{"id":1286,"date":"2020-03-12T22:13:54","date_gmt":"2020-03-13T02:13:49","guid":{"rendered":"http:\/\/www.nuclearphysicslab.com\/npl\/?page_id=1286"},"modified":"2020-03-18T14:14:37","modified_gmt":"2020-03-18T18:14:37","slug":"plasma-betatron-coil-form-design-and-construction","status":"publish","type":"page","link":"http:\/\/www.nuclearphysicslab.com\/npl\/npl-home\/accelerators\/betatrons\/plasma-betatron-coil-form-design-and-construction\/","title":{"rendered":"Plasma Betatron Coil Form: Design and Construction"},"content":{"rendered":"\n

Author: Tim <\/em><\/p>\n\n\n\n

To round out his repertoire of accelerator projects (prompted by a need in the research community) Tim set out to build a variable energy, high intensity betatron. Specifically a plasma betatron.<\/p>\n\n\n\n

A betatron accelerates electrons by magnetic induction and demands a specific field profile.  That profile must satisfy the \u201crule of one half\u201d condition, which states that the magnetic field at the electron\u2019s equilibrium orbit must be exactly one half of the average field from the center to the equilibrium orbit.  When that condition is met the induced electric field will be matched to the magnetic field and will support stable acceleration.  This design is of a fast-pulsed single shot design.<\/p>\n\n\n\n

\"\"<\/a>
The final dimensions for locating the windings<\/figcaption><\/figure>\n\n\n\n

Since this coil form was made to be fast pulsed, consideration was taken to minimize the inductance, hence the number of windings used to shape the required field were held to an absolute minimum. <\/p>\n\n\n\n

\"\"<\/a>
PSF simulation of the coil form and note the placement of the toroidal tube.<\/figcaption><\/figure>\n\n\n\n

Iterative simulations in Poisson Superfish (PSF) were used to determine the placement of four upper and four lower hoops carrying identical currents to produce the necessary field.  The designed field carried two constraints, in addition to satisfying the \u201crule of \u00bd\u201d a weak focusing field gradient is needed to provide transverse vertical and horizontal focusing.  Once a satisfactory field was achieved, the conductor positions were translated into a mechanical model. The top and bottom halves are mechanically identical hence the windings are a mirror symmetry.  PSF modeling confirmed that fine tuning of the field profile could be effected by moving the two halves closer or further, this mainly adjusted the \u201crule of \u00bd\u201d while the weak focusing gradient was not as sensitive \u2013 which is desirable so as not to inadvertently place the EO on a transverse resonance. With a good design in hand, Jimbo proceeded to proceeded to build the coil form by cutting the acrylic formers with his laser cutter.<\/p>\n\n\n\n

\"\"<\/a>
The simulated profiles from PSF and Maxwell 3D<\/figcaption><\/figure>\n\n\n\n
\"\"<\/a>
Risers cut out on Jimbo’s laser cutter.<\/figcaption><\/figure>\n\n\n\n
\"\"<\/a>
Jimbo populating the coils.<\/figcaption><\/figure>\n\n\n\n
\"\"<\/a>
Radial running ribbon to series wire the windings.<\/figcaption><\/figure>\n\n\n\n
\"\"<\/a>
Then another return ribbon for undesired fields cancelation.<\/figcaption><\/figure>\n\n\n\n
\"\"<\/a><\/figure>\n\n\n\n
\"\"<\/a>
The completed upper and lower coil forms.<\/figcaption><\/figure>\n\n\n\n
\"\"<\/a>
Ribbon conductor series connecting the upper and lower coil forms.<\/figcaption><\/figure>\n\n\n\n
\"\"<\/a>
Early pulsed power testing, two 3uF, 20kV pulse discharge caps in parallel switched by a triggered spark gap. <\/figcaption><\/figure>\n\n\n\n
\"\"<\/a>
Triggered spark gap<\/figcaption><\/figure>\n\n\n\n
\"\"<\/a>
Observation of unintentional coupling and induction in nearby metallic loops. Over 1800 Amps peak measured in the bench table legs. The coil was quickly moved to an all-wooden platform.<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"

Author: Tim To round out his repertoire of accelerator projects (prompted by a need in the research community) Tim set out to build a variable energy, high intensity betatron. Specifically a plasma betatron. A betatron accelerates electrons by magnetic induction and demands a specific field profile.  That profile must satisfy the \u201crule of one…<\/p>\n

Read More Read More<\/span><\/a><\/p>\n","protected":false},"author":3,"featured_media":1295,"parent":151,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"advanced-sidebar-menu\/link-title":"","advanced-sidebar-menu\/exclude-page":false},"categories":[10,14,58,37],"tags":[],"_links":{"self":[{"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/pages\/1286"}],"collection":[{"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/comments?post=1286"}],"version-history":[{"count":4,"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/pages\/1286\/revisions"}],"predecessor-version":[{"id":2122,"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/pages\/1286\/revisions\/2122"}],"up":[{"embeddable":true,"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/pages\/151"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/media\/1295"}],"wp:attachment":[{"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/media?parent=1286"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/categories?post=1286"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.nuclearphysicslab.com\/npl\/wp-json\/wp\/v2\/tags?post=1286"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}