with ultracold neutrons and an in‐situ 3He “co‐magnetometer”.

The Trojan Horse Method (THM) was applied to the 3He+6Li interaction in order to investigate the quasi‐free 6Li(d,α)4He reaction. The experiment was performed at 17 MeV at the Cyclotron Institute of the Czech Academy of Science. The extracted 6Li(d,α)4He quasi‐free cross‐section was compared with the behavior of direct data. A good agreement between data sets shows up throughout the energy range investigated, providing a very important validity test of the pole approximation for the THM above the Coulomb barrier.

Experimental search for the low‐lying 7H resonance was performed in the d(8He,3He)7H reaction with a 8He beam at 42A MeV. No well‐pronounced peak of 7H was observed, but the spectrum has some peculiarities at ∼2 MeV and ∼10.5 MeV above the t+4 n threshold. The d(12Be,3He)11Li reaction simultaneously measured at 71A MeV showed the population of 11Li ground state with the c.m.s. cross section of ≈1 mb/sr.

Gamow‐Teller (GT) transitions can be studied in both β‐decay and charge exchange(CE) reactions. If isospin is a good quantum number, then the Tz = −1→0 and Tz = +1→0 GT mirror transitions, are identical. Therefore, a comparison of the results from studies of β decay and CE should shed light on this assumption. Accordingly we have studied the β decay of the Tz = −1 fp‐shell nuclei, 54Ni, 50Fe, 46Cr, and 42Ti, produced in fragmentation and we have compared our results with the spectra from (3He, t) measurements on the mirror Tz = +1 target nuclei studied in high resolution at RCNP, Osaka. The β‐decay experiments were performed as part of the STOPPED beam RISING campaign at GSI.

This paper present the current work on neutron detection in Soltan Institute for Nuclear Studies. Lately, we have focused our research on the development of new organic scintillators including liquid scintillators for neutron detection and associated measurements. We measured liquid scintillators (also 10B—doped for thermal neutron detection) 3He tubes, composites, etc. Response of the following detectors on thermal neutrons, fast neutrons and gamma radiation—the pulse shape discrimination (PSD)—has been mainly performed by means of a zero—crossing (ZC) method.

In the no‐core shell model (NCSM) framework, we calculate the 3He electric dipole moment (EDM) generated by parity‐ and time‐reversal violation in the nucleon‐nucleon interaction. While the results are somehow sensitive to the interaction model chosen for the strong two‐ and three‐body interactions, we demonstrate the pion‐exchange dominance to the EDM of 3He, if the coupling constants for π, ρ and ω‐exchanges are of comparable magnitude, as expected. Finally, our results suggest that a measurement of 3He EDM would be complementary to the currently planned neutron and deuteron experiments, and would constitute a powerful constraint to the models of the pion P‐ and T‐violating interactions.

Polarized {sup 3}He obtained from metastability exchange optical pumping is used for various double polarized experiments at the Mainz Microtron (MAMI). At the experimental area more than 70% initial target polarization is available. Besides a description of the target setup and its performance under electron beam conditions, the status of the polarized {sup 3}He target for the tagged photon beam at MAMI will be given.

Charge‐exchange reactions of (n, p) and (p, n) type at intermediate energies are a powerful tool for the study of nuclear matrix element in ββ decay. The present paper reviews some of the most recent experiments in this context. Here, the (n, p) type reactions are realized through (d, 2He), where 2He refers to two protons in a singlet 1S0 state and where both of these are momentum analyzed and detected by the same spectrometer and detector. These reactions have been developed and performed exclusively at KVI, Groningen (NL), using an incident deuteron energy of 183 MeV. Final state resolutions of about 100 keV have routinely been available. On the other hand, the (3He, t) reaction is of (p, n) type and was developed at the RCNP facility in Osaka (JP). Measurements with an unprecedented high resolution of 30 keV at incident energies of 420 MeV are now readily possible. Using both reaction types one can extract the Gamow‐Teller transition strengths B(GT+) and B(GT−), which define the two “legs” of the ββ decay matrix elements for the 2vββ decay The high resolution available in both reactions allows a detailed insight into the excitations of the intermediate odd‐odd nuclei and, as will be shown, some unexpected features are being unveiled.

Experiment E97‐110 was performed at the Thomas Jefferson National Accelerator Facility in Hall A to provide a precise measurement of the moments of the neutron and 3He spin structure functions. A longitudinally‐polarized electron beam was scattered from a longitudinally or transversely polarized 3He target. The extended Gerasimov‐Drell‐Hearn integral and other moments of the neutron and 3He spin structure functions were extracted at very low momentum transfers (0.02

The elastic scattering of spin half helium‐3 nuclei at small angles can show a sufficiently large analyzing power to enable the level of helion polarization to be evaluated. As the helion to a large extent inherits the polarization of its unpaired neutron the asymmetry observed in helion collisions can be transformed into a measurement of the polarization of its constituent neutron. Neutron polarimetry therefore relies upon understanding the spin dependence of the electromagnetic and hadronic interactions in the region of interference where there is an optimal analyzing power.

Experiment E97‐110 was performed at the Thomas Jefferson National Accelerator Facility to provide a precise measurement of the 3He spin structure functions at low Q2 from 0.02 to 0.3 [GeV/c]2. A longitudinally‐polarized electron beam was scattered from a longitudinally or transversely polarized 3He target. From these data, we have extracted moments of the neutron and 3He spin structure functions at very low momentum transfers. These data allow us to make a benchmark check of Chiral Perturbation Theory calculations in a region where they are expected to be valid. In these proceedings, the experimental details are discussed and preliminary results on the first moments of the g1 (x,Q2) and g2 (x,Q2) structure functions are presented.

The cluster structure of 7Li and 7Be has been investigated by the elastic‐transfer 4He(7Li,4He)7Li and 3He(7Be,3He)7Be reactions, respectively. Angular distribution for the elastic‐transfer of 7Li+4He has been measured in Sao Paulo at ECM = 9.67 MeV. Together with available elastic‐transfer angular distributions measured at other energies ranging from ECM = 2.29 to 32.13 MeV, a global optical model analysis has been performed. The measurement of the elastic‐transfer angular distribution at ELAB = 48.2 MeV for the 7Be+3He system is also described.

We present a device for spin‐exchange optical pumping system to produce large quantities of polarized noble gases for Magnetic Resonance Imaging (MRI). A method and design of apparatus for pumping the polarization of noble gases is described. The method and apparatus enable production, storage and usage of hyperpolarized noble gases for different purposes, including Magnetic Resonance Imaging of human and animal subjects. Magnetic imaging agents breathed into lungs can be observed by the radio waves of the MRI scanner and report back physical and functional information about lung’s health and desease. The technique known as spin exchange optical pumping is used. Nuclear magnetic resonance is implemented to measure the polarization of hyperpolarized gas. The cells prepared and sealed under high vacuum after handling Alkali metals into the cell and filling with the 3He‐N2 mixture. The cells could be refilled. The 3He reaches around 50% polarization in 5–15 hours.

In this paper we discuss the feasibility of fusion reactors based on D‐3He and D‐D fuel mixtures. The low reactivity of the D‐3He and D‐D fusion reactions and the large energy losses due to bremsstrahlung and synchrotron radiation at high plasma temperatures severely restricts the choice of fuel mixtures that can be brought to ignition. These fuel mixtures are extremely sensitive to impurities and to helium ash retention and they would require reactor conditions (plasma density, temperature, beta and energy confinement time) that are much more demanding than the requirements for D‐T. A reactor burning D‐3He or D‐D would be far beyond the most optimistic extrapolations of known magnetic confinement schemes, it would have problems with sustainable fuel supplies and it would produce substantial numbers of neutrons. Our conclusion is that these fuels cannot be considered as realistic alternatives to D‐T.

Already long time ago the shape of the electron spectrum in β‐decays of 3H and 187Re has been recognized as an important tool for understanding of neutrino masses. The sensitivity of KATRIN (in preparation, tritium β‐decay) and the MARE (under consideration, 187Re β‐decay) experiments to neutrino mass will reach the sub eV domain. In view of this experimental progress there is a request for a highly accurate theoretical description of the electron endpoint spectra. By taking the advantage of the elementary particle treatment of 3H and 3He the relativistic form for β‐decay endpoint spectrum of tritium is obtained by taking into account also the effect of nuclear recoil. Further, the currently unknown shape of the electron spectrum for the β‐decay of 187Re is presented. It is found that the first forbidden 187Re(5/2+)→187Os(1/2−)β‐decay transition is accompanied with emission of mostly p3/2‐state electrons.

The ICRF mode conversion regime provides the effective local electron heating. The efficiency of the mode conversion could be enhanced due to the interference between the reflected waves [1]. The 1D theoretical model is presented for the case of two ion‐ion hybrid resonances in the plasma. The role of the carbon impurities in the inverted ICRF (3He)H scenario is studied. The optimal range of the helium and carbon concentrations for the enhanced mode conversion is estimated.

The roles of fusion products in diagnosing plasmas are quite diversified and rich in scientific content. From the early days to the new frontier of burning plasmas, the study of fusion products has allowed a deeper understanding of the physics found in these plasmas, spanning all configurations, in both magnetic and inertial confinement. In many early experiments, the measurement of plasma performance was based almost entirely on neutron yield measurements. Since then, the capability to measure fusion products has grown tremendously, and many new measuring techniques have been successfully tested and used in experiments. The first role is based on single‐particle diagnosis, which can yield important information on performance, confinement, source and current profiles, plasma fluctuations, effects of ripples, MHD mode structure, etc. The second role, which has expanded tremendously in the last few years, includes the diagnosis of collective effects, which can yield additional information on instabilities, ...

We discuss results and future plans for low‐energy reactions that play an important role in current nuclear astrophysics research and that happen to concentrate around the region of A = 7. The 7Be(p,γ)8B and the 3He(4He,γ)7Be reactions are crucial for understanding the solar‐neutrino oscillations phenomenon and the latter one plays a central role in the issue of cosmic 7Li abundance and Big‐Bang Nucleosynthesis. The electron‐capture (EC) decay rate of 7Be in metallic Cu host and the β−‐decay rate of 198Au in the host alloy Al‐Au have been measured simultaneously at several temperatures, ranging from 0.350 K to 293 K. The resulting null temperature dependence is discussed in terms of the inadequacy of the often‐used Debye‐Huckel model for such measurements.

The level density and radiative strength function for 146,147Sm and 163,164Dy have been extracted from primary γ spectra using the Oslo method. As one approaches the closed N = 82 neutron shell, the structures in the level density become more pronounced due to shell effects. The experimental level densities can be used to explore thermodynamic properties of the nucleus within the microcanonical ensemble. Pygmy resonances, which are based on the scissors mode and seen in deformed rare‐earth nuclei, are not observed in near‐spherical 146,147Sm, as expected. Pygmy resonances in 163,164Dy were studied after 3He‐induced reactions and their width was found to be twice as wide as compared to results reported after neutron‐capture reactions.

Gamow‐Teller (GT) transitions starting from unstable pf‐shell nuclei play important roles in neutrino‐induced reactions that happen under the extremely high temperature conditions in core‐collapse (type II) supernovae. In the β decay, it is difficult to obtain GT strengths B(GT) to higher excited states, but accurate half‐lives can be measured. On the other hand, high‐resolution (3He,t) charge‐exchange reactions at 0° and at 420 MeV yield cross‐sections, that are proportional to B(GT) values, for individual transitions up to high excitation. Assuming isospin symmetry, we performed a unique analysis to determine absolute B(GT) values for the Tz = ±1→0 analogous GT transitions. Further β‐decay studies for unstable pf‐shell nuclei to obtain accurate half‐lives and feeding ratios are in progress.

The modification of structure functions in nuclei (the EMC effect) has been the focus of intense experimental and theoretical study since the original observation in 1983. The EMC effect unequivocally demonstrates that quark distributions in nuclei are not simply the incoherent sum of the nucleon quark distributions. However, progress in understanding the root cause of these modifications has been hampered by the complexity of nuclear structure, making it difficult to disentangle the “conventional” nuclear effects of Fermi motion and binding from true medium modifications to nucleon structure. Experiment E03—103 at Jefferson Lab made measurements of nuclear structure function ratios from few—body nuclei (3He and 4He) to deuterium, where the nuclear structure is well known, and for a range of nuclei, A = 3 to 197, at large x, where effects from Fermi motion and binding dominate.

Hard deuteron photodisintegration has been investigated for 20 years, as its cross section follows the constituent counting rule and it provides insight into the interplay between hadronic and quark‐gluon degrees of freedom in high‐momentum transfer exclusive reactions. We have now measured for the first time hard pp‐pair disintegration in the reaction γ 3He→pp+n, using kinematics corresponding to a spectator neutron. Cross sections were measured for 90° c.m. at 8 beam energies, from 0.8 to 4.7 GeV. Preliminary results will be presented and compared to the hard deuteron photodisintegration data.

High resolution measurements using the (3He,n) reaction are used to determine excitation energies of astrophysically important states. Further, spins can be assigned to these states by comparing the measured differential cross sections to Hauser‐Feshbach cross sections. The astrophysical reaction rates are then calculated using the experimental values. Reference [1] is an example of such measurements.Absolute values of the astrophysical S factors and cross sections are calculated from measurements using the (d,n) reaction at low incident energies. Reference [2] is an example of such measurements.

The talk will be mainly devoted to the measurement of the cross section of the 3He(alpha,gamma)7Be reaction which belongs to the p-p chain. Actually, solar neutrino fluxes depend both on astrophysical and on nuclear physics inputs, namely on the cross sections of the reactions responsible for neutrino production inside the Solar core. While the flux of solar 8B neutrinos has been recently measured at Superkamiokande with a 3.5% uncertainty and a precise measurement of 7Be neutrino flux is foreseen in the next future, the predicted fluxes are still affected by larger errors. The largest nuclear physics uncertainty to determine the fluxes of 8B and 7Be neutrinos comes from the 3He(alpha,gamma)7Be reaction. The uncertainty on its S-factor is due to an average discrepancy in results obtained using two different experimental approaches: the detection of the delayed gamma rays from 7Be decay and the measurement of the prompt gamma emission. The LUNA Collaboration has performed a new high precision experiment with both techniques at the same time. Thanks to the low background conditions of the Gran Sasso LUNA accelerator facility, the cross section has been measured down to 93 keV, the lowest interaction energy ever reached. The S-factors from the two methods do not show any discrepancy within the experimental errors. An extrapolated S(0) = 0.560±0.017 keV barn is obtained. Moreover, branching ratios between the two prompt gamma -transitions have been measured with 3\u20138% accuracy. Recently, the LUNA Collaboration has presented to the Scientific Board of Gran Sasso Laboratory its experimental program for the next five years based on the existing 400 kV accelerator facility. A Letter of Intent addressing the possibility to install a 3 MV machine at Gran Sasso has also been submitted to the Board. The LUNA scientific programs with both the 400 kV and 3 MV accelerator facilities will be illustrated in the final part of the talk.

We have studied the properties of the unbound isotope of helium 7He, using the 2H(8Li,3He)7He reaction. When combined with prior measurements of the 2H(6He,p)7He reaction the data present a consistent picture for the low‐lying excited states of 7He, specifically the negative parity sequence 3/2− (ground state) 1/2− (first‐excited) and 5/2− (second‐excited). The shapes but not the absolute magnitudes of the angular distributions are reproduced by ab‐initio theory coupled with a DWBA reaction framework.

Recent progress on the solution of ab initio three‐ and four‐nucleon scattering equations in momentum space that include the correct treatment of the Coulomb interaction is reviewed; results for specific observables in reactions initiated by p+d, p+3He and n+3He indicate that the inclusion of the Coulomb interaction is paramount to validate two‐ and three‐nucleon force models. Three‐ and four‐nucleon force effects in 4He binding energy and four‐nucleon scattering observables are studied for the first time. The effect of the four‐nucleon force is found to be much smaller than the effect of the three‐nucleon force.