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

3. 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

4. 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

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

6. 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

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

8. 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