A5101904814- Atomic and Molecular Physics
- Mass Spectrometry Techniques and Applications
- Advanced Chemical Physics Studies
- Photocathodes and Microchannel Plates
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Radiation Detection and Scintillator Technologies
- Advanced Optical Sensing Technologies
- Particle accelerators and beam dynamics
- CCD and CMOS Imaging Sensors
- Quantum, superfluid, helium dynamics
- Atmospheric Ozone and Climate
- Radiation Therapy and Dosimetry
- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Laser-Matter Interactions and Applications
- Astrophysics and Star Formation Studies
- Ion-surface interactions and analysis
- Scientific Measurement and Uncertainty Evaluation
- Plasma Diagnostics and Applications
- Particle Detector Development and Performance
- Nuclear physics research studies
- Laser-induced spectroscopy and plasma
- GaN-based semiconductor devices and materials
- Optical properties and cooling technologies in crystalline materials
Max Planck Institute for Nuclear Physics
2005-2019
Weizmann Institute of Science
2010-2016
Columbia University
2016
Max Planck Society
2002-2012
Justus-Liebig-Universität Gießen
2007
An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, put into operation. With a circumference 35 m, the ion-beam vacuum chambers all beam optics are in cryostat cooled by closed-cycle liquid helium system. At temperatures as low (5.5 ± 1) K inside time constants several minutes almost an hour were observed atomic molecular, anion cation at 60 keV. The intensity, energy-dependent...
The energy-resolved rate coefficient for the dissociative recombination (DR) of $\mathrm{H}_{3}{}^{+}$ with slow electrons has been measured by storage-ring method using an ion beam produced from a radiofrequency multipole trap, employing buffer-gas cooling at 13 K. electron energy spread merged-beams measurement is reduced to $500\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$ cryogenic GaAs photocathode. This and previous cold-$\mathrm{H}_{3}{}^{+}$ jointly confirm capability storage rings,...
Term energies for dielectronic-recombination Rydberg resonances below 0.07 eV are determined Sc18+ with absolute accuracies 0.0002 by electron collision spectroscopy in an ion storage ring, using the twin-electron-beam technique and a cryogenic photocathode. The lithiumlike 2s_{1/2}-2p_{3/2} transition energy Z=21 is to 4.6 ppm, less than 1% of few-body effects on radiative corrections. Features from hyperfine structure 2s state could be resolved spectrum.
The hyperfine induced 2s 2p 3P0 > 2s2 1S0 transition rate AHFI in berylliumlike 47Ti18+ was measured. Resonant electron-ion recombination a heavy-ion storage ring employed to monitor the time dependent population of state. experimental value AHFI=0.56(3)/s is almost 60% larger than theoretically predicted.
We report on the realization and operation of a fast ion beam trap linear electrostatic type employing liquid helium cooling to reach extremely low blackbody radiation temperature residual gas density and, hence, long storage times more than 5 min which are unprecedented for keV beams. Inside pipe that can be cooled temperatures <15 K, with 1.8 K reached in some locations, an pulse stored at kinetic energies 2-20 between two mirrors. Along overview cryogenic design, we present measurement...
Enhanced abundance of primordial HeH + Though only recently detected in space, the helium hydride ion (HeH ) is thought to be first molecule ever have formed early Universe. Novotný et al. report state-specific rate coefficients for dissociative reaction with electrons, obtained using a cryogenic storage ring combined merged electron beam (see Perspective by Bovino and Galli). They detect substantial rotational dependence decrease rates lowest states , far below values listed astrochemistry...
High-resolution dissociative recombination rate coefficients of rotationally cool and hot ${\mathrm{H}}_{3}^{+}$ in the vibrational ground state have been measured with a 22-pole trap setup Penning ion source, respectively, at storage-ring TSR. The experimental results are compared theoretical calculations to explore dependence coefficient on temperature study contributions different symmetries probe rich predicted resonance spectrum. kinetic energy release was investigated by fragment...
We describe a fast data-driven optical camera, Tpx3Cam, with nanosecond scale timing resolution and 80 Mpixel/sec throughput. After the addition of intensifier, camera is single photon sensitive quantum efficiency determined primarily by intensifier photocathode. The performance was characterized results on gain, afterpulsing reported here. intensified successfully used for measurements in variety applications including applications. As an example such application, which requires...
Using event-by-event fragment momentum spectroscopy in a storage-ring merged-beams experiment, we find laboratory evidence that the dissociative recombination (DR) of HCNH+ with cold electrons energetic isomer HNC is produced high yield, similar to HCN. With newly implemented mass-sensitive imaging detector, analyze kinetic energy release triatomic fragments DCN/DNC from DR reaction isotopologue DCND+ (near 10 K) electrons. The results show internal these extremely high, far exceeding...
A novel cryogenic electrostatic storage ring is planned to be built at the Max-Planck Institute for Nuclear Physics in Heidelberg. The machine expected operate low temperatures (∼2K) and store beams with kinetic energies between 20 300 keV. An electron target based on cooled photocathode technology will serve as a major tool study of reactions molecular ions electrons. Moreover, atomic can merged crossed stored ion allowing atom molecular-ion collision studies very up high relative energies....
We report on our recent studies of dissociative recombination (DR) employing two different fragment imaging detection techniques at the TSR storage ring in Heidelberg, Germany. Principles an upgraded 3D optical system and new energy-sensitive multistrip detector (EMU) are explained together with possible applications reaction dynamics studies. With EMU we succeeded to observe branching ratios after DR deuterated hydronium ions D(3)O(+) energies 0-0.5 4-21 eV. The almost constant low while...
We have measured electron–ion recombination for C-like Mg6 + forming Mg5 +, and B-like Mg7 +. These studies were performed using a merged beam arrangement at the TSR heavy ion storage ring located in Heidelberg, Germany. Both primary ions metastable levels with significant lifetimes. Using simple cascade model we estimate population fractions these levels. For results, find that majority of stored are level, while fraction is insignificant. present beams rate coefficient DR via N = 2 → N'...
Multi Micro-Channel-Plate Photomultiplier tubes (MCP-PMT) with High Collection Efficiency (Hi-CE) MCPs are developed and characterised. With these Hi-CE more than 90% of photoelectrons emitted from the photocathode can be detected; this is in contrast to conventional where about 50% lost at MCP stage. The drawback a small degradation transfer time spread (TTS). However for applications no sub-ns resolution required implementation extremely beneficial, as it improves detection efficiency...
Measurements on the energetic structure of dissociative recombination rate coefficient in millielectronvolt range are described for ions produced lowest rotational levels by collisional cooling and stored as a fast beam magnetic storage ring TSR (Test Storage Ring). The observed resonant is consistent with that found previously at facility CRYRING Stockholm, Sweden; theoretical predictions yield good agreement overall size coefficient, but do not reproduce detailed structure. First studies...
The electron-ion recombination rate coefficient for $\mathrm{Si}\phantom{\rule{0.3em}{0ex}}\mathrm{IV}$ forming $\mathrm{Si}\phantom{\rule{0.3em}{0ex}}\mathrm{III}$ was measured at the heavy-ion storage-ring TSR. experimental collision energy range of $0$--$186\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ encompassed $2{p}^{6}nl{n}^{\ensuremath{'}}{l}^{\ensuremath{'}}$ dielectronic (DR) resonances associated with $3s\ensuremath{\rightarrow}nl$ core excitations,...
We have measured electron-ion recombination for Fe$^{9+}$ forming Fe$^{8+}$ and Fe$^{10+}$ using merged beams at the TSR heavy-ion storage-ring in Heidelberg. The rate coefficients (MBRRC) relative energies from 0 to 75 eV are presented, covering all dielectronic (DR) resonances associated with 3s->3p 3p->3d core transitions spectroscopic species Fe X XI, respectively. compare our experimental results multi-configuration Breit-Pauli (MCBP) calculations find significant differences. From...
We have investigated the radiative cooling of initially hot Al−4 and Al−5 cluster anions during storage in a cryogenic ion beam trap at an ambient temperature <15 K. By applying statistical rate model to ions' measured delayed detachment following excitation with laser, we obtained their vibrational as function time. The curves for suggest that slows down considerably once reaches approximately room temperature. This suggests participation transitions from recently found low-lying electronic...
Based on conventional S-20 processes, a new series of high quantum efficiency (QE) photocathodes has been developed that can be specifically tuned for use in the ultraviolet, blue or green regions spectrum. The QE values exceed 30% at maximum response, and dark count rate is found to as low 30 Hz/cm$^2$ room temperature. This combination properties along with fast temporal response makes these ideal application photon counting detectors, which illustrated an MCP photomultiplier tube single...
Low-energy dielectronic recombination resonances of beryllium-like Ge28+ have been studied by electron collision spectroscopy in the heavy-ion storage ring TSR using a twin-electron beam technique combined with an ultracold photoelectron source. Rich resonance structure below 1.7 eV is observed which mainly arises from resonant capture free to 91 Rydberg states accompanied excitation inner valence electrons 2s2(1S0) ground state 2s2p(1P1). The positions 0.3 are measured accuracy better than...
Dielectronic recombination of highly charged atomic ions and dissociative molecular have been investigated using fast ion beams merged with cold intense electron (down to <1meV beam temperature) from a GaAs photocathode. For beryllium-like germanium (Ge28+) isolated fine structure Rydberg resonances (n = 9 14) were observed at <0.2eV revealing configuration interaction triply excited appearing as candidates for deriving radiative shifts the 2s2-2s2p(3P0) excitation energy. hydrogen fluoride...
A spin-dependent emission of optically oriented electrons from $p\text{-GaAs}(\text{Cs},\text{O})$ into vacuum was experimentally observed in a magnetic field normal to the surface. This phenomenon is explained within model which takes account jump electron $g$ factor at semiconductor-vacuum interface. Due this jump, effective affinity on semiconductor surface depends mutual direction spins and field, resulting photoemission. It demonstrated that effect can be used for determination spin...
A cryogenic electrostatic ion storage ring CSR is under development at the Max‐Planck Institute for Nuclear Physics in Heidelberg, Germany. Cooling of ultrahigh vacuum chamber envisaged to lead extremely low pressures as demonstrated by traps. The will apply electron cooling with beams a few eV up 200 eV. Through long times 1000 s well through wall temperature, internal infrared‐active molecular ions their rotational ground state be possible and collisions merged collinear electrons neutral...