Ralph J. Pasquinelli

Precision vector control of a superconducting RF cavity driven by an injection locked magnetron

The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRF cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.

The 4.8 GHz LHC Schottky pick-up system

The LHC Schottky observation system is based on traveling wave type high sensitivity pickup structures operating at 4.8 GHz. The choice of the structure and operating frequency is driven by the demanding LHC impedance requirements, where very low impedance is required below 2 GHz, and good sensitivity at the selected band at 4.8 GHz. A sophisticated filtering and triple down-mixing signal processing chain has been designed and implemented in order to achieve the specified 100 dB instantaneous dynamic range without range switching. Detailed design aspects for the complete systems and test results without beam are presented and discussed.

Optical correlator notch filters for Fermilab debuncher betatron stochastic cooling

Optical correlator notch filters have been installed in the Fermilab Antiproton Debuncher ring. Their main function is the improvement of system signal-to-noise ratio without degradation of system gain and phase parameters. This is turn yields faster cooling times that are compatible with the more rapid antiproton production cycles proposed for future operation. A brief discussion of cooling techniques is presented, showing the importance of the filters. In addition, the actual hardware implementation and performance results are presented.<<ETX>>

Microwave Schottky diagnostic systems for the Fermilab Tevatron, Recycler, and CERN Large Hadron Collider

A means for non-invasive measurement of transverse and longitudinal characteristics of bunched beams in synchrotrons has been developed based on high sensitivity slotted waveguide pickups. The pickups allow for bandwidths exceeding hundreds of MHz while maintaining good beam sensitivity characteristics. Wide bandwidth is essential to allow bunch-by-bunch measurements by means of a fast gating system. The Schottky detector system is installed and successfully commissioned in the Fermilab Tevatron and Recycler and CERN LHC synchrotrons. Measurement capabilities include tune, chromaticity, and momentum spread of single or multiple beam bunches in any combination. With appropriate calibrations, emittance can also be measured by integrating the area under the incoherent tune sidebands.

Implementation of stochastic cooling hardware at Fermilab's Tevatron collider

The invention of Stochastic cooling by Simon van der Meer made possible the increase in phase space density of charged particle beams. In particular, this feedback technique allowed the development of proton antiproton colliders at both CERN and Fermilab. This paper describes the development of hardware systems necessary to cool antiprotons at the Fermilab Tevatron Collider complex.

Fiber optic links for instrumentation

The author will cover the questions one might ask in selecting a transmission system in complex systems followed by the available hardware on the market. A short discussion of optical techniques and actual hardware sytems will be given. Special attention is paid to fiber optic systems. (AIP)

Bulk acoustic wave (BAW) devices for stochastic cooling notch filters

Work on replacing all existing notch filters in the PBAR source with BAW notch filters is described. Three filters have been designed and built for the debuncher, thus eliminating the fiber optic filters. These have been installed since the fall of 1990. New filters for replacing the superconducting filters in the accumulator are now under construction. The delay stability of the BAW device is on the order of 27 p.p.m. per degree centigrade for a sapphire crystal. Maintaining notch frequency spacing requires a constant temperature environment; hence, the entire unit is mounted in an oven.<<ETX>>

Snapshot Digitizer System for Fermilab Main Accelerator

The snapshot digitizer system is becoming an important diagnostic tool for the Fermilab main accelerator. This high speed data acquisition system operates at 53 MHz. Inputs to the system are various beam processors whose analog outputs may be digitized and stored in any combination of groupings; i.e. diagnostic mode, starting on any of the 1113 bunches, digitizing 1-1113 sequential bunches, with anywhere from l-9999 turns around the 4 mile accelerator between digitizations. The system can be gated on at any point of the machine cycle. One of the variations is a Beam Quality mode where each bunch of each of the 13 Booster accelerator batches is tracked and digitized on its first pass around the main accelerator, thereby showing a profile of the injected beam. The combinations of data acquisition grouping are numerous. This paper describes the hardware and timing necessary for the system to operate. Figure 1 is the system block diagram. 60 MHz 6 Bit A/D & Source Multiplexer

Performance and Upgrades of the Fermilab Accumulator Stacktail Stochastic Cooling

We report on the performance and planned upgrades to the Fermilab Accumulator Stacktail Stochastic Cooling System. The current system has achieved a maximum flux of 16.5e10/hour, limited by the input flux of antiprotons. The upgrades are designed to handle flux in excess of 40e10/hour.

Performance of the upgraded Stacktail Momentum Cooling system in the Fermilab antiproton source

Major changes in the Stacktail Momentum Stochastic Cooling system have resulted in an improved stacking rate as well as the capability to stack larger quantities of antiprotons. Both these effects result in higher initial and integrated luminosity for colliding beam physics. An over view of the changes and actual system performance will be presented.<<ETX>>