| 1. |
- Abele, H., et al.
(författare)
-
Particle physics at the European Spallation Source
- 2023
-
Ingår i: Physics reports. - : Elsevier. - 0370-1573 .- 1873-6270. ; 1023, s. 1-84
-
Forskningsöversikt (refereegranskat)abstract
- Presently under construction in Lund, Sweden, the European Spallation Source (ESS) will be the world’s brightest neutron source. As such, it has the potential for a particle physics program with a unique reach and which is complementary to that available at other facilities. This paper describes proposed particle physics activities for the ESS. These encompass the exploitation of both the neutrons and neutrinos produced at the ESS for high precision (sensitivity) measurements (searches).
|
|
| 2. |
|
|
| 3. |
- Schmidt, HT, et al.
(författare)
-
Recoil-ion momentum distributions for transfer ionization in fast proton-He collisions
- 2005
-
Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American physical society. - 1050-2947 .- 1094-1622. ; 72:1
-
Tidskriftsartikel (refereegranskat)abstract
- We present high-luminosity experimental investigations of the transfer ionization (TI:p+He -> H-0+He2++e(-)) process in collisions between fast protons and neutral helium atoms in the earlier inaccessibly high-energy range 1.4-5.8 MeV. The protons were stored in the heavy-ion storage and cooler ring CRYRING, where they intersected a narrow supersonic helium gas jet. We discuss the longitudinal recoil-ion momentum distribution, as measured by means of cold-target recoil-ion momentum spectroscopy and find that this distribution splits into two completely separated peaks at the high end of our energy range. These separate contributions are discussed in terms of the earlier proposed Thomas TI (TTI) and kinematic TI mechansims. The cross section of the TTI process is found to follow a sigma proportional to v(-b) dependence with b=10.78 +/- 0.27 in accordance with the expected v(-11) asymptotic behavior. Further, we discuss the probability for shake-off accompanying electron transfer and the relation of this TI mechanism to photodouble ionization. Finally the influence of the initial-state electron velocity distribution on the TTI process is discussed.
|
|
| 4. |
|
|
| 5. |
- Böhm, S, et al.
(författare)
-
Enhancement of dielectronic recombination by external electromagnetic fields
- 2003
-
Ingår i: Hyperfine Interactions. - 0304-3843. ; 146-147:1-4, s. 23-27
-
Tidskriftsartikel (refereegranskat)abstract
- The enhancement of the dielectronic recombination rate of lithiumlike Ne7+ and O5+ ions by external electromagnetic fields has been measured at the storage ring CRYRING. The energy range covered all 1s(2)2pnl dielectronic recombination resonances attached to the 2s --> 2p core excitation. Electric fields up to 1436 V/cm were applied in the Ne7+ experiment and the saturation of the enhancement with increasing electric field could clearly be seen. In the O5+ experiment the enhancement was studied as a function of the Rydberg quantum number n.
|
|
| 6. |
- Böhm, S, et al.
(författare)
-
Influence of electromagnetic fields on the dielectronic recombination of Ne7+ and O5+ ions
- 2001
-
Ingår i: Physica Scripta. Topical Issues. - 0281-1847. ; T92, s. 395-397
-
Tidskriftsartikel (refereegranskat)abstract
- Within a series of measurements of the dielectronic recombination (DR) of lithium-like ions we have determined the enhancement of the recombination rate in the presence of crossed electric and magnetic fields for Ne7+ and O5+ ions. In both cases the electron energy range covers a DR resonances attached to 2s --> 2p(1/2) and 2s --> 2p(3/2) Delta_n = 0 core excitations. For increasing field the enhancement factor first increases linearly with the electric field and then saturates. In order to investigate the field effect on high-n Rydberg states the ion energy in the O5+ experiment was changed from 9.4 MeV/u to 5 MeV/u and 3.26 MeV/u. With the variation of the ion energy the field ionization of Rydberg states in the analyzing magnet is influenced. This enabled us to study the field enhancement for a narrow bandwidth of n-states.
|
|
| 7. |
- Böhm, S, et al.
(författare)
-
Influence of electromagnetic fields on the dielectronic recombination of Ne7+ ions
- 2001
-
Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947. ; 64:3, s. 032707/1-032707/7
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of crossed electric and magnetic fields on dielectronic recombination of Ne7+ ions has been measured at the Stockholm heavy-ion storage ring CRYRING. The electron energy range covered all dielectronic recombination resonances attached to 2s-2p1/2 and 2s-2p3/2 core excitations. Two sets of measurements at magnetic fields of 180 mT and 30 mT have been performed. For the measurement at 180 mT we applied 25 different electric fields between 0 and 1400 V/cm. The resonance strength for dielectronic recombination via high Rydberg states initially increases linearly with electric field and later levels out. At a magnetic field of 30 mT we applied 15 different electric fields ranging from 0 to 140 V/cm. Compared to the measurement at 180 mT the initial slope of the rate enhancement was larger by almost a factor of 2. The fraction of resonant strength not measured due to field ionization is estimated by a model calculation of dielectronic recombination cross sections.
|
|
| 8. |
- Gatchell, Michael, et al.
(författare)
-
Commissioning of the DESIREE storage rings - a new facility for cold ion-ion collisions
- 2014
-
Ingår i: XXVIII International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2013). - : Institute of Physics (IOP). ; 488:1
-
Konferensbidrag (refereegranskat)abstract
- We report on the ongoing commissioning of the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. Beams of atomic carbon anions (C-) and smaller carbon anion molecules (C-2(-), C-3(-), C-4(-) etc.) have been produced in a sputter ion source, accelerated to 10 keV or 20 keV, and stored successfully in the two electrostatic rings. The rings are enclosed in a common vacuum chamber cooled to below 13 Kelvin. The DESIREE facility allows for studies of internally relaxed single isolated atomic, molecular and cluster ions and for collision experiments between cat-and anions down to very low center-of-mass collision energies (meV scale). The total thermal load of the vacuum chamber at this temperature is measured to be 32 W. The decay rates of stored ion beams have two components: a non-exponential component caused by the space charge of the beam itself which dominates at early times and an exponential term from the neutralization of the beam in collisions with residual gas at later times. The residual gas limited storage lifetime of carbon anions in the symmetric ring is over seven minutes while the 1/e lifetime in the asymmetric ring is measured to be about 30 seconds. Although we aim to improve the storage in the second ring, the number of stored ions are now sufficient for many merged beams experiments with positive and negative ions requiring milliseconds to seconds ion storage.
|
|
| 9. |
- Wildner, E., et al.
(författare)
-
The Opportunity Offered by the ESSnuSB Project to Exploit the Larger Leptonic CP Violation Signal at the Second Oscillation Maximum and the Requirements of This Project on the ESS Accelerator Complex
- 2016
-
Ingår i: Advances in High Energy Physics. - : Hindawi Publishing Corporation. - 1687-7357 .- 1687-7365.
-
Tidskriftsartikel (refereegranskat)abstract
- The European Spallation Source (ESS), currently under construction in Lund, Sweden, is a research center that will provide, by 2023, the world's most powerful neutron source. The average power of the proton linac will be 5 MW. Pulsing this linac at higher frequency will make it possible to raise the average total beam power to 10 MW to produce, in parallel with the spallation neutron production, a very intense neutrino Super Beam of about 0.4 GeV mean neutrino energy. This will allow searching for leptonic CP violation at the second oscillation maximum where the sensitivity is about 3 times higher than at the first. The ESS neutrino Super Beam, ESSnuSB operated with a 2.0 GeV linac proton beam, together with a large undergroundWater Cherenkov detector located at 540 km from Lund, will make it possible to discover leptonic CP violation at 5 sigma. significance level in 56% (65% for an upgrade to 2.5 GeV beam energy) of the leptonic CP-violating phase range after 10 years of data taking, assuming a 5% systematic error in the neutrino flux and 10% in the neutrino cross section. The paper presents the outstanding physics reach possible for CP violation with ESSnuSB obtainable under these assumptions for the systematic errors. It also describes the upgrade of the ESS accelerator complex required for ESSnuSB.
|
|
| 10. |
- Aguilar, J., et al.
(författare)
-
Search for Leptonic CP Violation with the ESSnuSBplus Project
- 2024
-
Ingår i: Letters in High Energy Physics. - : Andromeda Publishing And Academic Services LTD. - 2632-2714.
-
Tidskriftsartikel (refereegranskat)abstract
- ESSνSB is a design study for a next-generation long-baseline neutrino experiment that aims at the precise measurement of the CP-violating phase, δCP, in the leptonic sector at the second oscillation maximum. The conceptual design report published from the first phase of the project showed that after 10 years of data taking, more than 70% of the possible δCP range will be covered with 5σ C.L. to reject the no-CP-violation hypothesis. The expected value of δCP precision is smaller than 8◦ for all δCP values. The next phase of the project, the ESSνSB+, aims at using the intense muon flux produced together with neutrinos to measure the neutrino-nucleus cross-section, the dominant term of the systematic uncertainty, in the energy range of 0.2–0.6 GeV, using a Low Energy neutrinos from STORed Muons (LEnuSTORM) and a Low Energy Monitored Neutrino Beam (LEMNB) facilities.
|
|
