Difference between revisions of "HarmonicKicker-2021-06-18"

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== Beam setup and diagnostic options ==
 
== Beam setup and diagnostic options ==
  
* Assumption: bunch frequency = f_RF / 121 = f_Kicker / 7 ~ 12 MHz.
+
* Filling all kicker buckets at the same time is possible, but having to geometrically separate the beams poses unnecessary difficulties in terms of beam line optics and temporally sensitive diagnostics.
 +
** Assumption: bunch frequency = f_RF / 121 = f_Kicker / 7 ~ 12 MHz.
 
** All bunches then arrive at the same kicker phase.
 
** All bunches then arrive at the same kicker phase.
 
** The kicker phase knob selects the kick voltage.
 
** The kicker phase knob selects the kick voltage.
 +
* Depending on how much space the kicker itself needs, it may need a new beam line of its own '''or not'''.
 
* Measure kick angle with one or two BPMs downstream of the kicker. I feel like we will need two for a good determination of the tilt unless we take precautions to precisely align the launch into the kicker.
 
* Measure kick angle with one or two BPMs downstream of the kicker. I feel like we will need two for a good determination of the tilt unless we take precautions to precisely align the launch into the kicker.
 +
* The available BPMs are most likely of a non-resonant type. John and Tom agree that they should be able to detect 12 MHz, though their LPF characteristic means the signal will be down by > 40 dB.
 +
** Tom: The signal can be measured directly with a 4-ch scope (preamp if necessary). While the pulses are far too short for any scope bandwidth, they could be dispersed relatively easily.
 +
** John: There is a circuit that will turn the signal into DC, which may be prone to long-term drift but is simple.
 +
** Provided LHe + laser with this time structure are available, this should be tested ASAP.
 +
* Baseline calibration of BPM readout can be done with CW or tune beam with kicker turned off
 +
 +
* Direct emittance measurement by way of quadrupole scan + transverse profile detector (e.g., harp).
 +
** Regardless of the kick, the beam always needs to be centered in the lens.
 +
** Unless I'm missing something, this needs three steering magnets downstream of the kicker to make a chicane that sets up a parallel launch into the lens + harp system (the kicker itself being the fourth steerer).

Revision as of 13:44, 18 June 2021

We should talk about the kicker test from a broad perspective to get a realistic sense of the difficulties and options.

What we need to measure

  • Measure kick angle of HK as a function of the kicker bucket number
  • Measure emittance degradation as a function of the kicker bucket number

What we don't need to measure; correct me if I'm wrong

  • impact of ludicrous bunch charges, unless they are needed for diagnostics
  • bunch train with multiple "different" buckets filled at the same time

Beam setup and diagnostic options

  • Filling all kicker buckets at the same time is possible, but having to geometrically separate the beams poses unnecessary difficulties in terms of beam line optics and temporally sensitive diagnostics.
    • Assumption: bunch frequency = f_RF / 121 = f_Kicker / 7 ~ 12 MHz.
    • All bunches then arrive at the same kicker phase.
    • The kicker phase knob selects the kick voltage.
  • Depending on how much space the kicker itself needs, it may need a new beam line of its own or not.
  • Measure kick angle with one or two BPMs downstream of the kicker. I feel like we will need two for a good determination of the tilt unless we take precautions to precisely align the launch into the kicker.
  • The available BPMs are most likely of a non-resonant type. John and Tom agree that they should be able to detect 12 MHz, though their LPF characteristic means the signal will be down by > 40 dB.
    • Tom: The signal can be measured directly with a 4-ch scope (preamp if necessary). While the pulses are far too short for any scope bandwidth, they could be dispersed relatively easily.
    • John: There is a circuit that will turn the signal into DC, which may be prone to long-term drift but is simple.
    • Provided LHe + laser with this time structure are available, this should be tested ASAP.
  • Baseline calibration of BPM readout can be done with CW or tune beam with kicker turned off
  • Direct emittance measurement by way of quadrupole scan + transverse profile detector (e.g., harp).
    • Regardless of the kick, the beam always needs to be centered in the lens.
    • Unless I'm missing something, this needs three steering magnets downstream of the kicker to make a chicane that sets up a parallel launch into the lens + harp system (the kicker itself being the fourth steerer).