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Summary report: injection group

Description: The injector group attempted to define and address several problem areas related to the SSC injector as defined in the Reference Design Study (RDS). It also considered the topic of machine utilization, particularly the question of test beam requirements. Details of the work are given in individually contributed papers, but the general concerns and consensus of the group are presented within this note. The group recognized that the injector as outlined in the RDS was developed primarily for costing estimates. As such, it was not necessarily well optimized from the standpoint of insuring the required beam properties for the SSC. On the other hand, considering the extraordinary short time in which the RDS was prepared, it is an impressive document and a good basis from which to work. Because the documented SSC performance goals are ambitious, the group sought an injector solution which would more likely guarantee that SSC performance not be limited by its injectors. As will be seen, this leads to a somewhat different solution than that described in the RDS. Furthermore, it is the consensus of the group that the new, conservative approach represents only a modest cost increase of the overall project well worth the confidence gained and the risks avoided.
Date: January 1, 1984
Creator: Simpson, J.; Ankenbrandt, C.; Brown, B.; Hojvat, C.; Johnson, R.; Marriner, J. et al.
Partner: UNT Libraries Government Documents Department

Beam extraction from TeV accelerators using channeling in bent crystals

Description: Bent crystal channeling offers an interesting alternative for beam extraction from trans-GeV accelerators. Conventional extraction employs resonant beam blow-up coupled with electromagnetic beam deflecting channels. It is limited by the length of the available accelerator straight section. Channeling crystals require much less space. A five-step approach to applying crystal extraction in the Superconducting Super Collider (SSC) is discussed. Two steps, extraction from the 8 GeV Dubna Synchrophasotron and the 76 GeV Serpukhov accelerator, have occurred. The next possibility is extraction from a multi-hundred GeV superconducting accelerator. In the nineties the program could continue at UNK (3 TeV) and culminate at the TeV SSC. The possibilities and limitations of crystal extraction are reviewed. More information is needed on dechanneling in bent crystals including the effects of dislocations at TeV energies. Long, dislocation-free'' crystals are required. A more thorough understanding of the theory of crystal extraction is also desirable. 12 refs.
Date: August 1, 1989
Creator: Carrigan, R.A. Jr.; Toohig, T.E.; Tsyganov, E.N. (Fermi National Accelerator Lab., Batavia, IL (USA); Superconducting Super Collider Lab., Dallas, TX (USA) & Joint Inst. for Nuclear Research, Dubna (USSR))
Partner: UNT Libraries Government Documents Department

Slow extraction at the SSC

Description: Resonant slow extraction at the SSC will permit fixed-target operation. Stochastic extraction appears to be a promising technique for achieving spill times of the order of 1000 s. However, systematic sextupole error fields in the SSC dipoles must be reduced a factor of twenty from the design values; otherwise the extraction process will be perturbed or suppressed. In addition, good regulation of the SSC power supplies is essential for smooth extraction over the spill period. 10 refs., 1 fig.
Date: January 1, 1985
Creator: Colton, E.P.
Partner: UNT Libraries Government Documents Department

Experimental RFQ as injector to the CERN Linac I

Description: Since the successful development and testing of a radio-frequency quadrupole (RFQ) prototype at Los Alamos, the use of RFQs as injectors to the CERN linacs is being envisaged. As a pilot project, a 202.56-MHz RFQ for Linac I (Old Linac) is being built in close collaboration between Los Alamos and CERN. This project will be completed in about 15 months, a timescale imposed by other CERN programs. The CERN RFQ is based on the Los Alamos proven design approach, but will have to meet requirements of the existing CERN environment. The design characteristics of this accelerator are described, and some conclusions based on model work at CERN are given.
Date: January 1, 1981
Creator: Boltezar, E.; Haseroth, H. & Pirkl, W.
Partner: UNT Libraries Government Documents Department

Design of an electron beam spectral modification system

Description: We report the design of a spectral modification system (SMS) for use with the proposed NEAL linac-pulse stretcher ring, cw electron beam facility. The SMS allows tailoring of the energy distribution of electrons in beams produced by a pulsed linac operating in the transient beam loading (TBL) regime. Modification of the energy distribution of electrons injected into the pulse strecher ring will increase the duty factor of current extracted from the ring and improve the efficiency of the extraction process. Physically, the SMS consists of an anisochronous, achromatic magnetic lattice followed by a pair of traveling-wave accelerating sections. For beams in the energy range of 500 MeV to 4 GeV, TBL ripple on the energy envelope of microsecond long beam spills is expected to be reduced from 1% peak-peak to less than 0.01% while the desired width of the energy profile due to the phase extent of the microbunches in the beam spill is preserved.
Date: October 1, 1981
Creator: Sheppard, J.C.; York, R.C.; Norum, B.E. & McCarthy, J.S.
Partner: UNT Libraries Government Documents Department

Operating experience with the ALS linac

Description: The linac injector for the Advanced Light Source (ALS) at LBL was recently put into operation. Energy is 50 MeV, frequency 3 GHz. The electron gun delivers up to 6nC in a 3.0-ns bunch at 120 kV. A train of bunches is injected into a 1-Hz booster and accelerated to 1.5 GHz for storage ring injection. A magnetic analysis system is used for optimizing the linac. Measured beam properties from the gun and after acceleration in the linac are described. 9 refs., 3 figs.
Date: May 1, 1991
Creator: Selph, F. & Massoletti, D.
Partner: UNT Libraries Government Documents Department

Injection septum magnets for the Loma Linda medical accelerator

Description: The injection beamline runs over the last magnet before a long straight section and is then displaced downward 55.88 cm to the accelerator beamline. The displacement is magnetic and the final deflection onto the synchrotron orbit is by an electric kicker. The first component, the reverse septum magnet, bends the injection beam 25)degree) downward. This is followed by the injection septum (20)degree) bend upward) and the final injection kicker (5)degree) bend upward). The septum magnets produce a peak field of 3.4 K gauss at a current of 28,000 amperes within a 0.1 msec long pulse. The electric kicker produces a field of 7.3 KV/cm with a pulse length of 0.0011 msec. The septum magnets are similar to each other in construction with a bending radium of 72.7 cm. The curvature is required to increase the effective aperture. Each magnet has a single-turn copper coil bonded to a stainless steel plate for reinforcement. This eliminates insulating material, which could be subject to radiation damage, at the septum. The stainless steel plate is welded to the magnet laminations. The current is confined to the septum by the insulation between the laminations, which are a standard core material. The total septum thickness with shield is 1.227 cm. Pulsing the magnet eliminates the need for water cooling. 2 refs., 4 figs.
Date: September 22, 1987
Creator: Satti, J.A.
Partner: UNT Libraries Government Documents Department

The Brookhaven accelerator test facility injection system

Description: The Brookhaven Accelerator Test Facility (ATF) consists of a 50-MeV/c electron linac and a high-brightness RF-gun both operating at 2856 MHz. An extremely short (a few picoseconds) electron pulse with low transverse emittance is generated by the RF-gun. In order to preserve both longitudinal and transverse emittances, great care must be taken in transporting the electron beam from the RF-gun to the linac. We describe the injection line, present first- and second-order lattice studies of the injection line, and study nonlinear effects on the emittance. 11 refs., 4 figs., 4 tabs.
Date: January 1, 1989
Creator: Wang, X.J.; Kirk, H.G.; Pellegrini, C.; McDonald, K.T. & Russell, D.P.
Partner: UNT Libraries Government Documents Department

Achievement of Bevalac rapid mode switching

Description: Rapid changes of ion, intensity, beam line, and output energy between two modes have been achieved. The techniques for switching among the Bevalac's several injectors are described. Energy level limits at the output (for q/A = 1/2) are 470 to 2100 MeV/n (high power) or 50 to 1050 MeV/n (low power). Depending on specific field value differences, the total time required for a mode change is less than one minute. This mode of operation greatly improves program efficiency in interleaving medical and nuclear science programs at the Bevalac.
Date: May 1, 1985
Creator: Lothrop, F.; Stevenson, R.; Miller, R. & Alonso, J.
Partner: UNT Libraries Government Documents Department

The ATLAS positive ion injector

Description: This paper reviews the design, construction status, and beam tests to date of the positive ion injector (PII) which is replacing the tandem injector for the ATLAS heavy-ion facility. PII consists of an ECR ion source on a 350 KV platform injecting a very low velocity superconducting linac. The linac is composed of an independently-phased array of superconducting four-gap interdigital resonators which accelerate over a velocity range of .006 to .05c. In finished form, PII will be able to inject ions as heavy as uranium into the existing ATLAS linac. Although at the present time little more than 50% of the linac is operational, the indenpently-phased array is sufficiently flexible that ions in the lower half of the periodic table can be accelerated and injected into ATLAS. Results of recent operational experience will be discussed. 5 refs.
Date: January 1, 1990
Creator: Shepard, K.W.; Bollinger, L.M. & Pardo, R.C.
Partner: UNT Libraries Government Documents Department

ATA injector-gun calculations

Description: ATA is a pulsed, 50 ns 10 KA, 50 MeV linear induction electron accelerator at LLNL. The ETA could be used as an injector for ATA. However the possibility of building a new injector gun for ATA, raised the question as to what changes from the ETA gun in electrode dimensions or potentials, if any, should be considered. In this report the EBQ code results for the four electrode configurations are reviewed and an attempt is made to determine the geometrical scaling laws appropriate to these ETA type gun geometries. Comparison of these scaling laws will be made to ETA operation. The characteristic operating curves for these geometries will also be presented and the effect of washer position determined. It will be shown that emittance growth will impose a limitation on beam current for a given anode potential before the virtual cathode limit is reached.
Date: August 3, 1981
Creator: Paul, A.C.
Partner: UNT Libraries Government Documents Department

Modification of the U-line of the RHIC injection line

Description: The parameters of the U-line of the RHIC injection line with low {beta} waist are described. In that lattice, the location of SA is not dispersion free and 14 quadrupoles are needed. This line has been modified to move SA to a dispersion free region (after the 8-degree bend), the length and maximum gradient of quadrupoles have been adjusted to fit the existing quadrupole parameters and the number of quadrupoles is reduced to 12. 2 refs., 3 tabs.
Date: September 1, 1991
Creator: Xu, Jianming.
Partner: UNT Libraries Government Documents Department

Acceleration of heavy ions in the AGS and CBA

Description: A plan has been developed to inject ion beams from the Brookhaven Tandem or a cyclotron added to the Tandem into the AGS. This beam could then be injected into a relativistic heavy ion collider. The availability of many CBA components adds to the attractiveness of this proposal.
Date: January 1, 1983
Creator: Barton, M.Q.
Partner: UNT Libraries Government Documents Department

First results of proton injection commissioning of the AGS Booster synchrotron

Description: Beam performance for the injection phase of proton beam commissioning of the AGS Booster synchrotron will be presented. The beam from the 200 MeV Linac is transported through a new beam line into the Booster. This Linac-to Booster (LTB) beam line includes a 126{degree} bend and brings the injected beam onto the Booster injection orbit through the backleg of a main ring dipole magnet. Transfer of beam from the Linac to the Booster, spiralling beam and closing the orbit in the Booster ring are discussed. Injection and transport through one sector of the ring has been accomplished. 8 refs., 1 fig.
Date: January 1, 1991
Creator: Reece, R.K.; Ahrens, L.; Alessi, J.; Bleser, E.; Brennan, J.M.; Luccio, A. et al.
Partner: UNT Libraries Government Documents Department

New control techniques for extraction of bevalac beams

Description: Beams of accelerated heavy ions can now be delivered as one-second-long dc pulses with minimal fluctuations in instantaneous flux. Pulse duration can be held constant to within 1% while keeping a high non-varying extraction efficiency which minimizes pulse-to-pulse position shift in the extracted beam. In addition, differing beam intensities over several orders of magnitude can be delivered. Computer adjustment of all measurement and control devices results in linear operation over three orders of magnitude of beam intensity. Control of beam structure is accomplished by a unique combination of dual slope integrators and phase forward ''predictive'' circuits in the feedback loop.
Date: May 1, 1985
Creator: Nyman, M.; Chu, W.; Mehlman, B.; Mirer, W.; Oakley, H.; Renner, T. et al.
Partner: UNT Libraries Government Documents Department

First operation of ATLAS using the PII linac and a comparison to tandem injection

Description: The ATLAS Positive Ion Injector (PII) is designed to replace the tandem injector for the ATLAS heavy-ion facility. When the PII project is complete, ATLAS will be able to accelerate all ions through uranium to energies above the Coulomb barrier. PII consists of an ECR ion source on a 350 kV platform and a very low-velocity superconducting linac. The PII project is nearing completion. First beam from the complete system is expected in early 1992. Beam tests and experiments using a partially completed PII linac have demonstrated that the technical design goals are being met. The results of the early beam tests and first experiments will be discussed and compared to the performance of ATLAS with tandem injection. 10 refs., 2 figs.
Date: January 1, 1991
Creator: Pardo, R.C.; Bollinger, L.M.; Billquist, P.J.; Bogaty, J.M.; Clifft, B.E.; Markovich, P. et al.
Partner: UNT Libraries Government Documents Department

Performance of the Fermilab Main Ring during the 1988-89 Tevatron collider operation

Description: The Fermilab Main Ring serves as injector for the Tevatron at 150 GeV/c and as a source of 120 GeV/c protons for antiproton production. This paper discusses the Main Ring performance/emdash/intensity, reliability, and efficiency/emdash/during the present Collider run. Also discussed are questions related to emittance and emittance growth, both transverse and longitudinal, and the impact of Main Ring losses on the Collider experiments. 4 refs., 3 figs.
Date: March 1, 1989
Creator: Martin, P.S.
Partner: UNT Libraries Government Documents Department

Electron-beam generation, transport, and transverse oscillation experiments using the REX injector

Description: The REX machine at LANL is being used as a prototype to generate a 4-MV, 4.5-kA, 55-ns flat-top electron beam as a source for injection into a linear induction accelerator of the 16-MeV Dual-Axis Radiographic Hydrotest facility. The pulsed-power sources drives a planar velvet cathode producing a beam that is accelerated through a foilless anode aperture and transported by an air core magnetic lens for injection into the first of 48 linear induction cells. Extensive measurements of the time-resolved (<1-ns) properties of the beam using a streak camera and high-speed electronic diagnostics have been made. These parameters include beam current, voltage, current density, emittance, and transverse beam motion. The effective cathode temperature is 117 eV, corresponding to a Lapostolle emittance of 0.96 mm-rad. Transverse oscillations of the transported beam have been observed via a differenced B-dot technique to be about {plus minus}100 {mu}m at 245 MHz. This beam motion has been correlated via detailed rf measurements of asymmetric transverse cavity modes in the A-K gap. 7 refs., 6 figs.
Date: January 1, 1991
Creator: Carlson, R.L.; Allison, P.W.; Kauppila, T.J.; Moir, D.C. & Ridlon, R.N.
Partner: UNT Libraries Government Documents Department

Fixed-target option for the SSC

Description: Three questions addressed are: (1) is slow extraction technically and economically feasible at the SSC; (2) can gas jet targets be used parasitically to produce secondary beams; (3) how can parasitic test beams be obtained during collider operation. 15 references. (GHT)
Date: January 1, 1984
Creator: Colton, E.
Partner: UNT Libraries Government Documents Department

Control and initial operation of the Fermilab BO low. beta. insertion

Description: The operation of the Fermilab BO low ..beta.. insertion involves the coordinated control of the 4 strings of quadrupoles of the insertion itself along with several magnetic correction elements (20 dipoles for the closed orbit, 2 quad circuits for betatron tunes, 1 skew quad circuit for coupling, and 2 sextupole circuits for chromaticity). When the beam is stored at high energy, these elements must correct the errors induced by the strong superconducting quadrupoles of the insertion as the optics are smoothly changed from the fixed target configuration to the low ..beta.. state. The techniques and control programs for these manipulations and initial tests using a single coasting beam are described. 6 refs., 4 figs.
Date: June 1, 1985
Creator: Finley, D.A.; Johnson, R.P. & Willeke, F.
Partner: UNT Libraries Government Documents Department

Generation and acceleration of high intensity beams in the SLC injector

Description: A new gun pulser and substantially increased focusing have been added to the first 100 m of the SLAC linac in order to provide a pair of intense electron bunches to the SLC damping ring. Each bunch from this injector must have 5 x 10/sup 10/ electrons, an invariant emittance ..gamma..epsilon less than or equal to 1.8 x 10/sup -3/ m-rad and the pair must have an energy spread of less than 2%. Wakefield instabilities present in earlier versions of this injector have been controlled by reducing the transverse beam dimension by a factor of 3.
Date: April 1, 1985
Creator: Ross, M.C.; Browne, M.J.; Clendenin, J.E.; Jobe, R.K.; Seeman, J.T.; Sheppard, J.C. et al.
Partner: UNT Libraries Government Documents Department

Commissioning and operation of the Nuclear Physics Injector at SLAC

Description: The new Nuclear Physics Injector (NPI) approved for construction in October of 1983 was completed by September of 1984, and delivered short pulse beams for SPEAR ring checkout in mid-October. Long pulse beams of up to 1.6 microsecond length were also demonstrated. The paper describes the startup operation, reviews the performance characteristics, and discusses the beam transport optics used to deliver 1 to 4 GeV beams to nuclear physics experiments in End Station A.
Date: March 1, 1985
Creator: Koontz, R.F.; Miller, R.H.; Leger, G.K. & Iverson, R.
Partner: UNT Libraries Government Documents Department

Shielding and radiation protection at the SSRL 3 GeV injector

Description: The Stanford Synchrotron Radiation Laboratory (SSRL) Injector is comprised of a linear accelerator (linac) capable of energies {le} 150 MeV, a 3 GeV booster synchrotron, and a beam line to transport the electrons into the storage ring SPEAR. The injector is shielded so that under normal operating conditions, the annual dose equivalent at the shield surface does not exceed 10 mSv. This paper describes the shielding and radiation protection at the injector.
Date: December 1, 1991
Creator: Ipe, N.E. & Liu, J.C.
Partner: UNT Libraries Government Documents Department