Richard R Smith has a PhD in Engineering Science from Caltech and has held various positions related to accelerator physics and engineering. He has experience managing projects involving X-ray detectors, medical accelerators, and research accelerators. Some of his work includes developing real-time beam diagnostics techniques and applying error functions to accelerator data analysis.

1. INTRODUCING RICHARD R SMITH

2. Experimental and Computational Improvements to Accelerator Diagnostics

3. SUMMARY OF MY EDUCATION BS, Physics, MIT PhD, Engineering Science, Cal. Tech.

4. Positions Held Medical Physicist at Siemens: data collection and sales support Other jobs as “staff physicist” Also Project Manager jobs

5. Project Manager for: Xray mine detector, went to Sandia Paper disposable gown sterilizer for Sweden 10 MeV S band research accelerator for Saclay Nuclear Lab

6. Organizational Experience Years in national magnetic fusion Years in industrial electron accelerators including L, S, & X band microwave powered accelerators, for medical treatment and sterilization

7. Unusual Accelerator Work Some 300 kV DC machines for plastic processing, 130 pulsed kV for imaging Short pulse microwave work at Phys. Intl.

8. D-beam fusion reaction species diagnostic Purpose: determine relative fractions of three ion species accelerated in a neutral beam for heating fusion experiments.

9. D-beam fusion reaction species diagnostic Approach: Collect some of the nuclear reaction products of the high energy deuterons with the slow-moving gas in the “neutralizer” section.

10. D-beam fusion reaction species diagnostic Result: Got the predicted flux, made plausible estimates of species mix, published.

11. Neutral beam fusion diagnostic publication

12. Geometry of D-D diagnostic

13. Curve fitting of proton spectra

14. Fusion product spectra

15. Real-Time Diagnostics Patented beam pulse width control for plastic processing Use of “Two Plate” real-time energy diagnostic for research accelerator for Pune, India Patent on real-time energy-like diagnostic for in-line medical accelerator

17. “ Two Plate” real-time energy diagnostic Used for research accelerator for Pune, reported in EPAC 2004 Calculate the expected currents stopped in two metal plates (including backscatter), then display both channels on an oscilloscope The ratio vs time can be used to estimate the beam energy: precise for monoenergetic beams, else “effective”

18. Calculation geometry of 2 Plate E(t)

19. Calculated Current Ratio vs MeV

20. The two-plate method was used for tuning in this work for EPAC04

21. Patent on real-time energy-like diagnostic Most therapeutic electron accelerators used for cancer therapy have bending magnets to select the beam energy The Accuray system is very compact and is straight-through, allowing some ambiguity in the beam’s energy Without risking a delicate insulating beam break, one can still separate the high energy fraction of the beam and infer E

22. Energy monitoring patent United States Patent 7,391,849Smith June 24, 2008 Energy monitoring target for x-ray dose-rate control Abstract A target structure for an electron linear accelerator converts energy in an electron beam to x-rays and provides for the monitoring and control of the effective energy of the electron beam by collecting and processing a residual current in the target structure. Inventors: Smith; Richard R. (San Ramon, CA) Assignee: Accuray Incorporated (Sunnyvale, CA) Appl. No.: 11/411,259 Filed: April 25, 2006Current U.S. Class:378/109 ; 378/101 Current International Class: H05G 1/34 (20060101) Field of Search: 378/65,119,121,137,138,109,110,113 250/305,393,396R,398,492.1,492.3,505.1 600/407,411

23. Calculations for Accelerators Error functions for depth-dose & beam profile Post-processor for EGUN output Simulation of accelerators and electron guns

24. Error functions: useful additions to data analysis In general, curve-fitting smooths out noise AND provides convenient parameters for tabulating and optimizing results Using Excel spreadsheets and its “SOLVER” function permit arbitrary fits

25. Advantages to Error Functions The standard “canned” fitting functions are not good matches to many data sets Error functions can be combined to produce positive-definite, bounded approximations to many data sets Numerical approximations in the WPA mathematical compendium by Abramowitz and Stegun allow easy evaluation of error functions

26. Error functions applied to depth-dose & beam profile. Two different applications: Compare measured penetration with that of known energies to estimate electron energy Determine the alignment of an elliptical electron beam on “trident” wire sensors

27. Error Function Calculations

28. Dosimeters on aluminum plates

29. Flexible fitting to data

30. Imatron Beam Diagnostics

31. “ Mesa Function” Example

32. Post-processor for EGUN output Using EGUN for a project needing a very long, narrow beam, it was obvious that the circa 1990 graphics gave little information Using Visual Basic, a GUI program was written to allow adjustment and display of the desired region of trajectories This was accepted for later distributions of EGUN, although a “real” programmer made the code more transportable

33. Example of improved output

34. Accelerator Simulations and Modeling Used SUPERFISH / POISSON and PARMELA to simulate X band accelerators Used EGUN, XENOS suite for injectors Tuned X band multi-cell accelerators Predicted radiation doses, thermally simulated targets, measured neutron emissions from high energy medical accels and did other engineering work