1. Collimation: Work is in early stages; 

Soltan Inst. designing high power collimators for the transfer line, 
radiation protection and waveguide duct design to ease maintenance issues.

STFC designing collimators for Linac 4 (when it is being used as SPL 
injector).

2. HOMs: 

Calculation technique is established and agrees between 3 different codes.

But what parameters to use? Highest current, HOM freq. spread, bunch 
charge variation. Frank to gather info and diseminate. Goal is to have 
enough relevant calculations performed by June 25 for the HOM workshop.

3. Field emission:

Where do the electrons go? esp. for beta=1 cavity section. Can we mitigate? 
(Nagaitsev: bears on cavity spacing, Laxdal: steerers, Galambos: Minimize 
field emission.) Who is responsible? Assign to which WG?

4. Coupler configuration perturbs the beam?