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Photon Linear Collider Gamma-Gamma Summary

Description: High energy photon - photon collisions can be achieved by adding high average power short-pulse lasers to the Linear Collider, enabling an expanded physics program for the facility. The technology required to realize a photon linear collider continues to mature. Compton back-scattering technology is being developed around the world for low energy light source applications and high average power lasers are being developed for Inertial Confinement Fusion.
Date: February 27, 2012
Creator: Gronberg, J
Partner: UNT Libraries Government Documents Department

Photon Collider Physics with Real Photon Beams

Description: Photon-photon interactions have been an important probe into fundamental particle physics. Until recently, the only way to produce photon-photon collisions was parasitically in the collision of charged particles. Recent advances in short-pulse laser technology have made it possible to consider producing high intensity, tightly focused beams of real photons through Compton scattering. A linear e{sup +}e{sup -} collider could thus be transformed into a photon-photon collider with the addition of high power lasers. In this paper they show that it is possible to make a competitive photon-photon collider experiment using the currently mothballed Stanford Linear Collider. This would produce photon-photon collisions in the GeV energy range which would allow the discovery and study of exotic heavy mesons with spin states of zero and two.
Date: November 3, 2005
Creator: Gronberg, J & Asztalos, S
Partner: UNT Libraries Government Documents Department

Photon Collider Technology Overview

Description: The photon collider option requires the generation of large amounts of laser power to drive the Compton scattering. The selection of the superconducting RF for the baseline of the ILC makes a recirculating solution attractive. A baseline for a recirculating cavity for the photon collider has been developed by a team [1, 2] at DESY/Zeuthen and the Max Born Institute. Similar cavities at much lower scale are being developed for laser wire and Compton polarimeter applications. The current status of the laser technology and a proposal for future development are reviewed. The impact of the {gamma}{gamma} experiment on the accelerator and detector is also discussed.
Date: July 28, 2005
Creator: Gronberg, J
Partner: UNT Libraries Government Documents Department

Development of High Average Power Lasers for the Photon Collider

Description: The laser and optics system for the photon collider seeks to minimize the required laser power by using an optical stacking cavity to recirculate the laser light. An enhancement of between 300 to 400 is desired. In order to achieve this the laser pulses which drive the cavity must precisely match the phase of the pulse circulating within the cavity. We report on simulations of the performance of a stacking cavity to various variations of the drive laser in order to specify the required tolerances of the laser system. We look at the behavior of a simple four mirror cavity as shown in Fig. 1. As a unit input pulse is applied to the coupling mirror a pulse begins to build up in the interior of the cavity. If the drive pulses and the interior pulse arrive at the coupling mirror in phase the interior pulse will build up to a larger value. The achievable enhancement is a strong function of the reflectivity of the cavities. The best performance if attained when the reflectivities of the input coupler is matched to the internal reflectivities of the cavity. In Fig. 2 we show the build up of the internal pulse after a certain number of drive pulses, assuming the input coupler has a reflectivity of 0.996 and the interior mirrors have 0.998 reflectivity. With these parameters the cavity will reach an enhancement factor of 450. Reducing the coupler reflectivity gives a faster cavity loading rate but with a reduced enhancement of the internal pulse. The enhancement as a function of coupler reflectivity and total internal cavity reflectivity is shown in Fig. 3. The best enhancement is achieved when the coupling mirror is matched to the reflectivity of the cavity. A coupler reflectivity just below the internal cavity reflectivity minimizes the required ...
Date: May 17, 2010
Creator: Gronberg, J; Stuart, B & Seryi, A
Partner: UNT Libraries Government Documents Department

High Average Power Lasers for the Photon Collider

Description: The idea to convert an electron collider into a high energy photon collider has existed for several decades. A key technological limitation to realizing this idea is the need to create a large amount of laser power to drive the Compton back-scattering. A concept to reduce the required laser power using a recirculating cavity has been proposed. We describe a concept for a laser architecture that could drive such a cavity.
Date: April 29, 2009
Creator: Stuart, B; Gronberg, J & Seryi, A
Partner: UNT Libraries Government Documents Department

Prototyping of the ILC Baseline Positron Target

Description: The ILC positron system uses novel helical undulators to create a powerful photon beam from the main electron beam. This beam is passed through a titanium target to convert it into electron-positron pairs. The target is constructed as a 1 m diameter wheel spinning at 2000 RPM to smear the 1 ms ILC pulse train over 10 cm. A pulsed flux concentrating magnet is used to increase the positron capture efficiency. It is cooled to liquid nitrogen temperatures to maximize the flatness of the magnetic field over the 1 ms ILC pulse train. We report on prototyping effort on this system.
Date: February 29, 2012
Creator: Gronberg, J; Brooksby, C; Piggott, T; Abbott, R; Javedani, J & Cook, E
Partner: UNT Libraries Government Documents Department

RADSRC/Monte Carlo Code Interface Manual

Description: RADSRC is a library for calculating gamma ray distributions. An initial material specification is aged and the daughter isotopes calculated to create the complete spectrum. RADSRC can be linked into, initialized, and called from other programs. This document specifies how to do this in GEANT4, COG and MCNP(X).
Date: March 23, 2007
Creator: Hiller, L; Gronberg, J; Gosnell, T & Wright, D M
Partner: UNT Libraries Government Documents Department

Source and Background Gamma-ray Spectra

Description: For this study, we have made spectra and integral count rate estimates for a trivial detector configuration with a variety of unclassified gamma-ray sources. The source/background spectra and absolute flux are taken from cumulative distribution files created from MCNP simulations prepared by Ron Wurtz and Mike Frank. The simulated objects were criticality assemblies (test setups to develop benchmarks for establishing safety margins in handling fissile material) taken from the International Handbook of Evaluated Criticality Safety Benchmark Experiments (Nuclear Energy Agency, 2001). These objects were placed inside a 30 cm box with packing material that corresponds to roughly 0.5 radiation lengths (X{sub 0}). The simulations were repeated with an additional 7cm thick steel box enclosure.
Date: October 21, 2005
Creator: Gronberg, J; Johnson, S; Lange, D & Wright, D
Partner: UNT Libraries Government Documents Department

Computer Calculations of Eddy-Current Power Loss in Rotating Titanium Wheels and Rims in Localized Axial Magnetic Fields

Description: We have performed preliminary computer-based, transient, magnetostatic calculations of the eddy-current power loss in rotating titanium-alloy and aluminum wheels and wheel rims in the predominantly axially-directed, steady magnetic fields of two small, solenoidal coils. These calculations have been undertaken to assess the eddy-current power loss in various possible International Linear Collider (ILC) positron target wheels. They have also been done to validate the simulation code module against known results published in the literature. The commercially available software package used in these calculations is the Maxwell 3D, Version 10, Transient Module from the Ansoft Corporation.
Date: May 15, 2006
Creator: Mayhall, D J; Stein, W & Gronberg, J B
Partner: UNT Libraries Government Documents Department

Design of a Pulsed Flux Concentrator for the ILC Positron Source

Description: The Positron Source for the International Linear Collider requires an optical matching device after the target to increase the capture efficiency for positrons. Pulsed flux concentrators have been used by previous machines to improve the capture efficiency but the ILC has a 1 ms long pulse train which is too long for a standard flux concentrator. A pulsed flux concentrator with a 40 ms flat top was created for a hyperon experiment in 1965 which used liquid nitrogen cooling to reduce the resistance of the concentrating plates and extend the lifetime of the pulse. We report on a design for a 1 ms device based on this concept.
Date: May 17, 2010
Creator: Gronberg, J; Abbott, R; Brown, C; Javedani, J; Piggott, W T & Clarke, J
Partner: UNT Libraries Government Documents Department

HIGGS PHYSICS WITH A GAMMA GAMMA COLLIDER BASED ON CLIC 1*.

Description: We present the machine parameters and physics capabilities of the CLIC Higgs Experiment (CLICHE), a low-energy {gamma}{gamma} collider based on CLIC 1, the demonstration project for the higher-energy two-beam accelerator CLIC. CLICHE is conceived as a factory capable of producing around 20,000 light Higgs bosons per year. We discuss the requirements for the CLIC 1 beams and a laser backscattering system capable of producing a {gamma}{gamma} total (peak) luminosity of 2.0 (0.36) x 10{sup 34} cm{sup -2} s{sup -1} with E{sub CM}({gamma}{gamma}) 115 GeV. We show how CLICHE could be used to measure accurately the mass, {bar b}b, WW and {gamma}{gamma} decays of a light Higgs boson. We illustrate how these measurements may distinguish between the Standard Model Higgs boson and those in supersymmetric and more general two-Higgs-doublet models, complementing the measurements to be made with other accelerators. We also comment on other prospects in {gamma}{gamma} and e{sup -}{gamma} physics with CLICHE.
Date: November 1, 2001
Creator: ASNER,D.; BURKHARDT,H.; DE ROECK,A.; ELLIS,J.; GRONBERG,J.; HEINEMEYER,S. et al.
Partner: UNT Libraries Government Documents Department

Design Issues for the ILC Positron Source

Description: A positron source for the International Linear Collider (ILC) can be designed using either a multi-GeV electron beam or a multi-MeV photon beam impinging on a metal target. The major design issues are: choice of drive beam and its generation, choice of target material, the target station, positron capture section, target vault and beam transport to the ILC positron damping ring complex. This paper lists the ILC positron source requirements and their implications for the design of the positron source. A conceptual design for the ILC is expected to be finished in the next two years. With emphasis on this timescale, source design issues and possible solutions are discussed.
Date: February 15, 2006
Creator: Bharadwaj, V.; Batygin, Yu.K.; Pitthan, R.; Schultz, D.C.; Sheppard, J.; Vincke, H. et al.
Partner: UNT Libraries Government Documents Department

Performance of a High Resolution Cavity Beam Position Monitor System

Description: It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {micro}rad over a dynamic range of approximately {+-} 20 {micro}m.
Date: December 18, 2006
Creator: Walston, S; Boogert, S; Chung, C; Fitsos, P; Frisch, J; Gronberg, J et al.
Partner: UNT Libraries Government Documents Department

PERFORMANCE OF A NANOMETER RESOLUTION BPM SYSTEM

Description: International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved--ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. The three BPMs are rigidly mounted inside an alignment frame on variable-length struts which allow movement in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a calibration algorithm which is immune to beam jitter. To date, we have been able to demonstrate a resolution of approximately 20 nm over a dynamic range of +/- 20 microns. We report on the progress of these ongoing tests.
Date: June 21, 2006
Creator: Walston, S; Chung, C; Fitsos, P; Gronberg, J; Meller, R; Vogel, V et al.
Partner: UNT Libraries Government Documents Department

Performance of a Nanometer Resolution BPM System

Description: International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. it is important to the ongoing ILC design effort to demonstrate that these tolerances can be achieved--ideally using beam-based stability measurements. It has been estimated that an RF cavity BPM with modern waveform processing could provide a position measurement resolution of less than one nanometer. Such a system could form the basis of the desired beam-based stability measurement, as well as be used for other specialized purposes. They have developed a high resolution RF cavity BPM and associated electronics. A triplet comprised of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. The three BPMs are rigidly mounted inside an alignment frame on six variable-length struts which can be used to move the BPMs in position and angle. they have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, they have been able to demonstrate a resolution of approximately 20 nm over a dynamic range of {+-} 20 {micro}m. They report on the progress of these ongoing tests.
Date: October 14, 2005
Creator: Vogel, V; Hayano, H; Honda, Y; Terunuma, N; Urakawa, J; Kolomensky, Y et al.
Partner: UNT Libraries Government Documents Department

Performance of a Nanometer Resolution BPM System

Description: International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. The three BPMs are rigidly mounted inside an alignment frame on variable-length struts which allow movement in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a calibration algorithm which is immune to beam jitter. To date, we have been able to demonstrate a resolution of approximately 20 nm over a dynamic range of +/- 20 microns. We report on the progress of these ongoing tests.
Date: April 24, 2007
Creator: Walston, S.; Chung, C.; Fitsos, P.; Gronberg, J.; /LLNL, Livermore; Meller, R. et al.
Partner: UNT Libraries Government Documents Department

Resolution of a High Performance Cavity Beam Positron Monitor System

Description: International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved--ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. A metrology system for the three BPMs was recently installed. This system employed optical encoders to measure each BPM's position and orientation relative to a zero-coefficient of thermal expansion carbon fiber frame and has demonstrated that the three BPMs behave as a rigid-body to less than 5 nm. To date, we have demonstrated a BPM resolution of less than 20 nm over a dynamic range of +/- 20 microns.
Date: July 6, 2007
Creator: Walston, S.; Chung, C.; Fitsos, P.; Gronberg, J.; /LLNL, Livermore; Ross, M. et al.
Partner: UNT Libraries Government Documents Department