Jiang, J. Feng, G. Hu, T. Lu, Y. Pei, Y.J. Tu, X.D. Xiong, Y.Q. JACoW Publishing Geneva, Switzerland 2226-0366 978-3-95450-194-6 10.18429/JACoW-LINAC2018-MOPO118 English 242-245 MOPO118 cavity linac FEL radiation electron Contribution to a conference proceedings 2019 2019-01 https://doi.org/10.18429/JACoW-LINAC2018-MOPO118 http://jacow.org/linac2018/papers/mopo118.pdf To meet the requirement of miniaturization for high power THz radiation in the field of commercial and civil use, RF Linacs have been applied widely as beam injectors, and the Linac with collinear absorbing loads reveals the potential to achieve a tradeoff between performance and compactness. Under overall consideration of systematic conflicts, optimization choices for such Linacs involving power absorbing ability, accelerating efficiency, as well as beamline length were described in this context. Meanwhile, cold testing has been conducted to verify design parameters for the collinear absorbing loads. Furthermore, elaborated calculation of thermal power loss and integrated helical water channel cooling has been performed for the 14MeV Linac with collinear absorbing loads installed on the HUST FEL-THz, and online experiments demonstrated that both the accelerating efficiency and the water cooling performance fulfilled operation demands.