Low-energy investigations on rare ion beams are often limited by the available intensity and purity of the ion species in focus. Here, we present the first application of a technique that combines ...in-flight production at relativistic energies with subsequent secondary beam storage, accumulation and finally deceleration to the energy of interest. Using the FRS and ESR facilities at GSI, this scheme was pioneered to provide a secondary beam of 118Te52+ for the measurement of nuclear proton-capture at energies of 6 and 7 MeV/u. The technique provided stored beam intensities of about 106 ions at high purity and brilliance, representing a major step towards low-energy nuclear physics studies using rare ion beams.
Abstract
The matter radius of the doubly magic
$$^{56}$$
56
Ni was extracted from a measurement of the differential cross section by employing, for the first time, elastic proton scattering in ...inverse kinematics with a radioactive beam at
$$E_{kin}=390.2$$
E
kin
=
390.2
MeV/nucleon circulating in a storage ring and passing an internal hydrogen gas-jet target with a revolution frequency of around 2 MHz. The novel experimental scheme is based on UHV-compatible Si detectors operated as active vacuum windows, which were implemented in the ESR storage ring at GSI. A matter radius
$$<r_{m}^{2}>^{1/2}=3.74^{+0.03}_{-0.06}$$
<
r
m
2
>
1
/
2
=
3
.
74
-
0.06
+
0.03
fm was extracted for the doubly-magic self-conjugate nucleus
$$^{56}$$
56
Ni.
Neutron-induced reaction cross sections of unstable nuclei are essential for understanding the synthesis of heavy elements in stars and for applications in nuclear technology. However, their ...measurement is very complicated due to the radioactivity of the targets involved. We propose to circumvent this problem by using the surrogate reaction method in inverse kinematics, where the nucleus formed in the neutron- induced reaction of interest is produced by a reaction involving a radioactive heavy-ion beam and a stable, light target nucleus. The probabilities as a function of the compound-nucleus excitation energy for
γ
-ray emission, neutron emission and fission, which can be measured with the surrogate reaction, are particularly useful to constrain model parameters and to obtain more accurate predictions of the neutron-induced reaction cross sections of interest. Yet, the full development of the surrogate method is hampered by numerous long- standing target issues, which can be solved by combining surrogate reactions with the unique and largely unexplored possibilities at heavy-ion storage rings. In this contribution, we describe the developments we are carrying out to measure for the first time simultaneously
γ
-ray emission, neutron emission and fission probabilities at the storage rings of the GSI/FAIR facility. In particular, we will present the first results of the proof of principle experiment, which we performed in June 2022 at the Experimental Storage Ring (ESR) of GSI/FAIR.
A new technique developed for measuring nuclear reactions at low momentum transfer with stored beams in inverse kinematics was successfully used to study isoscalar giant resonances. The experiment ...was carried out at the experimental heavy-ion storage ring (ESR) at the GSI facility using a stored 58Ni beam at 100 MeV/u and an internal helium gas-jet target. In these measurements, inelastically scattered α-recoils at very forward center-of-mass angles (θcm≤1.5°) were detected with a dedicated setup, including ultra-high vacuum compatible detectors. Experimental results indicate a dominant contribution of the isoscalar giant monopole resonance at this very forward angular range. It was found that the monopole contribution exhausts 79−11+12% of the energy-weighted sum rule (EWSR), which agrees with measurements performed in normal kinematics. This opens up the opportunity to investigate the giant resonances in a large domain of unstable and exotic nuclei in the near future. It is a fundamental milestone towards new nuclear reaction studies with stored ion beams.
Abstract
Determining the cross sections of neutron-induced reactions on short-lived nuclei is imperative to rate calculations in stellar nucleosynthesis and applications of nuclear physics. It is ...also an immense experimental challenge due to the radioactivity of the targets involved. Our goal is to circumvent this obstacle by using surrogate reactions in inverse kinematics at the heavy-ion storage rings of GSI/FAIR. We present here preliminary results from the first proof of principle experiment, where a beam of
208
Pb impinged on a H
2
gas jet target in the Experimental Storage Ring (ESR).
A heavy-ion detector was developed for decay studies in the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. This detector serves as a ...prototype for the in-pocket particle detectors for future experiments with the Collector Ring (CR) at FAIR (Facility for Antiproton and Ion Research). The detector includes a stack of six silicon pad sensors, a double-sided silicon strip detector (DSSD), and a CsI(Tl) scintillation detector. It was used successfully in a recent experiment for the detection of the β+-decay of highly charged 142Pm60+ ions. Based on the ΔE/E technique for particle identification and an energy resolution of 0.9% for ΔE and 0.5% for E (Full Width at Half Maximum (FWHM)), the detector is well-suited to distinguish neighbouring isobars in the region of interest.
In bulk metal forming the tribological state is significantly dependent on the surface topography of tool and workpiece. To provide the process with an improved tribological behaviour in some cases ...the billet's surface is prepared by shot blasting. Micro texturing of the tool surface provides an additional opportunity to optimise the frictional conditions.
This paper deals with the investigation of micro texturing of the surface of TiN-coated tools with regard to their tribological behaviour in the field of cold forging. The micro textures are applied by excimer laser radiation. Tool life investigations in an industrial press shop yield that the tool surface can be improved significantly leading to higher tool life.
Neutron-induced reaction cross sections of unstable nuclei are essential for understanding the synthesis of heavy elements in stars. However, their measurement is very difficult due to the ...radioactivity of the targets involved. We propose to circumvent this problem by using for the first time the surrogate reaction method in inverse kinematics at heavy-ion storage rings. In this contribution, we describe the developments we have done to perform surrogate-reaction studies at the storage rings of GSI/FAIR. In particular, we present the first results of the proof of principle experiment, which we conducted recently at the Experimental Storage Ring (ESR).
Microtexturing of Cold-Forging Tools - Influence on Tool Life Popp, U; Engel, U
Proceedings of the Institution of Mechanical Engineers. Part B, Journal of engineering manufacture,
01/2006, Letnik:
220, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
Abstract
Friction and wear in metal-forming processes are dependent on several parameters, including sliding velocity, temperature, material combination, etc. Surface topography also plays an ...important role. It is evident that so-called lubricant pockets can improve the tribological state. Excimer laser material processing makes it possible to generate such pockets, even on complex-shaped, uncoated as well as coated-forming tools and with flexibility considering the arrangement and geometry of the textures. This paper deals with the investigation of the influence of direct laser texturing of coated tools on tribology in cold-forging processes. The arrangement, size, and geometry of the texture elements were chosen according to results of previous basic investigations. The tribological state is determined by means of industrial tool life tests. The results proved that tool life can be increased significantly, in some cases to more than 300 per cent.
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