[BTeam] [New Logentry] Supplemental LASO log

[Michele Joyce]

Has this version of ORFP actually been released? Should I use the DRAFT 
version for JTABS?

On 03/28/2014 03:40 PM, freyberg at jlab.org wrote:
>
>
>   Supplemental LASO log <https://logbooks.jlab.org/entry/3277931>
>
> Lognumber 3277931 <https://logbooks.jlab.org/entry/3277931>. Submitted 
> by freyberg <https://logbooks.jlab.org/user/freyberg> on Fri, 
> 03/28/2014 - 15:37.
>
> Logbooks: 	BTLOG <https://logbooks.jlab.org/book/btlog>
> Attached Files: 	
> Latest ORFP procedure 
> <imap://erb@mail.jlab.org:993/fetch%3EUID%3E/INBOX%3E144068?header=quotebody&part=1.1.2.3&filename=optics_restore_proc_13b2.pdf>
>
> Arrived this morning to relieve Tiefenback and Yves who worked over 
> night to establish a sound setup. They had a good steup through 
> pass-2, but were stuck at that point due momentum instability. Upon 
> arrival they were in the middle of dealing with this periodic energy 
> changes when I arrived and the source proved difficult to identify. 
> The RF-power guru's arrived at 7am and identified a railed cavity 
> 1L02-2 that had no phase control. With this repaired dispersion/CS 
> tuning resumed and progress in completely pass-3 by noon was almost 
> accomplished.
>
> I benefited greatly from the work of Yves and Mike (and all the rest 
> who have gotten us to this point), specifically they identified that 
> *too strong* of an RF kick during dispersion minimization. To get the 
> required kicks, they instructed me to only use *1* RF cavity during 
> fOpt and 30Hz. This tended to yield consistent results between fOtp 
> and real-time 30Hz, which was very comforting to me.
>
> At one point in the process, an old veriosn of ORFP made its way into 
> my hands and some time was lost working with the *wrong knobs*! Please 
> make sure you are working from Rev. 13b2 of ORFP (attached). Do not 
> use an older version, do not rely on the color coding of the screens.
>
> Even with the correct knobs, I found it very challenging to get the CS 
> match into Arc6. Dispersion suppression went smoothly, but there was 
> no traction on CS X or Y with the nominal knobs. I then made the 
> decision to move forward without a CS match into Arc6, reasoning a 
> mis-match in Arc6 is after the fact. I am wiling to entertain 
> arguments as to why this is the worst decision in the history of 12GeV 
> CEBAF.
>
> We then move to the Hall-A dumplette, we found the line was in a 
> totally mis-configured state, supplies off, magnets off-loop, magnets 
> mis-configured. We steered up the line, put LAM1C on design. Minimized 
> steerers as best as possible. And started a documentation effort, 
> all-saves, viewer tour, aperature check.
> At the time of this writing, an aperture check to the Hall-A dumplete 
> is in progress. Lots of transverse aperture, energy aperature data is 
> being collected now.
>
> Several times this afternoon, trucks travelling down the South Linac 
> trip off the C100s in the South very frustrating. but for the most 
> part the Accelerator has been up more than it has been down!!!! This 
> has been absolutely crucial to making progress.
>
> At 3pm I met with the Hall-A users. The tentative plan is to continue 
> our effort, if we can re-establish beam to Hall-A by midnight, they 
> have a program that can use less than 10microAmperes over night. 
> Saturday, if we are in a position to support it, we will see how high 
> we can go with CW. Sunday Owl, Hall-A will be back to low beam 
> current. Sunday day the Hall would like to do Moeller, so in the 
> morning the LASO (Joe Grames) will assist/lead setting the Wien Filter 
> and after that the hall will start the Moller program. This means Yves 
> will have to come in well before his nominal Swing Supplemental Shift. 
> I hope we will be in a position to not need Supplemental LASO on 
> Sunday Swing, if not I need a volunteer.
>
>
>
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