[Bteam] injector relative orbit and zero pos

[Tom Oren]

Links to Joe's talk and slides are as follows:

Talk:
http://opsntsrv.acc.jlab.org/ops_docs/online_document_files/MCC_online_files/polariized_source_operation_training_gun_to_FC1_Grames_video.wmv

Slides:
http://opsntsrv.acc.jlab.org/ops_docs/online_document_files/MCC_online_files/polariized_source_operation_training_gun_to_FC1_Grames_slides.pdf


On 4/19/2011 11:36 AM, Joe Grames wrote:
> The folks responsible for steering the 2I/1I/0I region were either
> involved in defining the steering protocol or attending the training.
> At some level, Reza, Michele and I "owned" defining the protocol. It can
> certainly be a topic for discussion and changed.  Maybe we (I?) over
> simplified some steps in ~early 2010 in order to benefit the learning
> curves for a fairly significant process change, but many of the hooks
> are already in place to deal with setup steps.  It may be helpful to
> watch the training I gave to Ops - I am pretty sure Tom Oren videotaped
> one of the sessions.  I can also do this, and help collectively evolve
> the process.  In the end, human judgment is ~always required.
>
> On 4/19/2011 10:46 AM, Jay Benesch wrote:
>> Matt,
>>
>> I am saying that the reasons the scraping on A2 affects charge asymmetry
>> width were unknown to me, not that they are unknown to everyone.
>>
>> I hadn't looked at the injector steering screen enough to notice the
>> "saved orbit" option.  Perhaps it should be made the default instead of
>> "rels".
>>
>> If Ops can be trained to consistently autosteer the injector to the
>> saved orbit with A:C current ratio the same as that used to save the
>> orbit, I will be happy.  The steering script would have to provide the
>> ratio info in some manner on the screen which means that the person
>> saving the gold orbit would have to enter it in a new PV.
>>
>> [to all] Is getting the current ratio, say 10:16 A:C, sufficient? Or
>> does the injector steering need to be done at the full current of the
>> original setup to the inline dump, in which case target changes in the
>> halls will likely require that injector auto-steering always be done to
>> the inline dump.
>>
>> Jay
>>
>> On 4/19/2011 10:33, Matt Poelker wrote:
>>> And charge asymmetry is related to A2 interception because the beam
>>> moves left/right up/down because of helicity correlated beam motion
>>> originating at the pockels cell, something QWeak tries to minimize by
>>> doing their sensitive shifts-long pockels cell alignment.  Small
>>> scraping, smaller charge asymmetry, bifg scraping, bigger charge
>>> asymmetry.  Are you saying it behaves differently?
>>>
>>>
>>> Michele Joyce wrote:
>>>> FYI, the Injector Autosteer has a feature to use a "gold" orbit saved
>>>> by the Injector experts...as opposed to the relative orbit.
>>>> Michele
>>>>
>>>> On 4/19/2011 8:05 AM, Jay Benesch wrote:
>>>>> Assertions
>>>>>
>>>>> 1. with two high current halls the orbit is the weighted average of the
>>>>> beam centroids
>>>>>
>>>>> 2. Qweak charge asymmetry is related, for reasons unknown, to the amount
>>>>> of beam scraped off on A2
>>>>>
>>>>> 3. When Ops does a save with zero position it saves the relative orbit
>>>>> for all BPMs
>>>>>
>>>>> 4. Injector autosteer relies on the relative orbit
>>>>>
>>>>>
>>>>> Conjecture
>>>>>
>>>>> 0R04 trips may be related to the relative orbits of the A and C beams.
>>>>> http://opweb.acc.jlab.org/CSUEApps/elog02/elog_item.php?elog_id=1579572
>>>>>
>>>>>
>>>>> Suggestions
>>>>>
>>>>> "Zero position" option in SAVER should be modified from yes/no choice to
>>>>> three choices:
>>>>>
>>>>> a. zero position for injector "[0123]I", 0L, 0R
>>>>> b. zero position for everything else
>>>>> c. no ZP
>>>>>
>>>>> Ops could choose any one or the a/b pair.
>>>>>
>>>>> For restore, there could be a few more templates at the end under a BPM
>>>>> restore "menu": injector, machine, hall A, hall B, hall C.  Or people
>>>>> could simply be required to continue to grep the needed BPMs when
>>>>> restoring a relative orbit.
>>>>>
>>>>> Jay
>>>>>
>>>>> _______________________________________________
>>>>> Bteam mailing list
>>>>> Bteam at jlab.org
>>>>> https://mailman.jlab.org/mailman/listinfo/bteam
>>>>>
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