BNL, Upton, Long Island, New York, USA
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
UMAN, Manchester, United Kingdom
The CBETA project[*] is a prototype electron accelerator for the proposed eRHIC project[**]. The electron accelerator is based on the Energy Recovery Linac (ERL) and the Fixed Field Alternating Gradient (FFAG) principles. The FFAG arcs and the straight section of the accelerator are comprised of one focusing and one defocusing quadrupoles which are designed as Halbach-type permanent dipole magnets with quadrupoles component[***]. We will present the beam optics of the FFAG cell which is based on 3D field maps derived with the use of the OPERA computer code[****]. We will also present the electromagnetic design of the corrector magnets of the cell.
* http://arxiv.org/abs/1504.00588
** http://arxiv.org/ftp/arxiv/papers/1409/1409.1633.pdf
*** K. Halbach, Nucl. Instrum. Meth. 169 (1980) pp. 1-10
**** http://www.scientificcomputing.com
BNL, Upton, Long Island, New York, USA
UMAN, Manchester, United Kingdom
The Cornell-BNL Electron Test Accelerator CBETA is based on a 36 MeV superconducting linac and on a single 4-pass up/4-pass down linear FFAG return loop, for beam acceleration from 6 to 150 MeV and energy recovery. Numerical beam dynamics simulations have accompanied and eventually validated the quadrupole-doublet FFAG cell technology and parameters, and following that the complete return loop, all along the ERL lattice design process. They are key to assessing and validating the ERL optics and beam behavior over the whole acceleration/ER cycle, and in preparing future machine operation. This paper presents various of these beam dynamics studies, including start-to-end simulations.
BNL, Upton, Long Island, New York, USA
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
JLab, Newport News, Virginia, USA
Cornell University, Ithaca, New York, USA
Cornell's Lab of Accelerator-based Sciences and Education (CLASSE) and the Collider Accelerator Department (BNL-CAD) are developing the first SRF multi-turn energy recovery linac with Non-Scaling Fixed Field Alternating Gradient (NS-FFAG) racetrack. The existing injector and superconducting linac at Cornell University are installed together with a single NS-FFAG arcs and straight section at the opposite side of the the linac to form an Electron Energy Recovery (ERL) system. Electron beam from the 6 MeV injector is injected into the 36 MeV superconducting linac, and accelerated by four successive passes: from 42 MeV up to 150 MeV using the same NS-FFAG structure made of permanent magnets. After the maximum energy of 150 MeV is reached, the electron beam is brought back to the linac with opposite Radio Frequency (RF) phase. Energy is recovered and reduced to the initial value of 6 MeV with 4 additional passes. There are many novelties: a single NS-FFAG structure, made of permanent magnets, brings electrons with four different energies back to the linac. A new adiabatic NS-FFAG arc-to-straight section merges 4 separated orbits into a single orbit in the straight section.
BNL, Upton, Long Island, New York, USA
Recently a collaboration between Brookhaven National Laboratory and Cornell University was established, aiming to build the CBETA accelerator. CBETA is a 150 MeV electron test accelerator, which prototypes essential technologies of eRHIC, which is a proposed upgrade to the existing Relativistic Heavy Ion Collider (RHIC) hadron facility at Brookhaven National Laboratory. Similar to eRHIC, CBETA employs an FFAG lattice for the arcs. The arcs require short, large aperture quadrupole magnets, which are located close together. BNL has been working on a design employing permanent magnets; we show the concept and the engineering design of these magnets. Prototype magnets have been constructed recently; we report on magnetic field quality measurements and their agreement with computer simulations.
BNL, Upton, Long Island, New York, USA
Imperfection and vertical intrinsic depolarizing resonances have been overcome by the two partial Siberian snakes in the Alternating Gradient Synchrotron (AGS). The relatively weak but numerous horizontal resonances are overcome by a pair of horizontal tune jump quads. 70% proton polarization has been achieved for 2·1011 intensity. Further gain can come from maintaining smaller transverse emittance with same beam intensity. The main efforts now are to reduce the transverse emittance in the AGS and Booster, as well as robust jump quads timing generation scheme. This paper summarizes the operation results in the injectors.
UMAN, Manchester, United Kingdom
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
BNL, Upton, Long Island, New York, USA
The Cornell-BNL Electron Test Accelerator CBETA is a 4 pass up, 4 pass down energy recovery linac using Fixed-Field Alternating-Gradient (FFAG) recirculation arcs with a top energy of 150 MeV. We present lattice implemented in the tracking code pyZgoubi, with both hard edge and field map magnet versions. We also describe the recent developments in pyZgoubi such as importing lattice tables from other tracking codes.
BNL, Upton, Long Island, New York, USA
Muons, Inc, Illinois, USA
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
We present an algorithm to calculate the off-plane components of the magnetic field from the on-plane components of the magnetic field which are measured on a grid of the plane. The algorithm, which is a general one and it is not restricted on a mid-plane symmetry, is based on the Taylor series expansion of the magnetic field components in terms of the normal to the plane location. The coefficients of the Taylor series expansion are expressed in terms of the on-plane derivatives of the field components which are generated by the measured magnetic field components on the grid of the plane. The algorithm is use in the RATRACE computer code[*] and has been used[**] on a dipole magnet with median plane symmetry.
* S.B. Kowalski and H.A. Enge The Ion-Optical Program Raytrace NIM A258 (1987) 407
** N. Tsoupas et. al. Effects of Dipole Magnet Inhomogeneity on the Beam Ellipsoid NIM A258 (1987) 421-425
BNL, Upton, Long Island, New York, USA
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
Hadron cancer therapy facilities are expanding exponentially as advantages with respect to other radiation treatments are localized energy deposition at the tumor and reduction of side effects. The main problem of expansion is the high cost and large size of the facility. The largest cost is the delivery systems, especially isocentric gantries. We present first, the permanent Halbach gantry with significant reduction in cost and simplified operation as all treatment energies are transported from an accelerator to the patient through the same Fixed Field Alternating Gradient (FFAG) structure. The superconducting FFAG gantry also transports at one setting all energies required for the cancer treatment of the patient with carbon ions.