Stochastic cooling experiments for CSRe at IMP Zhu, G.Y.; Wu, J.X.; Caspers, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2019, Letnik:
932
Journal Article
Recenzirano
A novel type of perforated travelling wave pick-up/kicker structure was developed for CSRe stochastic cooling which was originally proposed by F. Caspers at CERN. The simulated and measured results ...of shunt impedance of the slotted travelling wave pickup electrode are in reasonable agreement. In December 2015 stochastic cooling of heavy ions was successfully applied for the first time at the CSRe storage ring of IMP in Lanzhou, China. During four days of commissioning, transverse and longitudinal cooling could be observed. Both the time-of-flight and the notch filter methods were used for longitudinal cooling. The measured cooling rates are presented.
A fast and sensitive resonant Schottky pick-up for heavy ion storage rings Nolden, F.; Hülsmann, P.; Litvinov, Yu.A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2011, Letnik:
659, Številka:
1
Journal Article
Recenzirano
A resonant pick-up for the detection of heavy ion Schottky noise was built into the ESR storage ring at GSI. A similar device will be installed at the cooler storage ring CSRe at IMP. Its purpose is ...a significant enhancement of the signal to noise ratio of Schottky spectra. A particular application of the new system is the measurement of circulating single ions. The resonator is based on a pillbox design. It is operated at air pressure, and is electromagnetically coupled to the vacuum tube of the storage ring via a cylinder-shaped ceramic gap. The resonant frequency can be changed by inserting plunger pistons. The resonator can easily be decoupled from the storage ring, if high beam impedances become a problem. The article describes the construction, electromagnetic properties of the pick-up as well as first experiments with heavy ion beams.
Accurate spectroscopy of highly-charged high-Z ions in a storage ring is demonstrated to be feasible by the use of specially adapted crystal optics. The method has been applied for the measurement of ...the 1s Lamb shift in hydrogen-like gold (Au+78) in a storage ring through spectroscopy of the Lyman x-rays. This measurement represents the first result obtained for a high-Z element using high-resolution wavelength-dispersive spectroscopy in the hard x-ray regime, paving the way for sensitivity to higher-order QED effects.
Electron cooling experiments at the ESR Steck, M.; Beller, P.; Beckert, K. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2004, Letnik:
532, Številka:
1-2
Journal Article
Recenzirano
The properties of electron cooled beams of highly charged ions have been studied at the ESR. New experiments using a beam scraper to determine the transverse beam size provide the beam parameters in ...the intrabeam scattering dominated intensity regime, but also at very low intensity when the ion beam enters into an ultra-cold state. Extremely low values of longitudinal and transverse beam temperature on the order of meV were achieved for less than 1000 stored ions. An experiment with bunched ultra-cold beam showed a limit of the line density which agrees with the one observed for coasting beams. Cooling of decelerated ions at a minimum energy of 3MeV/u has been demonstrated recently.
Performance of the resonant Schottky pickup at CSRe Wu, J.X.; Zang, Y.D.; Nolden, F. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
12/2013, Letnik:
317
Journal Article
Recenzirano
Odprti dostop
•The single particle sensitivity of the new resonant pickup installed on CSRe was successfully confirmed.•This device will be used for nuclear mass and lifetime measurement, as well as other ...uses.•For the R/Q measurement, the perturbation measurement and the beam measurement have good agreements.
For a bunched beam, the signals on pickups are coherent, providing a signal power proportional to the square of the number of particles. For a coasting beam the individual particle signals have a random phase; therefore, the overall signal is proportional to the particle number N. As a consequence, Schottky signals are often relatively weak and have to compete with many noise sources. For a small number of particles, the S/N is always a problem. To achieve a high signal-to-noise ratio and better temporal resolution, which could yield important physical information about fast processes, a resonant pickup was developed at GSI (Nolden et al., 2011 1), and a similar device is now installed in the CSRe 2 at IMP. This device will be used for nuclear mass and lifetime measurement, as well as other uses. The final goal of the pickup is to detect single particles. In Dec 2012, we performed an experiment with a 112Sn50+ beam with an energy of 253MeV/u, and the single particle sensitivity of the pickup was successfully confirmed. This paper presents hardware measurements of the pickup as well as beam measurements.
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.
An optical technique to study the longitudinal distribution of ions in a bunched ion beam circulating in a storage ring is presented. It is based on the arrival-time analysis of photons emitted after ...collisional excitation of residual gas molecules. The beam-induced fluorescence was investigated in the ultraviolet regime with a channeltron and in the visible region using a photomultiplier tube. Both were applied to investigate the longitudinal shape of bunched and electron-cooled 209Bi80+ ion beams at about 400MeV/u in the experimental storage ring (ESR) at GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. Bunch lengths were determined with an uncertainty of about 0.5m using the UV-sensitive channeltron and with slightly lower accuracy from the photomultiplier data due to the slower transitions in the red region of the spectrum. The Gaussian shape of the longitudinal distribution of ions inside the bunch was confirmed. With the information of the transverse beam size that can be measured simultaneously by a newly installed ionization profile monitor (IPM) at the ESR, an accurate determination of the ion density in the bunched beam will be allowed.
► Optical methods to measure the bunch shape of ion beam at storage ring. ► High resolution of bunch length was obtained from the UV-sensitive channeltron. ► The Gaussian shape of longitudinal distribution of the ions in the bunch was confirmed.
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