Robert A. Hqrdekopf, Deputy Division Leader E&vardA. tteighway, Deputy Division Leader .*.',-.• •-•.,..•,... ^!,.v _.. _• ._ ,- •_.- 51' nds far -. jhalt LaserInitiative^i^ELf)....... r Collider. ' Physics and Special Prpjwts................ ' JS 1 -ft-" 1 j ,/ 3'"^^^^*n^^^^fl5^5^^J^^?I^^^^^^^^^^^^^' ^ — ••{ /1 Stan Schiiber, AT Division Leader Foreword Accelerator Technology Division ix hoiewoitl SSCL 4.8% AFEL/POP 7.1% APT/ATW2.10/ HPMW3.1% FEL 3.9% NPB(Other) 6.3% The division tenceiaan nous, was office; we are ES&H training. manager workload. Tltes© time in pmgrammatfc worn Acieteiali/i linisum Foreword Accelerator TiLlmalati\ DIUSIOII xi Programs and The Ground Test Acceltmtor Program ; 2 Defense Free-Electron Lasers 6 Program Development AXY Programs .; 12 A Next Generation High-Power Neutron-Scattering Facility (LANSCEII) 7.7..: ;..... 14 JAERI OMEGA Project and Intense Neutron Sources for . .. Materials Testing 16 Advanced Free-Electron Laser Initiative (AFELI) 17 Superconducting Super Collider 19 The High-Power Microwave (HPM) Program 20 Neutral Particle Beam (NPB) Power Systems Highlights 21 Industrial Partnering. 22 Programs and Program Development • The Ground Test Accelerator (GTAi Program - 300 hours of operation. The reduced H, gas How lessens the need for pumping and thereby allows for a reduction in the length of the LEBT. Off-line tests of the 4X upgrade source "<? 4 are in progress. Radio Frequency Quadrupole Introduction mutely 18 Grummari engineers and (RFQ) scientists participating in all areas of Rapid progress continued throughout GTA. We also employed 25 engineers, The RFQ has operated very reliably this \ear with the following accom- designers, and technicians from a with essentially no breakdowns during plishments. The GTA team procured number oi manpower co'.tract houses. a succession of commissioning runs and fabricated S12M of hardware. The totaling - I 000 hours. Reconditioning matching section between the radio- Injector required very short limes ranging from frequency quadrupole (RFQ) and the 0.5 min during operation lo 5 min after drift tube linac (DTL) was installed on As a result of an off-line development, a night without operation. Recondi- the beamline. Beam was accelerated, we were able to replace the small angle tioning after exposure to air takes steered, and bunched for the matching ion source (SAS) with a new 4X approximately I hour. to the DTL during a commissioning source. This source was designed with period from February to April. The a 4X larger cathode spacing that The RFQ was thoroughly evaluated fust of the DTL modules was installed, decreased the power density on the against its performance specification and in a second commissioning run electrode surfaces. This replacement and the physics design during experi- from September to November, beam resulted in a very reliable operation and ment 1B. To better understand the was accelerated and steered through the quieter currents of up to 65 inA with measured transmission we compared module. As a result of these commis- the expected design emittance. We the original beam dynamics design with sioning runs, we have now integrated have now accumulated about 3 000 a new design that includes the effect of and tested all essential elements of the hours of successful injector operation. multipoles and image currents. This Ground Test Accelerator (GTA): ion design has enabled us to understand the source, low-energy beam transport To reduce the previously observed measured transmission. (LEBTi. RFQ. intermediate matching emittance growth in the LEBT, we section (IMS i. one DTL module, three shortened the length of the LEBT in Intertank Matching Section 425-MHz tetrode amplifiers, one 850- two steps. First, we eliminated the (IMS) VIH/ klystron modulator, and the steerer coils and used the physical associated diagnostics and controls. motion of the ion source and the The IMS provides eight "knobs" to repositioning of the RFQ"s upstream optimize the matching of the RFQ We continued to fabricate, assemble, end for beam "steering." Second, we beam to the DTL entrance. Two and test off-line the DTL modules in incorporated Lambertson-type steering cavities permit bunching, debunching, parallel with our effort to fabricate, coils into the two solenoid lenses; and acceleration. Four variable field assemble, and integrate the radio- steering with these coils was very quadrupole magnets provide for frequency irf) power system. Utilities satisfactory. The kngth of the LEBT focusing and defocusing, and two such as instrumentation and control was reduced by a factor of 2 from 150 quadrupole steering magnets permit lI&Cl and power wiring, water, air. cm to 75 cm. thus reducing the ob- steering and offsetting of the beam. \uruum. and cryogenic cooling were served emittance. We achieved installed and made operational. The required matching at the RFQ entrance We had significant problems condition- 40-kW liquid hydrogen cryo plant through optimization of two solenoid ing the IMS, particularly the convo- passed its acceptance test, and the GTA and two steerer currents. luted coaxial feed line, because of control room became lulls operational. multipactoring and electrical break- In parallel with the operation of the 4X downs. We solved the problem by Because of a funding decrease from source, a 4X upgrade source was reworking line details, heating a S50M to S3UM. we had to reduce CiTA designed and fabricated. The improved segment that ran in close proximity lo personnel from an average of 220 features included a reduction of H, the cold RFQ. and incorporating people in FY I Wl to an average of 150 flow by a factor of 2 to 3. better reflected if power protection. The IMS people in FY 1492. Our industrial mechanical tolerance for predictable and feed line are now reliable: how- partnership with Grumman Aerospace precise dimensions after reassembly, ever, reconditioning time remains continues successfully, with approxi- and an enlarged cesium oven leading to longer for the IMS than for the RFQ. Act clamor Technology Division Programs and Program Development • The Ground Test Accelerator (GTA) Program The IMS was thoroughly evaluated power cryo lest bed. All 10 DTL ments made on the following: during experiment 1C. We measured modules will undergo the same test centroid steering, transverse and sequence before installation on the RFQ matching and steering longitudinal emittance. phase scans, beamline. A picture of 8 DTL modules RFQ, IMS. and DTL transmission and transmission. When we modeled in various stages of completion is DTL transverse emittance versus the beam transport for low-brightness shown in Fig. 1.1. • macropul.ie time currents, we discovered the fixed- • IMS variable field quadrupole times focusing strength of the quadrupole The first module was installed on the • IMS bwicher times steering magnets had to be reduced. beamline in vacuum vessel #1 (the • DTL times This reduction will result in a more entire 24-MeV DTL will be housed in DTL longitudinal emittance vs input "robust" behavior of the IMS. We plan two vacuum vessels). It was fully energy to grind the aperture of the steering integrated with diagnostics and controls Beam centroUL vs steering (DTL, IMS) magnets to reduce the field strength. and reconditioned in situ. Phase scans vs power f DTL, IMS) RF phase and amplitude control Drift Tube Linac (DTL) During experiment 2A, the first module verification was commissioned with the ion source, Beam jitter The two main thrusts in the DTL area RFQ, and IMS, resulting in the most X-ray calibration of DTL power included installing and commissioning complete and successful GTA commis- Slit and collector vs microstrip probe the first DTL module on the beamline sioning run thus far. The run demon- steering measurements (experiment 2A) and fabricating, strated integrated operation of all Hybrid LINDA tests assembling, and off-line testing elements of the 24-MeV accelerator. Video profile tests modules 2-10. The purpose of experiment 2A was to characterize the beam and the operation Radio Frequency (rf) Power The first module was fully assembled; of the structures, to verify the design, drift tubes were aligned at room and to prepare for beam transmission During the DTL commissioning run temperature, and the module was tuned and acceleration through all 10 DTL (experiment 2A), all elements of the rf at room temperature. This included modules. power system were operated for the tuning the cavity to 850 MHz and first time in an integrated mode. Three adjusting the couplers to achieve The operation of the 3.2-MeV accelera- tetrode amplifiers provided reliable desired axial field distribution. We tor (Fig. 1.2) was very reliable; all 425-MHz power to the RFQ (135 kW), checked room temperature alignment structures performed well. Recondi- to the first IMS cavity (.6 kW), and to and tune at the cryogenic operating tioning of the DTL module was rapid: the second IMS cavity (12 kW). One temperature of 20 K in the low-power 0.5 min without breaking the vacuum 850-MHz dual-klystron modulator cryo test bed; DTL positioners were during operation, 10 min without provided power for the first DTL also exercised, and the position change breaking the vacuum overnight, and 1 module (60 kW) and the high-power of the DTL from room to cryo tempera- hour after opening to air. The source conditioning stand. The system was ture was measured. Next, the module delivered a very quiet, reliable beam. very responsive to the daily needs of was conditioned up to 130% of the Vast amounts of data were compiled as the commissioning team and worked operating power at 20 K in the high- a result of the wide variety of measure- reliably. Fig. 1.1. Drift tube linac module satlis (Juanila Romero. AT-4). Production line in full operation; five modules complete. Accelerator Technology Division 3 uiul Hrnfinwi Dt'vcloptiienl ' Ihf Lirmnul lf\t \ttfl<r,iit>r td'I'A i S'l.