LINAC4 LEBT beam size and emittance diagnostics F.Roncarolo Thanks to: J.Lettry, JB Lallement Review LIU/BI for beam size – 22 Nov 2017

Introduction L4 LEBT (tunnel and source test stand) equipped with diagnostics tank hosting H/V SEM grid + FC SEM grid usage limited to 100us pulse length with nominal bema parameters L4 source test stand equipped with slit-grid emittance meter Extensively used Position in the LEBT changed w.r.t. original design Doubts about suppression (effectiveness and uniformity) of the secondary electrons emerging from the wires Review LIU/BI for beam size – 22 Nov 2017 – FR – LIU-L4

L4 and source test stand LEBT diagnostics V grid Faraday Cup H grid Solenoid1 BCT Beam Solenoid2 Wire grid H and V slit Beam Review LIU/BI for beam size – 22 Nov 2017 – FR – LIU-L4

LEBT grids – broken wires Review LIU/BI for beam size – 22 Nov 2017 – FR – LIU-L4

Possible improvement upgrades Beam profile (and possibly emittance) monitor standing full pulse length (up to 1 ms in the LEBT?). Will study various options Change grid wires for bands: need to verify thermal response and limits BTV screen: likely prone to fast ageing, not suitable for time resolving along the pulse Allison scanner (next slide). No development started. Test stand Slit-Grid EM Discussing improvement of secondary electrons suppression via biased frame (as we have in most wire grids systems)  during 2018? Will test slit + LEBT grid (not EM grid) scans Review LIU/BI for beam size – 22 Nov 2017 – FR – LIU-L4

Allison Scanner ESS TRIUMF Review LIU/BI for beam size – 22 Nov 2017 – FR – LIU-L4

Possible future requests from ABP and/or OP Port to L4 tunnel what developed for test stand (e.g. Allison scanner) New RFQ at test stand  new diagnostics for MEBT Additional instrumentation for L4 tunnel MEBT Nothing specified/defined yet Review LIU/BI for beam size – 22 Nov 2017 – FR – LIU-L4