| Paper | Title | Page |
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| MOPRO033 | Design and Feasibility Study of a Transverse Halo Collimation System for ATF2 | 145 |
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Funding: Work supported by FPA2010-21456-C02-01 and by i-link 0704 This paper presents the design of a halo collimation system for the ATF2 beamline. The main objective is the reduction of background noise that limits the performance of key diagnostic devices around the final focal point (IP), especially the Shintake Monitor (IPBSM) used for measuring the nanometer level vertical beam sizes and the future Diamond Sensor (DS) for measuring the beam halo. Beam tracking simulations have been performed to optimize the position and characteristics of the halo collimation devices. Furthermore the collimator wakefield-induced effect is being studied. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO033 | |
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| TUPME005 | CLIC FFS Lattice Proposals Combining Local and Non-local Chromaticity Corrections | 1343 |
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| The requirements on the Final Focusing System (FFS) for a new linear collider has lead to lattice designs where chromaticity is corrected either locally or non-locally. Here, alternative proposals of lattice design are presented for the current CLIC 500GeV beam parameters, combining the local chromaticity correction on the vertical plane and non-local correction on the horizontal. The tight tolerance on phase advances and beta functions imposed to obtain -I transformation required to cancel the chromatic terms is relaxed by enlarging the system length and using a more general transformation definition, aiming to obtain better results in tuning simulations. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME005 | |
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| THPME090 | Fast Luminosity Monitoring using Diamond Sensors for the Super Flavor Factory SuperKEKB | 3442 |
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| Super luminous flavor factories, as SuperKEKB in Japan, aim to achieve very high luminosity thanks to a newly employed concept, the nano-beam scheme, where ultra-low emittance beams collide at very large crossing angle . Luminosity optimisation and dynamic imperfections require fast luminosity measurements. The aimed precision, 10-3 in 10 ms, can be achieved thanks to the very large cross-section of the radiative Bhabha process at zero-photon scattering angle. As a result of huge particle fluxes, diamond sensors are chosen to be placed just outside the beam-pipe, downstream of the interaction point, at locations with event rates consistent with the aimed precision and small enough contamination by backgrounds from single-beam particle losses . We will present the results concerning the investigation of the optimal positioning of our diamond sensors, taking into account the rate of Bhabha particles, their interactions with the beam pipe material. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME090 | |
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| THPME091 | Beam Halo Measurements using Wire Scanners at ATF2 | 3445 |
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Funding: Chinese Scholarship Council, FPA2010-21456-C02-01 and i-link 0704 Beam halo hitting on the beam pipe after the Interaction Point (IP) can generate a large amount of background for the measurements of the nano meter beam size using the laser interferometer beam size monitor (Shintake monitor) at ATF2. In order to investigate the beam halo transverse distribution, a diamond detector will be installed downstream of the IP. A feasibility study of a transverse halo collimation system to reduce the background for these measurements is also in progress. Prior to the diamond detector installation, a first attempt of beam halo measurements have been performed in 2013 using the currently installed wire scanners. Modeling of the beam halo distribution in the extraction (EXT) line was done and compared with the old modeling for ATF. Beam halo measurements were also done using the post-IP wire scanner to investigate the beam halo distribution at post-IP. Work supported by Chinese Scholarship Council, FPA2010-21456-C02-01 and i-link 0704 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME091 | |
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| THPME092 | Status of Diamond Detector Development for Beam Halo Investigation at ATF2 | 3449 |
| SUSPSNE070 | use link to see paper's listing under its alternate paper code | |
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Funding: Chinese Scholarship Council We are developing a diamond detector for beam halo and Compton spectrum diagnostics after the interaction point (IP) of ATF2, a low energy (1.3 GeV) prototype of the final focus system for ILC and CLIC linear collider projects. Tests of a 500 μm thick sCVD diamond detector with a dimension of 4.5 mm×4.5 mm have been carried out with radioactive sources and with electron beam from PHIL low energy (<10 MeV) photo-injector at LAL. The tests at PHIL were done with different beam intensities in air, just after the exit window at the end of the beam line, to test the response of the diamond detector and the readout electronics. We have successfully detected signals from single electrons, using a 40 dB amplifier, and from an electron beam of 108 electrons, using a 24 dB attenuator. A diamond sensor with 4 strips has been designed and fabricated for installation in the vacuum chambers of ATF2 and PHIL, with the aim to scan both the beam halo (with 2 strips of 1.5 mm×4 mm) and the beam core (with 2 strips of 0.1 mm×4 mm) transverse distributions. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME092 | |
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| THPME094 | Measurement of Low-charged Electron Beam with a scintillator Screen | 3456 |
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| Measuring electron beam charge lower than 1pC is very challenging since the traditional diagnostics, like Faraday Cup and ICT, are limited in resolution to a few pC. A way to simply measure lower charge would be to use the linear relation, existing before saturation regime, between the incident charge and the total light intensity emitted by a YAG screen. Measurement has been performed on PHIL accelerator at LAL, with charge lower than 50pC, with a YAG screen located just in front of a Faraday Cup. It shows a very good linear response of the YAG screen up to the Faraday Cup resolution limit (2pC) and therefore allows calibrating the YAG screen for lower charge measurement with an estimated precision of 4%. A noise analysis allows estimating the YAG screen resolution limit around 40fC. Results of low charge measurement on PHIL will be shown and compared to those coming from a diamond detector installed on PHIL, in order to validate the measurement principle and to determine its precision and resolution limit. Such simple measurement may thereafter be used as single-shot charge diagnostic for electron beam generated and accelerated by laser-plasma interaction. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME094 | |
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| THPME147 | The High Position Resolution Cavity BPM Developments and Measurement for ILC Final Focus System | 3599 |
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| An ultra high position resolution cavity BPM was developed for the final focus system of ATF2, which is a accelerator test facility for ILC final focus system. The main purpose of ATF2 are achievement of 37 nm beam size and nano-meter beam orbit stability at IP(Interaction Point). For these purposes, a few nano meter beam position resolution was required for this cavity BPM, which is called the IP-BPM. The IP-BPM was fabricated 2 blocks of IP-BPM, the first block consists of two cavities in one block and second block consists of single cavity. IP-BPM can measure beam position in vertical and horizontal independently by using rectangular shape single cavity. Three IP-BPMs were installed at ATF IP region inside IP-chamber, and its position resolution was measured. We will present the detailed results on the beam tests. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME147 | |
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