View source for DR dipole (15 deg)

A new 15 deg bend magnet was designed to operate at higher beam energy and to minimize higher order multipoles.

== Design ==
;Jay's modeling which includes canting coils +/- 0.8 deg to achieve equal focusing in both planes [https://jlabdoc.jlab.org/docushare/dsweb/Get/Document-207097/19-041.pdf JLab-TN-19-041]  [[media:19-041.pdf]]

; ME drawings which were used by Milhous to fabricate the coil (square wire, Feb 11, 2020)
We went through both square and round wire designs; finally used a round wire

::- Dipole fixture [[media:200KeVYDipoleFixture-JL0087295.pdf]]
::- Dipole winding [[media:200KeVYDipoleCoil-JL0087835.pdf]]

; Shims for canted operation
::- [[media:MDR_shim.pdf]]
::- [https://www.mcmaster.com/catalog/127/3509 Laminate shim stock] (2 mil/layer * 31 layers = 64 mil laminate, where each 2 mil layer can be peeled away)
::- 28 mil shim needed for 1.688 deg angle between upper and lower coils (top 0.844 deg cw, bottom 0.844 deg ccw)
::- each 2 mil layer of shim corresponds to a change in this angle by 0.048 deg (e.g. 28=>30 mil reduces angle to 1.640 deg, or 28=>26 mil increases angle 1.736 deg)
::- We have 6 shims on hand, that is, we may choose up to 6 angles

== Fabrication ==

; Milhous was awarded fabrication of two DR magnets (four halves).

* Oct 5, 2020 (M. Beck) First half received from Milhous last week. The dimension inspection of the aluminum coil fixture is correct. Electrical testing, hipot and surge testing at 500V is completed, all meet JLAB acceptance criteria.   Can not confirm turn count is correct with this kind of winding process and there is no additional coil to conduct coil comparison testing. It might be reasonable to assume the wire count is correct as we only have one halve section and no mapping can occur until we receive the next halve.  Coil appearance looks reasonable for the fashion used for fabrication/winding. We just need 3 more halve sections to put these magnets together, after QA is completed on the additional 3 articles we will begin mapping.  Milhous winding another half, will shop to JLab ASAP, within a week or so

== Measurments ==

* MMF measurements of DR001 - [[media:Dipole_15deg_DR001_FieldMap.txt]]
* MMF measurements of DR002 (installed at CEBAF) - [[media:Dipole_15deg_DR002_FieldMap.txt]]
* Riad's analysis of the two dipoles - [[media:Dipole15deg_FieldMap.pptx]]

(January 13 2021 - MMF coil measurements)

;Magnet DR01
TOP-SN#01
L/60Hz=1.617mH
DCR=915.9 milliohm
BOTTOM-SN#02
L/60Hz=1.563mH
DCR=887.1 milliohm

; Magnet DR02
TOP-SN#03
L/60Hz=1.527mH
DCR=881.5 milliohm 
BOTTOM-SN#04
L/60Hz=1.540mH
DCR=887.3 milliohm

From Jay - The ratio of inductances suggests a 1.7% turns discrepancy while resistance suggests 3.2% top vs bottom in DR01.  (inductance goes as N^2, resistance as N).   I suggest using the DR02 in the machine.

== Intermediate design exchanges ==

; Archive of intermediate drawings
Oct 18, 2019 - Final 15 deg coil fixture
* Drawing [[media:191018_15_COIL_FIXTURE.pdf]]

; Specifications and markup documents
Oct 23, 2019 - Jay mark-up for low- and high- energy coil
* Drawing [[media:191023_Jay_dwg_markup.pdf]]
* Specification [[media:191023_Jay_spec.docx]]