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LLNL flash x-ray radiography machine (FXR) double-pulse upgrade diagnostics

Description: When the FXR machine was first tuned on the 1980`s, a minimal amount of diagnostics was available and consisted mostly of power monitors. During the recent accelerator upgrade, additional beam diagnostics were added. The sensor upgrades included beam bugs (resistive wall beam motion sensors) and high-frequency B-dot. Even with this suite of measurement tools, tuning was difficult. For the current Double- Pulse Upgrade, beam transport is a more complex problem--the beam characteristics must be measured better. Streak and framing cameras, which measure beam size and motions, are being added. Characterization of the beam along the entire accelerator is expected and other techniques will be evaluated also. Each sensor has limitations and only provides a piece of the puzzle. Besides providing more beam data, the set of diagnostics used should be broad enough so results can be cross validated. Results will also be compared to theoretical calculations and computer models, and successes and difficulties will be reported.
Date: June 26, 1997
Creator: Ong, M.; Avalee, C.; Richardson, R. & Zentler, J.
Partner: UNT Libraries Government Documents Department


Description: The production of high-brightness particle beams calls for the development of advanced beam diagnostics. High brightness beams, meaning beams with a high density in phase space, are important for many applications, such as short-wavelength Free-Electron Lasers and advanced accelerator systems. A diagnostic that provides detailed information on the density distribution of the electron bunch in multi-dimensional phase-space is an essential tool for obtaining small emittance at a high charge. This diagnostic system has been developed at Brookhaven National Laboratory. One component of the system is the measurement of a slice emittance which provides a measurement of transverse beam properties (such as emittance) as a function of the longitudinal position. Changing the laser pulse profile of a photocathode RF gun has been suggested as one way to achieve non-linear emittance compensation and improve the brightness and that can be diagnosed by the slice emittance system. The other element of the diagnostic is the tomographic reconstruction of the transverse phase. In our work we give special attention to the accuracy of the phase space reconstruction and present an analysis using a transport line with nine focusing magnets and techniques to control the optical functions and phases. This high precision phase space tomography together with the ability to modify the radial charge distribution of the electron beam presents an opportunity to improve the emittance and apply non-linear radial emittance corrections. Combining the slice emittance and tomography diagnostics leads to an unprecedented visualization of phase space distributions in 5 dimensional phase-space and an opportunity to perform high-order emittance corrections. This should lead to great improvements in the beam brightness.
Date: November 24, 1998
Creator: BEN-ZVI,I.
Partner: UNT Libraries Government Documents Department

IPM measurements in the Tevatron

Description: Two Ionization Profile Monitors (IPMs) were installed in the Tevatron in 2006. The detectors are capable of resolving single bunches turn-by-turn. This paper presents recent improvements to the system hardware and its use for beam monitoring. In particular, the correction of beam size oscillations observed at injection is discussed.
Date: June 1, 2007
Creator: Jansson, Andreas; Bowie, K.; Fitzpatrick, T.; Kwarciany, R.; Lundberg, C.; Slimmer, D. et al.
Partner: UNT Libraries Government Documents Department

Proposal for continuously-variable neutrino beam energy for the NuMI facility

Description: The NuMI Facility was intended to be flexibly changed between 3 energies of beams, LE, ME, and HE. However, the changeover requires extensive downtime to move and realign horns and the target. We propose to implement a flexible arrangement where the target can be remotely moved in the beamline direction to change the beam energy and the horns remain fixed. In addition to having the attractive feature of keeping the horn optics fixed, the motion of the target can be performed more quickly and hence on a more frequent basis. We discuss potential increases in statistics in the high energy region, systematic cross-checks available, and the improved beam monitoring capabilities with such variable energy beams.
Date: July 1, 2006
Creator: Kostin, Mikhail; Kopp, Sacha; U., /Texas; Messier, Mark; U., /Harvard; Harris, Deborah A. et al.
Partner: UNT Libraries Government Documents Department


Description: On April 1, a new energy peak of 6.1 Bev was attained with the Bevatron. Scattered particles monitored with a counter telescope in triple coincidence gave approximately 100 counts per beam pulse. April 2s the machine was down to air to allow work on beam monitoring equipment. Test operations resumed April 5. Though the total number of accelerated particles is still small, due to low energy beam losses, some cloud chamber tracks have been observed. Several plates have been exposed for Goldhaber. Stars with up to 29 prongs have been observed. The following consists of a discussion of the administration, operation and some of the experimental techniques evolved in the use of the Cosmotron.
Date: April 6, 1954
Creator: Lofgren, E.J.
Partner: UNT Libraries Government Documents Department

CEBAF beam loss accounting

Description: This paper describes the design and implementation of a beam loss accounting system for the CEBAF electron accelerator. This system samples the beam curent throughout the beam path and measures the beam current accurately. Personnel Safety and Machine Protection systems use this system to turn off the beam when hazardous beam losses occur.
Date: December 31, 1995
Creator: Ursic, R.; Mahoney, K.; Hovater, C.; Hutton, A. & Sinclair, C.
Partner: UNT Libraries Government Documents Department

A photon beam position monitor for SSRL beamline 9

Description: We present here the concept of a simple one dimensional photon beam position monitor for use with high power synchrotron radiation beams. It has micron resolution, reasonable linearity in an inexpensive design. Most important, is its insensitivity to diffusely scattered low energy radiation from components upstream of the monitor.
Date: October 1, 1995
Creator: Cerino, J.A.; Rabedeau, T. & Bowen, W.
Partner: UNT Libraries Government Documents Department

Measurement of sub-picosecond bunch profiles using coherent transition radiation

Description: A technique for measuring the longitudinal profile of sub-picosecond electron bunches based on autocorrelation of coherent transition radiation is reviewed. The technique uses sub-millimeter/far-infrared Michelson interferometry to obtain the autocorrelation of transition radiation emitted from a thin conducting foil placed in the beam path. The theory of coherent radiation from a charged particle beam passing through a thin conducting foil is presented for normal and oblique incidence. Michelson interferometric analysis of this radiation is shown to provide the autocorrelation of longitudinal bunch profile. The details of a noninvasive technique for measuring longitudinal bunch profile using coherent diffraction radiation are discussed.
Date: May 1, 1996
Creator: Barry, W.
Partner: UNT Libraries Government Documents Department

Laser diagnostic for high current H{sup {minus}} beams

Description: Laser photodetachment can be used on high current, high energy H{sup {minus}} beams to carry out a wide variety of beam diagnostic measurements parasitically during normal operation, without having to operate the facility at either reduced current or duty cycle. Suitable Q-switched laser systems are small, inexpensive, and can be mounted on or near the beamline. Most of the proposed laser-based diagnostics techniques have already been demonstrated.
Date: January 1, 1998
Creator: Shafer, R.E.
Partner: UNT Libraries Government Documents Department

A multi-wire beam profile monitor in the AGS

Description: A multi-wire beam profile monitor which can be used to directly monitor and control the optical matching between the Booster and AGS rings has been installed and tested in the AGS. Placement of a multi-wire monitor directly in the AGS provides profile measurements taken upon injection and the first two or more revolutions of the beam. The data from such measurements can be used to determine the optical properties of the beam transport line leading into the AGS.
Date: July 1, 1997
Creator: Huang, H.; Buxton, W.; Castillo, V. & Glenn, J.W.
Partner: UNT Libraries Government Documents Department

Conceptual design of a proton polarimeter for RHIC

Description: A two-arm pion polarimeter utilizing toroidal magnets is being considered for use with the polarized protons beam at RHIC. The system will enable measurements of beam polarization at all RHIC energies from injection to flattop. This is a necessary diagnostic tool for tuning the RHIC snake magnets and other polarization controlling elements. Toroidal magnets constrain the pion trajectories allowing the device to be compact so that it can fit within the limited space available. A viable magnet design has been completed and suitable target configuration and operating scenario have been identified.
Date: December 1, 1996
Creator: Alekseev, I.; Belikov, N. & Bunce, G.
Partner: UNT Libraries Government Documents Department

1 nA beam position monitoring system

Description: A system has been developed at Jefferson Lab for measuring transverse position of very low current beams delivered to the Experimental Hall B of the Continuous Electron Beam Accelerator Facility (CEBAF). At the heart of the system is a position sensitive cavity operating at 1497 MHz. The cavity utilizes a unique design which achieves a high sensitivity to beam position at a relatively low cavity Q. The cavity output RF signal is processed using a down-converter and a commercial lock-in amplifier operating at 100 kHz. The system interfaces with a VME based EPICS control system using the IEEE, 488 bus. The main features of the system are simple and robust design, and wide dynamic range capable of handling beam currents from 1 nA to 1000 nA with an expected resolution better than 100 {mu}m. This paper outlines the design of the system.
Date: June 1, 1997
Creator: Ursic, R.; Flood, R. & Piller, C.
Partner: UNT Libraries Government Documents Department

Beam control and laser characterization for NIF

Description: The demanding energy, power, pulse shape, focusability, pointing, and availability requirements placed on the 192 National Ignition Facility (NIF) beams lead to the need for an automatic operation capability that is well beyond that of previous inertial confinement fusion (ICF) lasers. Alignment, diagnostic, and wavefront correction subsystems are integrated in an approach that, by permitting maximal sharing of instrumentation between subsystems, meets performance requirements at a reasonable cost.
Date: June 10, 1998
Creator: Boege, S. J., LLNL
Partner: UNT Libraries Government Documents Department

Beam diagnostics challenges for future FELs

Description: Designs are being developed to produce diffraction-limited sources based on storage-ring free-electron lasers (FELs) for the VUV and soft x-ray regime and linac-driven FELs in the few {Angstrom} regime. The requirements on the beam quality in transverse emittance (rms, normalized) of 1-2 {pi} mm mrad, bunch length (1 ps to 100 fs), and peak current (1 to 5 kA) result in new demands on the diagnostics. The diagnostics challenges include spatial resolution (1-10 {mu}m), temporal resolution (<100 fs), and single-pulse position measurements ({approximately}1 {mu}m). Examples of recent submicropulse (slice) work are cited as well as concepts based on spontaneous emission radiation (SER). The nonintercepting aspects of some of these diagnostics should also be applicable to high-power FELs.
Date: April 1, 1997
Creator: Lumpkin, A.H.
Partner: UNT Libraries Government Documents Department

A new optical design for the BNL isotope production transport line

Description: The 200 MeV linac at BNL has recently been upgraded. As a result, 2.5 times more average beam current can be delivered to the Brookhaven Isotope Resource Center (BIRC), formerly called BLIP, a facility which produces radionuclides and radiopharmaceutical for the medical community, and also supports a research program seeking more effective diagnostic and therapeutic agents. The optics of the beam transport line to BIRC was redesigned to (a) reduce transverse fluctuations of the beam at the target due to any linac energy fluctuations, (b) produce a flat beam distribution at the target, in order to avoid melting certain target materials, and (c) handle the higher beam intensity while keeping radiation levels low. A profile monitor was also modified to monitor the flatness of the beam using the algebraic reconstruction technique (ART). The above improvements will be described, and results of the commissioning of the line during the 1996 running period will be discussed.
Date: October 1, 1996
Creator: Kponou, A.; Alessi, J.G.; Raparia, D.; Mapes, M. & Tsoupas, N.
Partner: UNT Libraries Government Documents Department

Emittance formula for slits and pepper-pot measurement

Description: In this note, a rigid formula for slits and pepper-pot emittance measurement is derived. The derivation is based on the one- dimensional slit measurement setup. A mathematical generalization of the slit emittance formula to the pepper-pot measurement is discussed.
Date: October 1, 1996
Creator: Zhang, M.
Partner: UNT Libraries Government Documents Department