Final design for the bERLinPro main LINAC cavity

The Berlin Energy Recovery Linac Project bERLinPro is designed to develop and demonstrateCWLINAC technology for 100 mA class ERLs. High current operation requires an effective damping of higher order modes HOMs of the 1.3 GHz main linac cavities. We have studied elliptical 7 cell cavities based on a modified Cornell ERL design combined with JLab s waveguide HOM damping approach. This paper will summarize the final optimization of the end cell tuning for minimum external Q of the HOMs, coupler kick calculations of the single TTF fundamental power coupler FPC as well as multipole expansion analysis of the given modes and a discussion on operational aspects

Results and Performance Simulations of the Main Linac Design for BERLinPro

The Berlin Energy Recovery Linac Project BERLinPro is designed to develop and demonstrate CW LINAC technology for 100 mA class ERLs. High current operation requires an effective damping of higher ordermodes HOMs of the 1.3 GHz main linac cavities. We have studied elliptical seven cell cavities damped by five waveguides at the adjacent beam tubes. Eigenmode calculations for geometrical figures of merit show that the present design should allow successful cw linac operation at the maximum beam current of 100 mA 77pC bunch charge. In this paper the progress in HOM calculations to avoid beam breakup instabilities for the favored cavity structure is presente

Clinical microbeam radiation therapy with a compact source: Specifications of the line-focus X-ray tube.

Background and purpose: Microbeam radiotherapy (MRT) is a preclinical concept in radiation oncology with arrays of alternating micrometer-wide high-dose peaks and low-dose valleys. Experiments demonstrated a superior normal tissue sparing at similar tumor control rates with MRT compared to conventional radiotherapy. Possible clinical applications are currently limited to large third-generation synchrotrons. Here, we investigated the line-focus X-ray tube as an alternative microbeam source. Materials and methods: We developed a concept for a high-voltage supply and an electron source. In Monte Carlo simulations, we assessed the influence of X-ray spectrum, focal spot size, electron incidence angle, and photon emission angle on the microbeam dose distribution. We further assessed the dose distribution of microbeam arc therapy and suggested to interpret this complex dose distribution by equivalent uniform dose. Results: An adapted modular multi-level converter can supply high-voltage powers in the megawatt range for a few seconds. The electron source with a thermionic cathode and a quadrupole can generate an eccentric, high-power electron beam of several 100 keV energy. Highest dose rates and peak-to-valley dose ratios (PVDRs) were achieved for an electron beam impinging perpendicular onto the target surface and a focal spot smaller than the microbeam cross-section. The line-focus X-ray tube simulations demonstrated PVDRs above 20. Conclusion: The line-focus X-ray tube is a suitable compact source for clinical MRT. We demonstrated its technical feasibility based on state-of-the-art high-voltage and electron-beam technology. Microbeam arc therapy is an effective concept to increase the target-to-entrance dose ratio of orthovoltage microbeams