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Assadi, S.

Paper Title Page
WGF01 Overview of Beam Instrumentations for High-Power Operation of the Spallation Neutron Source 439
 
  • S. Assadi
    ORNL, Oak Ridge, Tennessee
 
 

The Spallation Neutron Source (SNS) has been in commissioning and then operation since 2002. Beam Instruments for full operation and transition to beam powers of 1.0 MW and beyond needs to evolve to mostly non-intrusive, parasitically available and functioning at 30-60 Hz. High power operation necessitates careful monitoring to minimize un-controlled losses. In this paper, we discuss the overview of all diagnostics and present new improvements to, beam loss monitoring system, transverse and longitudinal laser profile monitors, introduction of laser emittance, addition of view screens at various locations and Mid-IR camera to observe electron deposit due to carbon foils at ring injection area. We also present the challenges in the ring instrumentations to have three decades of response and .01% losses.

 

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WGF04 SNS BLM System Overview: Detectors, Measurements, Simulations 453
 
  • A.P. Zhukov, S. Assadi
    ORNL, Oak Ridge, Tennessee
 
 

SNS is a 1.5 MW hadron beam facility; so the Beam Loss Monitor (BLM) system is a crucial part of MPS and an important tool for beam tuning. We have installed a number of Neutron Detectors (ND), Ionization Chambers and Photo-Multiplier Tubes (PMT) along the SNS beamline. In this paper we present the current status of equipment installed and experimental data obtained during SNS commissioning and operations. We compare several different types of BLMs and show advantages and disadvantages of every type. The losses are simulated by 3-D transport codes (GEANT4, SHIELD) for different loss scenarios and compared with experimental data. Also we discuss equipment issues like part obsolescence and our vision of next generation BLM system.

 

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WGF06 Computation of Space-Charge Effect in Allison Scanner and its Application to the Measurement of Emittance 455
 
  • T.V. Gorlov
    ORNL RAD, Oak Ridge, Tennessee
  • S. Assadi, C.D. Long, T.R. Pennisi, M.P. Stockli
    ORNL, Oak Ridge, Tennessee
 
 

Space charge effect has an impact on emittance measurement of low energy H- ion beam injected into the SNS RFQ. This paper presents numerical investigations of space charge effect of the beam on transverse emittance measurement using an Allison style scanner attached to the front-end test stand at SNS. The investigations are based on mathematical modelling the emittance measurement by the scanner taking into account space charge of the beam. We present a method of emittance data analysis that includes the modelling and allows more accurate measurements of the emittance. We also give an example of the emittance measurement with the scanner applying the developed method.

 

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WGF09 Status and Implementation of a Wideband Feedback System for e-p Instabilities in the SNS 462
 
  • C. Deibele, S. Assadi
    ORNL, Oak Ridge, Tennessee
  • M.J. Schulte, Z.P. Xie
    UW-Madison, Madison, Wisconsin
 
 

An analog wideband feedback system for damping e-p instabilities has been demonstrated at the PSR at Lansce. A mixed signal system is being developed and deployed at SNS. The status and expected performance of the of the system is discussed.

 

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