Beam Dynamics Newsletter

Provided herein are systems and methods for operating a traveling wave linear accelerator to generate stable electron beams at two or more different intensities by varying the number of electrons injected into the accelerator structure during each pulse by varying the electron beam current applied to an electron gun The electron beams may be used to generate x-rays having selected doses and energies, which may be used for cargo scanning or radiotherapy applications

Systems and methods for cargo scanning and radiotherapy using a traveling wave linear accelerator based x-ray source using pulse width to modulate pulse-to-pulse dosage

An electromagnetic wave having a phase velocity and an amplitude is provided by an electromagnetic wave source to a traveling wave linear accelerator. The traveling wave linear accelerator generates a first output of electrons having a first energy by accelerating an electron beam using the electromagnetic wave. The first output of electrons can be contacted with a target to provide a first beam of x-rays. The electromagnetic wave can be modified by adjusting its amplitude and the phase velocity. The traveling wave linear accelerator then generates a second output of electrons having a second energy by accelerating an electron beam using the modified electromagnetic wave. The second output of electrons can be contacted with a target to provide a second beam of x-rays. A frequency controller can monitor the phase shift of the electromagnetic wave from the input to the output ends of the accelerator and can correct the phase shift of the electromagnetic wave based on the measured phase shift.

Traveling wave linear accelerator comprising a frequency controller for interleaved multi-energy operation

Over the last decades, the performance disparity between processor and memory has steadily grown in computer systems, an issue commonly known as Memory Wall (WULF; MCKEE, 1995). Since Dynamic Random-Access Memory (DRAM) is the most common type of main memory in computer systems, intense research efforts have been made to improve its performance and energy efficiency. However, DRAM design space exploration comes with problems. Although cycle-accurate memory simulators can simulate timings in a very precise manner, the simulation can become extremely slow. By moving to a higher abstraction level, through the virtual prototyping method, simulation speedup can be achieved with negligible losses in accuracy. Seeing that the DRAM memory controller is a key block for the overall memory system performance, it is integrated onto the same chip of the multiple CPU cores that require access to the off-chip main memory. Therefore, in this work, schedulers of the DRAM controller were modeled with SystemC/TLM 2.0 (IEEE Computer Society, 2012) in DRAMSys (JUNG M.; WEIS; WEHN, 2015), a flexible DRAM subsystem design space exploration framework. The DRAMSys restructuring was the main technical contribution of this work. Then, the controller was simulated with different scheduling mechanisms in order to better understand the memory system bottlenecks and to investigate which scheduler provides the best compromise between characteristics, such as bandwidth, thread-fairness and energy consumption.

Early Childhood Educators' Perceptions of the use of documentation in emergent programs: issues, benefits, barriers and questions

The disclosure relates to systems and methods for interleaving operation of a standing wave linear accelerator (LINAC) for use in providing electrons of at least two different energy ranges, which can be contacted with x-ray targets to generate x-rays of at least two different energy ranges. The LINAC can be operated to output electrons at different energies by varying the power of the electromagnetic wave input to the LINAC, or by using a detunable side cavity which includes an activatable window.

Interleaving multi-energy x-ray energy operation of a standing wave linear accelerator

We describe development of semiconductor X-band high-power RF switches. The target applications are high-power RF pulse compression systems for future linear colliders. We describe the design methodology of the architecture of the whole switch systems. We present the scaling law that governs the relation between power handling capability and number of elements. We designed and built several active waveguide windows for the active element. The waveguide window is a silicon wafer with an array of four hundred PIN/NIP diodes covering the surface of the window. This waveguide window is located in an over-moded TE01 circular waveguide. The results of high power RF measurements of the active waveguide window are presented. The experiment is performed at power levels of a few megawatts at X-band.

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Development of high power X-band semiconductor microwave switch for pulse compression systems of future linear colliders

We describe the potential of semiconductor X-band RF switch arrays as a means of developing high power RF pulse compression systems for future linear colliders. We describe design methodology of high power RF switches, and scaling law which governs the relation between power handling capability and number of elements. The design and implementation of the active waveguide window is presented. The waveguide window is a silicon wafer with an array of four hundred PIN/NIP diodes covering the surface of the window. This waveguide window is located in an over-moded TE01 circular waveguide. The results of low power and high power RF measurements of the active waveguide window are presented. The high power experiment is performed at power levels of several megawatts at X-band.

Fumihiko Tamura

Papers

Development of high power X-band semiconductor microwave switch for pulse compression systems of future linear colliders

High power x-band semiconductor rf switch for pulse compression systems of future linear colliders