====== Limiting Primary Beam Power ======
Please see the [[info:limiting_beam_background|background]] page for more information about these specific devices. This page will lead you through how to limit primary beam power using the following devices.
==== Chopper ====
  - Determine needed beam power by consulting AP and/or relevant destination power limits
  - Note beam current on faraday cup D1102
  - Using current on faraday cup D1102 calculate current beam power
  - Use this formula to determine your duty factor: (Needed power)/(Current power)
  - Adjust repetition rate and pulse width to achieve needed duty factor
    - Consult with AP, sometimes they will request you use a certain rep. rate or pulse width in your calculations
  - Double check beam power with beam on D1102
  - Send!

==== Attenuators ====
  - Determine needed beam power by consulting AP and/or relevant destination power limits
  - Note beam current on faraday cup D1102
  - Using current on faraday cup D1102 calculate current beam power
  - Use this formula to determine your attenuation factor: (Current power)/(Needed power)
  - Insert attenuator(s) whose product equals your attenuation factor
  - Put beam back on D1102 and double check beam power, restart at step 5 if needed
  - Send!

==== Source Slits ====
  - Determine which source is providing primary beam
  - Determine needed beam power by consulting AP, relevant destination power limits, or users.
  - These next steps should be done simultaneously and are listed below
    - Open or close __vertical__ top and bottom source slits in 0.1mm steps
    - Wait 5 sec. between adjustments and watch beam power like a hawk
  - Adjust slits in this manner until desired beam power is reached
  * Some notes that may help you during tuning
    * It is important you ONLY touch the vertical slits
    * HPECR source has slit gap control, use this tool unless instructed otherwise

====Shane Notes====
  * Primer on CW Beam might be good to start off the chopper section
  * It'd be neat to include the "why" of peak power not being affected by the chopper, but probably not necessary here
  * We can change attenuators with beam on D1102, due to how unreliable attenuators are I would prefer a new operator to keep beam on the cup and see the changes more or less in real time, helps build intuition
  * All of these should reference the location of the pages, even if it changes in the future attenuators and slits can be hard to find for new guys
  * Slits should keep the same center, this isn't clearly relayed for ARTEMIS slits
  * Slits are used for smaller adjustments, this should be laid out more clearly