Fisher, A.S. Clarke, C.I. Field, R.C. Frisch, J.C. Herbst, R.T. Kadyrov, R.A. McKee, B.D. Tao, F. Welch, J.J. JACoW Geneva, Switzerland 978-3-95450-192-2 10.18429/JACoW-IBIC2017-TH1AB2 English 478-481 TH1AB2 ion detector linac radiation electron Contribution to a conference proceedings 2018 2018-03 https://doi.org/10.18429/JACoW-IBIC2017-TH1AB2 http://jacow.org/ibic2017/papers/th1ab2.pdf The first km of the 3-km SLAC linac is being replaced by LCLS-2, a superconducting linac with continuous RF and a maximum beam rate of 1 MHz. The beam will have an energy of 4 GeV and a maximum power of 250 kW, with an upgrade to 8 GeV and 1 MW in planning. The beam will be transported through the accelerator tunnel, passing over the future 1-km FACET-2 and the existing 1-km LCLS linacs, both using normal-conducting copper cavities at repetition rates of up to 120 Hz. The LCLS and LCLS-2 beams will continue together through the Beam Transport Hall to two new undulators, for hard and soft x rays. Kickers will direct individual pulses to either undulator or to a dump. The high power in the beam and potentially in cavity field emission necessitate integrating losses over 500 ms but responding within 0.1 ms. A capacitor for integration and a comparator for the threshold give a simple and robust approach over a wide dynamic range. We plan both long loss monitors covering regions of typically 100 m and point monitors. In regions with two or more beamlines, the system will attempt to determine the line that caused a loss, so that only one is shut off.