| Paper | Title | Page |
|---|---|---|
| MOPAB067 | Response of Scintillating Screens to High Charge Density Electron Beam | 268 |
|
||
| Inorganic scintillating screens are very useful tool to measure transverse profile of charged particle beams. The cerium-doped yttrium:aluminum:garnet (YAG:Ce) crystal scintillator is used in many accelerating facilities. The scintillating screen shows good resolution comparable to that of OTR screen. However, response to high charge density electron beam, more than 10 nC per square millimeter, has not been clarified. In KEK e+/e− injector linac, the charge areal density (σ) will exceed 25 nC per square mm. Thus, beam tests has been performed on YAG:Ce, LYSO, and BGO crystals for 1.5 GeV, 1 nC/bunch electron beam at the linac. Saturation of the luminescence which causes degradation of the resolution has been observed above 1 nC per square mm in those crystals. We will report the response of the scintillating screens to high charge density electron beam and discuss the degradation of the resolution due to the saturation of the light yield. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB067 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPAB004 | Progress of 7-GeV SuperKEKB Injector Linac Upgrade and Commissioning | 1300 |
|
||
| KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It is being upgraded for the SuperKEKB project, which aims at a 40-fold increase in luminosity over the previous project KEKB, in order to increase our understanding of new physics beyond the standard model of elementary particle physics. SuperKEKB asymmetric electron and positron collider with its extremely high luminosity requires a high current, low emittance and low energy spread injection beam from the injector. Electron beams will be generated by a new type of RF gun, that will provide a much higher beam current to correspond to a large stored beam current and a short lifetime in the ring. The positron source is another major challenge that enhances the positron bunch intensity from 1 to 4 nC by increasing the positron capture efficiency, and the positron beam emittance is reduced from 2000 micron to 20 micron in the vertical plane by introducing a damping ring, followed by the bunch compressor and energy compressor. The recent status of the upgrade and beam commissioning is reported. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB004 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPAB005 | Investigation of Beam Variation and Emittance Growth Simulation With Both Misalignments and the Beam Jitter for SuperKEKB Injector Linac | 1304 |
|
||
|
Funding: This work was supported by JSPS KAKENHI Grant Number 16K17545. The SuperKEKB is e+/e− circular collider for high luminosity, 8Â¥times1035 as a target value. For the high luminosity, the injector linac is required to transport low emittance high-charged electron beam and positron beam to the ring. A charged beam with an offset from a center of cavity is affected by the wakefield depending on both the offset size in the cavity and longitudinal particle position in the beam. The wakefield causes emittance growth. This growth can be suppressed by appropriate orbit control so as to cancel the wakefield effect of the cavities in total. On the other hands, the beam variation in 6-dimensional phase space also induces the emittance growth. Emittance growth by both misalignments and 6-dimensional beam jitter was evaluated by particle tracking simulation. Investigation of beam jitter and drift was also performed by correlation analysis between beam position and measured parameter, charge or temperature. |
||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB005 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPAB014 | Preliminary Design of FCC-ee Pre-Injector Complex | 1337 |
| SUSPSIK006 | use link to see paper's listing under its alternate paper code | |
|
||
| The design of a 100 km circular e+e− collider with extremely high luminosity is an important component of the global Future Circular Collider (FCC) study hosted by CERN. FCC-ee is being designed to serve as Z, W, H and top factory, covering beam energies from 45.6 to 175 GeV. For the injectors, the Z-operation is the most challenging mode, due to the high total charge and low equilibrium emittance in the collider at this energy. Thus, fulfilling the Z-mode will also meet the demands for all other modes of FCC-ee. This goal can be achieved by using a 6 GeV NC linac with an S-band RF frequency of 2.856 GHz and a repetition rate of 100 Hz. This linac will accelerate two bunches per RF pulse, each with a charge of 6.5 nC. Positrons will be generated by sending 4.46 GeV e- onto a hybrid target so that the e+ created can still be accelerated to 1.54 GeV in the remaining part of the same linac. The emittance of the e+ beam will then shrink to the nm level in a 1.54 GeV damping ring. After damping, the e+ will be reinjected into the linac and accelerated to 6 GeV. The e- and e+ will then be accelerated alternately to 45.6 GeV in the booster, before they are injected into the collider. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB014 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| WEPAB044 | Construction and Commissioning of Direct Beam Transport Line for PF-AR | 2678 |
|
||
| PF-AR was constructed as an accumulator ring for TRISTAN, and in the KEKB era it has been revitalized as a 6.5 GeV synchrotron radiation source. The injection energy was 3 GeV and the beam was accelerated to 6.5 GeV prior to the user run. The original beam transport line (BT) from the LINAC to the PF-AR shared its upstream part with the the BT line of KEKB High Energy Ring (HER). The injection-mode change from PF-AR to HER or vice versa needs about 10 minutes for the magnet cycling procedure of the shared part. In SuperKEKB, the upgrade of KEKB, the lifetime of HER is about 10 minutes. The mode-switch operation of the BT is, therefore, not allowed for maintaining the highest luminosity of the SuperKEKB. In order to avoid this problem, a new 6.5 GeV BT line dedicated to PF-AR has been constructed. This also enables the top-up injection for the user run. The commissioning of the new BT line has been completed in this March, and now the first user run has been operated successfully. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB044 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| WEPIK002 | Experimental Activities on High Intensity Positron Sources Using Channeling | 2910 |
|
||
| The positron source under investigation is using channeling radiation of multi-GeV electrons in a tungsten crystal. The radiated photons are impinging on the amorphous targets creating e+e− pairs. A dipole magnet between the crystal-radiator and the amorphous-converter allows the charged particles to be swept off and only emitted photons to generate e+e− pairs in the converter. Granular targets of different thicknesses, made of small tungsten spheres, have been recently investigated as a target-converter. This paper is describing the experimental studies conducted at the KEKB linac with such device. After the description of the experimental set-up and beam parameters, the measurement methods and preliminary results are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK002 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |