12 Steps to a Cooler Design D. Douglas

Concept Apply the same system engineering process that was used to design/build the IR Demo, IR Upgrade, UV Demo, reconfigure CEBAF for CEBAF-ER and the IR Upgrade for the DarkLight aperture test Balance risk & technical maturity of available methods to provide a cost-effective & robust system no magic, no miracles: rely on demonstrated solutions/technology when methods don’t exist, identify challenge & provide R&D plan, risk assessment, and workaround Deliverable: feasibility assessment and actionable cooler design report in < 2 years “actionable” => informs down-select List of components, locations, tolerances, sensitivities, cost ± 10%

https://userweb.jlab.org/~douglas/FEL/guide/design_process.html

“12 Step Program” A framework for making design choices… Basic system engineering: establish requirements, break design down into smaller bits. Implement configuration control from outset! Cooling requirements drive design Define source performance Constrain accelerator architecture Accelerator architecture analysis Reveals challenges (“miracles”) Provides opportunity for cost/performance optimization Reuse existing methods, technology, designs? Can organize activities as a sequence of trade studies & design tasks “trade study” = performance/risk/cost assessment of available solutions + down-select to optimum path forward

12 Step Breakdown for Cooler Design establish cooling system requirements energy, current, charge/bunch emittance, phase space configuration ("match") - transverse and longitudinal cooling rates for magnetized vs. non-magnetized beam architecture trades & cost/performance optimization linac vs. ERL vs. linac + CCR vs. ERL + CCR (cost optimum) choice of RF fundamental informed by required bunch length, need to get beam into/out of CCR source trades thermionic, photocathode, magic... X RF, DC magnetized/nonmagnetized

beam transfer system trades and design injector design merger design linac design Note: initial results from 2011-12 design iterate indicated can't get required brightness through linac, at least at 750 MHz x 1 cm rms bunch length; don't know what happens - at least longitudinally - when going to longer bunch and/or lower frequency, though notionally transverse "should get better" beam transfer system trades and design bunch to bunch, bunch train, full ring (RF loading probably precludes this)? pulsed kicker vs. RF separator based?

develop CCR design - with space charge, CSR, microbunching simulation of spent beam after cooling recovery transport design, if ERL is used S2E with cooling simulation sensitivity studies, tolerance specifications Provides basis for cost analysis & engineering design Informs project down-selection process