View source for QW Wien quadrupoles (200 kV upgrade)

New Wien quadrupoles have been designed to operate at higher 200 kV energy but also with improved magnetic and mechanical design.

== What to consider in a new design? ==
; Requirements
* Larger ID air-core quad that could fit over 2-3/4" flange
* Longer quad to provide more field strength (required values under study; appears we need at least 33% increase over existing QW @ 3A)
* Quads have to be bakeable to 250C; as they're still captured when vacuum assembly made-up before beam line bake out
* Operate w/ <10 A idea, so can use existing trim cards (like those presently used)

; Darmstadt triplet
:B. Steiner et al., Recent Simulation Results of the Polarized Electron injector (SPIN) of the S-DALINAC [https://www.researchgate.net/publication/228564835_Recent_Simulation_Results_of_the_Polarized_Electron_injector_SPIN_of_the_S-DALINAC] ([[media:200204_Triplet.pdf]])
:J. Benesch, Modeling the Darmstadt quad triplet [https://jlabdoc.jlab.org/docushare/dsweb/Get/Document-200405/JLAB-TN-19-025.pdf JLAB-TN-19-025]

== New Design ==

; Design studies
* Lakshmi's slides for Sep 17, 2020 Weekly meeting [[ media:QW Magnet design-V03-Lakshmi-20200913.pdf]]
* Lakshmi's slides from Aug 31, 2020 design meeting [[media:QW Magnet design-V02-Lakshmi-20200831.pdf]]
* Lakshmi's slides from Aug 20, 2020 design meeting [[media:QW Magnet design-V01-Lakshmi-20200819.pdf]]

; Final design report
* EM design [[media:EM design-QW-V01-210520.docx]]

; Drawings
* Wien crosses - [[media:JL0091130-0222-03, QW 6-way cross sketch for quote-1.pdf]]

; Performance
* Measurement vs. Design [[media:MEG0002021-R004-MQW magnetic mapping-V01-210521.docx]]

== Pre-existing QW's ==
; Background
* These quads are used to compensate the dipole focusing of the Wien filters.
* There is one installed on the 6-way cross upstream/downstream of each Wien filter.
* They were designed to fit on top of existing 6-way viewer cross (1.5" pipe w/ 2-3/4" flanges).
* In order to maximize the field strength they were designed w/ as small an ID as possible 2-3/4".  However, this means they're captured by the flanges which are welded on after the coils are assembled.   We'd love to eliminate this, to have a quad coil that would pass over the 2-3/4" flange.
* Their length is about 4.9", the length of the 6-way cross.   They could be longer, however, the 6-way cross abuts an 8" zero-reducer flange on the Wien filter, so a longer coil could not be perfectly symmetric on the 6-way cross.  But, that's OK.   A great way to recover field strength, I guess.

; Engineering Drawings
* Assembly drawing [[media:ACC2004000-1035 - QW QUAD-CROSS ASSEMBLY.pdf]]
* Coil drawing [[media:QW_magnet.pdf]]

; QW info
* Present operating limit is 3A
* Field measurements may exist, need to look
* Jay should have a model of the quads, a good starting place, here's info from him:
 On 3/5/2020 2:42 PM, Jay Benesch wrote:
 > IR of QW model 1.375".  Cross section 0.3" radial by 0.22" azimuthal. 
 > 4.92" overall length.  35 AT in my 1A model, not 36 T.  0.55 G-cm 
 > dipole, 22.57 G, both evaluated at 1 cm radius.  With 1 A and 36 T, 
 > 23.21 G quadrupole at 1 cm radius.