Nuclear astrophysics with radioactive ions at FAIR

The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes

Etude de l'emission proton et de deux protons dans les noyaux légers déficients en neutrons de la région A=20

Proton and two proton emission from light neutron deficient nuclei around A=20 have been studied. A radioactive beam of 18Ne, 17F and 20Mg, produced at the Grand Accélérateur National d'Ions Lourds by fragmentation of a 24Mg primary beam at 95MeV/A, bombarded a 9Be target to form unbound states. Proton(s) and nuclei from the decay were detected respectively in the MUST array and the SPEG spectrometer. From energy and angle measurements, the invariant mass of the decaying nucleus could be reconstructed. Double coincidence events between a proton and 17F, 16O, 15O, 14O and 18Ne were registered to obtain excitation energy spectra of 18Ne, 17F, 16F, 15F et 19Na. Generally, the masses measures are in agreement with previous experiments. In the case of 18Ne, excitation energy and angular distributions agree well with the predictions of a break up model calculation. From 17Ne proton coincidences, a first experimental measurement of the ground state mass excess of 18Na has been obtained and yields 24,19(0,15)MeV. Two proton emission from 17Ne and 18Ne excited states and the 19Mg ground state was studied through triple coincidences between two proton and 15O, 16O and 17Ne respectively. In the first case, the proton-proton relative angle distribution in the center of mass has been compared with model calculation. Sequential emission from excited states of 17Ne, above the proton emission threshold, through 16F is dominant but a 2He decay channel could not be excluded. No 2He emission from the 1,288MeV 17Ne state, or from the 6,15MeV 18Ne state has been observed. Only one coincidence event between 17Ne and two proton was registered, the value of the one neutron stripping reaction cross section of 20Mg being much lower than predicted.L'émission proton et de deux protons par des noyaux légers, déficients en neutrons, dans la région de masse A=20 a été étudiée. Un faisceau radioactif, constitué de 18Ne, 17F et de 20Mg a été produit au Grand Accélérateur National d'Ions Lourds, par fragmentation d'un faisceau primaire de 24Mg à 95MeV/A, et bombardait une cible de 9Be afin de former des états non liés. Le(s) proton(s) et le noyau issus de la décroissance étaient détectés dans l'ensemble MUST et le spectromètre SPEG, leurs énergies et angles d'émission mesurés pour reconstruire la masse invariante du noyau père. Les événements de coïncidence double entre un proton et les noyaux 17F, 16O, 15O, 14O et 18Ne ont été étudiés pour reconstruire les spectres en énergie d'excitation de 18Ne, 17F, 16F, 15F et 19Na. Les masses mesurées sont généralement en bon accord avec les résultats obtenus lors de précédentes expériences. Pour le noyau 18Ne, les distributions angulaires et en énergie d'excitation sont en bon accord avec un modèle de break up. A partir des coïncidences entre un proton et 17Ne, une première mesure expérimentale de l'excès de masse de l'état fondamental de 18Na donne 24,19(0,15)MeV. L'émission de deux protons depuis des états excités de 17Ne et 18Ne, ainsi que depuis l'état fondamental de 19Mg, a été étudiée à partir des événements de coïncidences entre deux protons et respectivement 15O, 16O et 17Ne. Dans le premier cas, la distribution en angle relatif des deux protons dans le centre de masse a été comparée aux résultats de simulation. L'émission séquentielle depuis un état excité de 17Ne, au-dessus du seuil d'émission proton, via 16F, domine mais une contribution d'émission 2He ne peut pas être exclue. Aucune émission 2He depuis l'état à 1,288MeV de 17Ne ni depuis celui à 6,15MeV dans 18Ne, n'a été observée. Un seul événement de coïncidence entre 17Ne et deux protons a pu être enregistré car la section efficace de la réaction de stripping d'un neutron de 20Mg est plus faible que prévu

LISA AIVT Optical Ground Support Equipement technology developments

International audienceThe LISA space interferometer aims at GW detection with »3x10-20/√Hz strain sensitivity, resulting in a displacement sensitivity of 11pm/√Hz over a path length of 2.5x109 m in the frequency range from 3x10-5 to 1 Hz.The LISA France Collaboration is in charge of the ground optical tests of the MOSA (Moving Optical Sub-Assembly), including the Optical Bench, Telescope and Gravitational Reference Sensor. Special check-out equipment is required, such as the Far-Field Optical Ground Support Equipment aiming at measuring the Tilt-To-Length coupling coefficient between angular residual beam jitter and longitudinal path length. The FF-OGSE simulates the incoming jittering beam and measures the associated longitudinal path length change.We present two prototypes – the Zerodur InterFerOmeter and the TTL-OB - that will demonstrate the optical performance, the functional tests, the limits on sensitivity and the precision of the path length measurements achievable on-ground. These two benches are the first part of the design and specification for the FF-OGSE.The Stray Light OGSE aims at stray light characterization in the integrated MOSA. It measures and identifies, separately, the different sources of stray light through the measurement of the corresponding fringe patterns while scanning the laser’s optical frequency

LISA AIVT Optical Ground Support Equipement technology developments

International audienceThe LISA space interferometer aims at GW detection with »3x10-20/√Hz strain sensitivity, resulting in a displacement sensitivity of 11pm/√Hz over a path length of 2.5x109 m in the frequency range from 3x10-5 to 1 Hz.The LISA France Collaboration is in charge of the ground optical tests of the MOSA (Moving Optical Sub-Assembly), including the Optical Bench, Telescope and Gravitational Reference Sensor. Special check-out equipment is required, such as the Far-Field Optical Ground Support Equipment aiming at measuring the Tilt-To-Length coupling coefficient between angular residual beam jitter and longitudinal path length. The FF-OGSE simulates the incoming jittering beam and measures the associated longitudinal path length change.We present two prototypes – the Zerodur InterFerOmeter and the TTL-OB - that will demonstrate the optical performance, the functional tests, the limits on sensitivity and the precision of the path length measurements achievable on-ground. These two benches are the first part of the design and specification for the FF-OGSE.The Stray Light OGSE aims at stray light characterization in the integrated MOSA. It measures and identifies, separately, the different sources of stray light through the measurement of the corresponding fringe patterns while scanning the laser’s optical frequency

LISA AIVT Optical Ground Support Equipement technology developments

International audienceThe LISA space interferometer aims at GW detection with »3x10-20/√Hz strain sensitivity, resulting in a displacement sensitivity of 11pm/√Hz over a path length of 2.5x109 m in the frequency range from 3x10-5 to 1 Hz.The LISA France Collaboration is in charge of the ground optical tests of the MOSA (Moving Optical Sub-Assembly), including the Optical Bench, Telescope and Gravitational Reference Sensor. Special check-out equipment is required, such as the Far-Field Optical Ground Support Equipment aiming at measuring the Tilt-To-Length coupling coefficient between angular residual beam jitter and longitudinal path length. The FF-OGSE simulates the incoming jittering beam and measures the associated longitudinal path length change.We present two prototypes – the Zerodur InterFerOmeter and the TTL-OB - that will demonstrate the optical performance, the functional tests, the limits on sensitivity and the precision of the path length measurements achievable on-ground. These two benches are the first part of the design and specification for the FF-OGSE.The Stray Light OGSE aims at stray light characterization in the integrated MOSA. It measures and identifies, separately, the different sources of stray light through the measurement of the corresponding fringe patterns while scanning the laser’s optical frequency

LISA AIVT Optical Ground Support Equipement technology developments

International audienceThe LISA space interferometer aims at GW detection with »3x10-20/√Hz strain sensitivity, resulting in a displacement sensitivity of 11pm/√Hz over a path length of 2.5x109 m in the frequency range from 3x10-5 to 1 Hz.The LISA France Collaboration is in charge of the ground optical tests of the MOSA (Moving Optical Sub-Assembly), including the Optical Bench, Telescope and Gravitational Reference Sensor. Special check-out equipment is required, such as the Far-Field Optical Ground Support Equipment aiming at measuring the Tilt-To-Length coupling coefficient between angular residual beam jitter and longitudinal path length. The FF-OGSE simulates the incoming jittering beam and measures the associated longitudinal path length change.We present two prototypes – the Zerodur InterFerOmeter and the TTL-OB - that will demonstrate the optical performance, the functional tests, the limits on sensitivity and the precision of the path length measurements achievable on-ground. These two benches are the first part of the design and specification for the FF-OGSE.The Stray Light OGSE aims at stray light characterization in the integrated MOSA. It measures and identifies, separately, the different sources of stray light through the measurement of the corresponding fringe patterns while scanning the laser’s optical frequency

LISA AIVT Optical Ground Support Equipement technology developments

International audienceThe LISA space interferometer aims at GW detection with »3x10-20/√Hz strain sensitivity, resulting in a displacement sensitivity of 11pm/√Hz over a path length of 2.5x109 m in the frequency range from 3x10-5 to 1 Hz.The LISA France Collaboration is in charge of the ground optical tests of the MOSA (Moving Optical Sub-Assembly), including the Optical Bench, Telescope and Gravitational Reference Sensor. Special check-out equipment is required, such as the Far-Field Optical Ground Support Equipment aiming at measuring the Tilt-To-Length coupling coefficient between angular residual beam jitter and longitudinal path length. The FF-OGSE simulates the incoming jittering beam and measures the associated longitudinal path length change.We present two prototypes – the Zerodur InterFerOmeter and the TTL-OB - that will demonstrate the optical performance, the functional tests, the limits on sensitivity and the precision of the path length measurements achievable on-ground. These two benches are the first part of the design and specification for the FF-OGSE.The Stray Light OGSE aims at stray light characterization in the integrated MOSA. It measures and identifies, separately, the different sources of stray light through the measurement of the corresponding fringe patterns while scanning the laser’s optical frequency

Nuclear astrophysics with radioactive ions at FAIR

The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes

Nuclear astrophysics with radioactive ions at FAIR

The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes