Keyword: timing
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MOPML032 Prospects for a Muon Spin Resonace Facility in the Fermilab MuCool Test Area target, linac, experiment, resonance 474
  • J.A. Johnstone, C. Johnstone
    Fermilab, Batavia, Illinois, USA
  Funding: Work supported by Fermi Reserach Alliance, LLC under Contract no. DE-AC02-07CH11359 with the United States Department of Energy.
This paper investigates the feasibility of re-purposing the MuCool Test Area beamline and experimental hall to support a Muon Spin Resonance Facility which would make it the only such facility in the US. This report reviews the basic muon production concepts as studied and operationally implemented at TRIUMF, PSI, and RAL and their application in the context of the MTA facility. Two scenarios were determined feasible. One, an initial minimal-shielding and capital-cost investment stage with a single secondary muon beamline that utilizes an existing primary beam absorber and, another, an upgraded stage, that implements an optimized production target, a proximate high-intensity absorber, and optimized secondary muon lines. A unique approach is proposed which chops or strips a macropulse of H beam into a micropulse substructure - a muon creation timing scheme - which allows Muon Spin Resonance experiments in a linac environment. With this timing scheme, and attention to target design and secondary beam collection, the MTA can host enabling and competitive Muon Spin Resonance experiments.
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MOPML072 Timing Resolution for an Optical Fibre-Based Detector in a 74 MeV Proton Therapy Beam proton, detector, TRIUMF, photon 575
  • C.A. Penner
    UBC & TRIUMF, Vancouver, British Columbia, Canada
  • C. Duzenli
    UBC, Vancouver, B.C., Canada
  • C.M. Hoehr, C. Lindsay
    TRIUMF, Vancouver, Canada
  • S. O'Keeffe
    University of Limerick, Limerick, Ireland
  A Terbium activated Gadolinium Oxysulfide (Gd2O2S:Tb)-filled optical fibre sensor was developed and tested as a proton therapy beam dosimeter on a 74 MeV proton beam. Tests were carried out at the TRIUMF proton therapy centre, where a passively scattered beam is used for treatment. To create a clinically relevant spread-out Bragg peak, a modulator wheel with steps of varying thickness is employed. To determine the sensor's response in a 23 mm spread out Bragg peak, the sensor signal was sampled at depth intervals of 0.79 mm along the beam axis in a water phantom. The resulting data showed a periodic variation in the signal corresponding to the rotation of the modulator wheel and related to the depth in water of the detector. This timing resolution in the sensor response could find application in quality assurance for modulated proton beams.  
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TUPAL005 Study on the Fixed Point Injection during the Beam Commissioning for CSNS injection, MMI, neutron, proton 1017
  • M.Y. Huang, H.C. Liu, S. Wang, S.Y. Xu
    IHEP, Beijing, People's Republic of China
  In order to inject the H beam into the Rapid Cycling Synchrotron (RCS) of China Spallation Neutron Source (CSNS) accurately, different injection methods were used in different periods of beam commissioning for CSNS. In the early stage of beam commissioning, since the precise relative position of the injection beam and circular beam was unknown and the injection beam power was relatively small, the fixed point injection method was used. In this paper, the fixed point injection method is studied in detail and the beam commissioning results are given and discussed. In addition, a method to adjust the timing of the injection pulse power is presented and confirmed by the beam commissioning.  
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TUZGBD2 Transverse and Longitudinal Bunch-by-Bunch Feedback for Storage Rings feedback, kicker, FPGA, damping 1198
  • T. Nakamura
    JASRI/SPring-8, Hyogo-ken, Japan
  Digital bunch-by-bunch feedback systems for betatron and synchrotron oscillation are powerful tools for suppression of beam instabilities and are indispensable for stable operation of storage rings. This invited talk reviews the world activities on transvers and longitudinal bunch-by-bunch feedback for storage rings.  
slides icon Slides TUZGBD2 [15.904 MB]  
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TUPMF016 Application of SVD Analysis to Deflecting Cavitiy Space Harmonics cavity, simulation, data-analysis, experiment 1283
  • C. Yao, L. Emery, D. Hui, H. Shang, Y.P. Sun
    ANL, Argonne, Illinois, USA
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Singular value decomposition (SVD) analysis is a powerful tool for identifying different spatial and timing variation patterns in many fields of researches. Recently we applied complex SVD method to space harmonic analysis of a 13-cell defecting cavity that is built and installed in the APS linac injector for beam phase space characterization and emittance exchange experiments. Real and imaginary space harmonics components are extracted from CST simulated data. Fields inside the iris were expressed in analytic forms and produced good agreement. Work is underway to implement the results into elegant simulation model.
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TUPMF082 FLASHForward: DOOCS Control System for a Beam-Driven Plasma-Wakefield Acceleration Experiment controls, laser, detector, hardware 1460
  • S. Karstensen, S. Bohlen, J. Dale, M. Dinter, J.M. Müller, P. Niknejadi, J. Osterhoff, K. Poder, P. Pourmoussavi, V. Rybnikov, L. Schaper, B. Schmidt, J.-P. Schwinkendorf, B. Sheeran, G.E. Tauscher, S. Thiele, S. Wesch, P. Winkler
    DESY, Hamburg, Germany
  The FLASHForward project at DESY is an innovative beam-driven plasma-wakefield acceleration experiment integrated in the FLASH facility, aiming to accelerate electron beams to GeV energies over a few centimetres of ionised gas. These accelerated beams are tested for their capability to demonstrate exponential free-electron laser gain; achievable only through rigorous analysis of both the driver and witness beam's phase space. The thematic priority covered in here the control system part of FLASHForward. To be able to control, read out and save data from the diagnostics into DAQ, the DOOCS control system has been integrated into FLASH Forward. Laser beam control, over 70 cameras, ADCs, timing system and motorised stages are combined into the one DOOCS control system as well as vacuum and magnet controls. Micro TCA for Physics (MTCA.4) is the solid basic computing system, supported from high power workstations for camera read-out and normal Linux computers.  
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TUPMK008 Highly-stable, High-power Picosecond Laser Optically Synchronized to a UV Photocathode Laser for an ICS Hard X-ray Generation laser, cathode, electron, linac 1504
  • K.-H. Hong
    MIT, Cambridge, Massachusetts, USA
  • D. Gadonas, L.M. Hand, K. Neimontas, A. Senin, V. Sinkevicius
    Light Conversion, Vilnius, Lithuania
  • W.S. Graves, M.R. Holl, L.E. Malin, C. Zhang
    Arizona State University, Tempe, USA
  • S. Klingebiel, T. Metzger, K. Michel
    TRUMPF Scientific Lasers GmbH + Co. KG, Munchen-Unterfoehring, Germany
  Under the CXLS project at Arizona State University we are developing an inverse Compton scattering (ICS) hard X-ray source* towards a compact XFEL with electron nano-bunching. The ICS interaction is critically dependent on the quality of driver pulses such as: 1) available peak intensity, 2) energy/pointing stability, and 3) relative timing stability to UV pulses initially triggering electron beams. Here, we report on a highly stable, 1 kHz, 200 mJ, 1.1 ps, 1030 nm laser with good beam quality as an ICS driver, optically synchronized to a UV photocathode laser. The ICS driver is based on a Yb:YAG thin-disk regenerative amplifier (RGA), ensuring an excellent energy stability (shot-to-shot 0.52% rms; 0.14% rms over 24 hours). The pointing stability better than 4 urad is obtained. The M2 factor is as good as ~1.5 at the full energy, leading to the achievable laser intensity of >1017 W/cm2 with f/10 focusing. The photocathode laser, a frequency-quadrupled Yb:KGW RGA, share a common seed oscillator with the ICS driver for optical synchronization. The residual sub-ps timing drift is further reduced to 33 fs rms using an optical locking scheme based on a parametric amplifier.
* W.S. Graves et al., "Compact X-ray source based on burst mode inverse compton scattering at 100 kHz," Phys. Rev. ST Accel. Beams, Vol. 17, p. 120701 (Dec. 2014).
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WEYGBF4 Development of a Solid-State Pulse Generator Driving Kicker Magnets for a Novel Injection System of a Low Emittance Storage Ring kicker, injection, high-voltage, storage-ring 1804
  • T. Inagaki, H. Tanaka
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • H. Akikawa, K. Sato
    Nihon Koshuha Co. Ltd, Yokohama, Japan
  • K. Fukami, C. Kondo, S. Takano
    Japan Synchrotron Radiation Research Institute (JASRI), RIKEN SPring-8 Center, Hyogo, Japan
  Funding: Funded by MEXT Japan
A next generation electron storage ring represented by a diffraction-limited light source pursues an extremely low emittance leading to a small dynamic aperture and short beam lifetime. The top-up injection is hence indispensable to keep the stored beam current. The beam orbit fluctuation caused by the injection magnets should seriously obstruct utilization of an electron beam with sharp transverse profile. In order to solve these problems, a novel off-axis in-vacuum beam injection system was proposed. In the system, twin kicker magnets driven by a single solid-state pulsed power supply to launch a linear pi- bump orbit is the key to suppress the horizontal orbit fluctuation down to a level of several microns. Here, a big challenge is to achieve the magnetic field identity of the two kickers within an accuracy of 0.1%. This presentation overviews the proposed injection system and reports the development status focusing on the solid-state pulse generator.
slides icon Slides WEYGBF4 [3.067 MB]  
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WEPAF007 A Scheme for Asynchronous Operation of the APS-U Booster Synchrotron booster, injection, storage-ring, extraction 1823
  • U. Wienands, T.G. Berenc, T. Fors, F. Lenkszus, N. Sereno, G.J. Waldschmidt
    ANL, Argonne, Illinois, USA
  Funding: Work supported by US DOE
The APS-U 6-GeV MBA storage ring will have 42 pm beam emittance and relatively tight acceptance. This requires limiting the beam emittance out of the Booster synchrotron which is achieved by operating the Booster off-momentum, thus manipulating the damping partitions. However, the much higher charge for the APS-U strongly favors injecting on momentum into the Booster for maximum acceptance. An rf-frequency ramping scheme is proposed to allow injecting on momentum and then moving the beam off momentum. The ramp is adjusted from cycle to cycle to vary the total time taken by the beam from injection to extraction, thus aligning the Booster bunch with any chosen MBA storage ring bucket. The two rf systems will not be locked at any time of the cycle. The proposed scheme is compatible with the existing synchronization of the APS injector cycle to the 60-Hz line voltage which induces a variation in the start time of the acceleration cycle. The scheme removes the need to realign the Booster ring for total path length while optimizing its operation for high charge acceleration. A ferrite tuner is being considered for dynamic tuning of the rf cavities.
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WEPAF043 Commissioning and Long-Term Results of a Fully-Automated Pulse-Based Optical Timing Distribution System at Dalian Coherent Light Source laser, electron, operation, detector 1909
  • H.P.H. Cheng, A. Berlin, E. Cano, A. Dai, J. Derksen, D. Forouher, W. Nasimzada, M. Neuhaus, P. Schiepel, E. Seibel, K. Shafak
    Cycle GmbH, Hamburg, Germany
  • Z. Chen, H.L. Ding, Z.G. He, Y.H. Tian, G.R. Wu
    DICP, Dalian, People's Republic of China
  • F.X. Kärtner
    Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
  • B. Liu, X.Q. Liu
    SINAP, Shanghai, People's Republic of China
  New generation light sources such as X-ray free-electron lasers* and attoscience centers** require high demand for timing synchronization, on the order of few femtoseconds or below, to generate ultrashort X-ray pulses that enables attosecond temporal and subatomic spatial resolution. The challenge in achieving this scientific dream lies in part in a reliable, high-precision timing distribution system that can synchronize various optical and microwave sources across multi-km distances with good long-term stability. It was shown that the pulsed-optical timing distribution system can deliver sub-fs long-term timing precision between remotely synchronized lasers and microwave sources in laboratory environment.*** We present the latest results from the commissioning of China's first multi-link pulse-based optical timing distribution system (TDS) installed at Dalian Coherent Light Source. Long term operating results of the fully-automated polarization-maintaining TDS, as well as lessons learned and recommendations for future improvements, are presented, including performance of the timing-stabilized PM fiber links, microwave end-stations and ultrafast laser synchronization end-stations.
**G. Mourou and T. Tajima, Science, 331, pp. 41-42, 2011.
***M. Xin et al., Light Sci. Appl., 6, e16187, 2017.
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WEPAF055 Time-Synchronized Beam Diagnostics at SPEAR3 diagnostics, feedback, kicker, injection 1948
  • Q. Lin, Z.H. Sun
    Donghua University, Shanghai, People's Republic of China
  • P. Boussina, W.J. Corbett, D.J. Martin, J.A. Safranek, K. Tian
    SLAC, Menlo Park, California, USA
  • D. Teytelman
    Dimtel, San Jose, USA
  The SPEAR3 timing system supplies a 10Hz trigger pulse synchronous with charge injection into the main storage ring. In the past the 10Hz pulse train has been used to study injected charge transients as seen by visible-light synchrotron radiation diagnostics and turn-by-turn BPMs. More recently the 10Hz pulse has been used to synchronize the bunch-by-bunch feedback data acquisition system with other triggered diagnostic systems. The suite of measurement systems can be used to study injected beam dynamics, grow/damp instability transients and drive/damp physics.  
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WEPAK014 A New Pulse Magnet Control System in the KEK Electron Positron LINAC controls, power-supply, EPICS, software 2121
  • Y. Enomoto, K. Furukawa, T. Natsui, M. Satoh
    KEK, Ibaraki, Japan
  • H.S. Saotome
    Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
  In 2017, sixty-four pules magnets were installed in the KEK e+/e LINAC for simultaneous injection to four different rings. Since each ring requires different injection energy, magnetic field in the LINAC has to be changed shot by shot (every 20 ms) according to the destination of the beam. To realize such operation, a PXI express based new control system was installed. Each unit, which consists of an event receiver board, a DAC board, and a ADC board, can set and monitor output current up to 8 pulsed power supply in 16 bit resolution. The timing and control system are integrated in that of the LINAC by using Micro-Research Finland's PXI event receiver board. In terms of software, Windows 8.1 and LabVIEW 2016 were mainly adopted to control the hardware. EPICS channel access (CA) protocol was used to communicate with operator's interface panels. In addition to real-time monitoring by EPICS CA and logging by CSS archiver every 10 s, data are logged every shot (every 20 ms) in the text file together with timestamp, shot ID and destination. At present, thirteen units are stably in operation to control 64 magnets. Further installation of the system is planned in 2018.  
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WEPAK018 LLRF Control Unit for SuperKEKB Injector Linac controls, LLRF, linac, klystron 2134
  • T. Miura, M. Akemoto, D.A. Arakawa, H. Katagiri, T. Matsumoto, F. Qiu, Y. Yano
    KEK, Ibaraki, Japan
  • N. Liu
    Sokendai, Ibaraki, Japan
  The low-level RF (LLRF) control unit based on the digital system has been developed for a stable and high precision pulse modulation for the SuperKEKB. The RF pulse is changed at a 50-Hz repetition rate for the top-up injection to four different rings by the event system. The LLRF control unit has not only the pulse modulator, but also other functions: VSWR meter, RF monitor, event receiver (EVR), and pulse-shortening detection.  
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WEPAL010 Review of the ELI-NP-GBS Low Level RF and Synchronization Systems LLRF, laser, linac, electron 2162
  • L. Piersanti, D. Alesini, M. Bellaveglia, F. Cardelli, M. Diomede, A. Gallo, V. Martinelli
    INFN/LNF, Frascati (Roma), Italy
  • B.B. Baricevic, R. Cerne, G. Jug
    I-Tech, Solkan, Slovenia
  • M. Diomede
    Sapienza University of Rome, Rome, Italy
  • P.N. Dominguez
    Menlo Systems GmbH, Martinsried, Germany
  ELI-NP is a linac based gamma-source in construction at Magurele (RO) by the European consortium EuroGammaS led by INFN. Photons with tunable energy and with intensity and brilliance well beyond the state of the art, will be produced by Compton back-scattering between a high quality electron beam (up to 740 MeV) and a 515 nm intense laser pulse. Production of very intense photon flux with narrow bandwidth requires multi-bunch operation at 100 Hz repetition rate. A total of 13 klystrons, 3 S-band (2856 MHz) and 10 C-band (5712 MHz) will power a total of 14 Travelling Wave accelerating sections (2 S-band and 12 C-band) plus 3 S-band Standing Wave cavities (a 1.6 cell RF gun and 2 RF deflectors). Each klystron is individually driven by a temperature stabilized LLRF module for a maximum flexibility in terms of accelerating gradient, arbitrary pulse shaping (e.g. to compensate beam loading effects in multi-bunch regime) and compensation of long-term thermal drifts. In this paper, the whole LLRF system architecture and bench test results, the RF reference generation and distribution together with an overview of the synchronization system will be described.  
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WEPAL036 Implementation of CSNS RCS Beam Injection and Extraction Modes in Timing System extraction, injection, linac, kicker 2247
  • P. Zhu, M.Y. Huang, D.P. Jin, G. Lei, G.L. Xu, Y.L. Zhang
    IHEP, Beijing, People's Republic of China
  • L. Wang
    CSNS, Guangdong Province, People's Republic of China
  Funding: Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China; Dong guan Neutron Science Center, Dong guan 523803, China
Based on the physical design of the accelerator and the demand of the beam research, we designed four RCS beam injection modes and two RCS beam extraction modes, each of which corresponds to a series of specific timing for the accelerator. RCS beam injection and extraction modes are implemented on "VME + customized boards" hardware platform. In this paper, we will introduce the design and implementation of RCS beam injection and extraction modes as well as the RCS timing requirements and implementation in detail.
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WEPML051 Improvement of the Chopper System for rf Deflector at the J-PARC Linac controls, cavity, linac, operation 2816
  • K. Futatsukawa, Z. Fang, Y. Fukui
    KEK, Ibaraki, Japan
  • Y. Sato
    Nippon Advanced Technology Co., Ltd., Tokai, Japan
  • S. Shinozaki
    JAEA/J-PARC, Tokai-mura, Japan
  In the J-PARC linac, the RF deflector has been operated to kick the wasted beam and to shape the intermediate-pulse like the comb structure. Then about 50% of the beam current is removed by leading the scraper and the rest beam current is injected to the downstream synchrotron ring RCS. The fast rising time and falling time, the cavity with low loading Q value in the chopper system are required to decrease the incomplete kicked beam. However, there was the ringing of the RF field on the chopper cavity, and it influenced the beam rising time. The chopper controllers, which has the fast RF -switch to make the particular RF according to the intermediate-pulses, were improved for the RF falling time by outputting short pulses with inverting phase. The beam study for the new system was successfully done. In this paper, I would like to introduce this system and to show the results of the beam study.  
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THPAL046 Energy-Savings for the TPS Booster RF System at the NSRRC in Taiwan controls, booster, injection, storage-ring 3748
  • F.-T. Chung, F.Y. Chang, L.-H. Chang, M.H. Chang, S.W. Chang, L.J. Chen, Y.T. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh, T.-C. Yu
    NSRRC, Hsinchu, Taiwan
  In this paper, we discuss an energy-savings control sys-tem for the Taiwan Photon Source (TPS) booster RF sys-tem. During top-up storage ring operation, a timing con-trol is activated to reduce the booster RF transmitter en-ergy consumption when no injection is required. When-ever injection into the TPS storage ring is needed, the booster RF transmitter is immediately adjusted to operat-ing conditions. This timing-control system will save an energy of 380, 000 kWh annually.  
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THPAL082 Development of a New Modular Switch Using a Next-Generation Semiconductor power-supply, pulsed-power, ISOL, kicker 3841
  • T. Takayanagi, K. Horino, T. Ueno
    JAEA/J-PARC, Tokai-mura, Japan
  An ultra-high-speed short pulse switch for high power have been developed by using SIC - MOSFET which is one of next generation semiconductors. Semiconductor switches using SIC-MOSFETs are expected to replace the thyratron, and they are composed of circuits in which many semiconductor switches are multiplexed in series and parallel for high power. Semiconductor switches using SIC-MOSFETs are expected to replace the thyratron, and they are also designed by connecting many semiconductor switches in parallel-series. To realize a low switching noise, it is common to form a symmetrical circuit. However, as the number of parallel connections increases, the circuit length between input and output becomes longer, so the output waveform is distorted due to any timing jitter or level fluctuation. Therefore, we propose a radially symmetric type of a module switch which does not cause level fluctuation due to the timing jitter by equalizing the circuit length independently of the number of semiconductor switches. The design and preliminary test results of two types of switch circuits, radially symmetric type and line symmetric type are presented here.  
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THPAL151 Progress in Understanding Breakdown Characteristics of X-Band Choke-Mode Structures cavity, experiment, HOM, operation 4002
  • X.W. Wu, D.Z. Cao, H.B. Chen, J. Shi, H. Zha
    TUB, Beijing, People's Republic of China
  • T. Abe, T. Higo, S. Matsumoto
    KEK, Ibaraki, Japan
  Funding: National Natural Science Foundation of China (Grant No. 11135004).
As one of the higher-order-mode (HOM) damping structures, X-band choke-mode accelerating structures had been studied for several years. However, the breakdown characteristics of the X-band choke are still unknown. Five different single-cell choke-mode accelerating structures and one reference structure were designed, fabricated and high-gradient tested to study the related RF breakdown characteristics. The absence of field emission current flash was proposed to be the sign of breakdowns occurring inside the choke, this was verified by the post-mortem observation. Evaluation of the breakdown rate revealed that there is memory effect with pulse width and electric field. The breakdown rate in a single RF pulse did not have the 5th order pulse width and 30th order electric field dependency predicted by the empirical formula.
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THPMK043 Timing Stability at LCLS cavity, laser, linac, FEL 4381
  • F.-J. Decker, R.N. Coffee, W.S. Colocho, J.M. Glownia, K. Gumerlock, B.L. Hill, T.J. Maxwell, J. May
    SLAC, Menlo Park, California, USA
  The beam stability of the LCLS (Linac Coherent Light Source) has increased substantially over the years. Transversely it is a fraction of the beam size. The energy jitter was reduced from five times the energy spread to a fraction of it. Only the timing jitter is left. It got improved during the energy jitter reduction, but typically left alone. So we have five dimensions of the six-dimensional phase space covered with feedbacks and special 60-Hz jitter setups which eliminate the difference between every other pulse, but not for the general timing setup. We describe a scheme with the RF of the XTCAV, which could be used for other setups like lasers.  
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