[Tgun] GTS Photogun Beam Structure

[Matt Poelker]

But you don't mind that the tgun will pulse at a different rep rate, right?


On 6/22/2018 9:22 AM, Riad Suleiman wrote:
> Hello,
>
> These are the GTS beam structures used with the photogun:
>
> 1. CW Beam for high current runs: Micro structure of 374.25 MHz, 50 ps.
>
> 2. Tune Beam for Harp: Macro structure of 60 Hz, 250 us. The nominal 
> average beam current during a harp scan is 100 nA. This gives a peak 
> current during the 250 us of about 0.1*1/(60*0.000250) = 6.7 uA.
>
> 3. Viewer Limited Beam for Viewers (YAG): Macro structure of 60 Hz, 4 
> us. The nominal average beam current on viewer is 2 nA. This gives a 
> peak current during the 4 us of about 0.002*1/(60*0.000004) = 8.3 uA.
>
> Notes:
> 1. We use a Beam Sync signal that goes to the laser table to generate 
> the beam macro structure. This signal also goes to the harp to trigger 
> the readout. Another copy goes to the camera of the third viewer. Of 
> the three viewers, only the third one has a camera with an external 
> trigger. We are planning to run at 10 Hz this summer and will find out 
> if there is any issues related to running at frequencies other than 60 
> Hz.
>
> 2. The Harp ADC records only one sample at approximately the middle 
> point of the 250 us beam pulse. Thus, reducing the width of the Tune 
> Beam may require other changes to Harp readout.
>
> Yours,
> Riad.
>