Hello Jeremy,

My list for magnet settings will be the following:
- beam energy (since magnet setting depends on it)
- analyzing magnet current as measure on power supply
- analyzing field as measured in the homogenous region
- frascati magnet current as measured on the power supply
- frascati magnet field value as measured in the homogenous region
Frascati setting is important since the beam direction on the target 
depends on it.
All of these will be injected to data stream as part of EPICS as well as 
will be
available through the slow control data base (MYA).

Of course, in addition to the field values in homogenous region we 
should have the full field
maps stored, available somewhere. We should define how we will scale 
field maps, e.g.
take the closest available (in current or in central field value) and 
scale, or fit point by point.

By the way, I am not sure what it means scaling factor, may be some one 
can explain me.

Regards, Stepan


On 2/2/15 8:55 PM, McCormick, Jeremy I. wrote:
> Hi, Norman.
>
> Thanks for the information.
>
> I basically need to know what the database table(s) should look like....
>
> e.g.
>
> What columns should it have?  What are the units on those columns?
>
> The proposal on the JIRA item currently is....
>
> field - the measured By (I think?) in Tesla, presumably of the analyzing dipole
>
> scale - scaling factor of the B-field for the run (all components)
>
> So is that enough for what we want to do with this information in recon/analysis?  Or do we need more columns with additional information?
>
> If we need more columns, please tell me what they should be.
>
> Also, if there are different conditions measured at different times (multiple magnets?), then we can model them with other classes.
>
> Right now, I'd propose a generic "BfieldConditions" object but we aren't limited to having one type if more classes/tables are needed for this.
>
> Thanks.
>
> --Jeremy
>
> -----Original Message-----
> From: Graf, Norman A.
> Sent: Monday, February 02, 2015 5:47 PM
> To: Nathan Baltzell; McCormick, Jeremy I.
> Cc: hps-software
> Subject: Re: Bfield conditions
>
> Jeremy, et al.,
>    We will need to monitor the analyzing dipole current. I assume this is an EPICS variable, or should be. We will also be mounting a Hall probe onto the SVT support plate. This will give us a direct measure of the magnetic field strength. Deviations from nominal settings will give us the scaling factor to use for the simulation/reconstruction. I would use the magnet current as the primary and the Hall probe as check, but we can monitor both during early commissioning.
> Norman
> ________________________________________
> From: [log in to unmask] <[log in to unmask]> on behalf of Nathan Baltzell <[log in to unmask]>
> Sent: Monday, February 2, 2015 5:24 PM
> To: McCormick, Jeremy I.
> Cc: hps-software
> Subject: Re: Bfield conditions
>
> Hi Jeremy,
>
>> current - the beam current in amps
> I think beam current is not related to chicane settings.
>
>> But I'm not sure where this information all comes from...
> Empirical numbers are magnet currents, from which comes a scale factor relative to some defined nominal value.
>
>> current - Will this be in the data stream for the upcoming runs?  Or
>> should we access it through the MYA command line tool?  (Obviously
>> prefer into the data stream.)
> We will be putting various EPICs variables, including chicane current readbacks, into EVIO every few seconds for the next run.  How we will parse it needs to be written and tested.
>
> -Nathan
>
>
>
> On Feb 2, 2015, at 7:44 PM, "McCormick, Jeremy I." <[log in to unmask]> wrote:
>
>> -----Original Message-----
>> From: McCormick, Jeremy I.
>> Sent: Monday, February 02, 2015 4:43 PM
>> To: 'Nathan Baltzell'
>> Cc: Graham, Mathew Thomas; Graf, Norman A.
>> Subject: RE: Bfield conditions
>>
>> Hi, Nathan.
>>
>> I'll CC a couple people who might be interested in this...
>>
>> It was requested that I add B-field information to the conditions system.
>>
>> https://jira.slac.stanford.edu/browse/HPSJAVA-312
>>
>> So I was planning to just add a single table with...
>>
>> current - the beam current in amps
>>
>> field - measured field value in tesla or kG
>>
>> scale - scaling factor of field map for the run
>>
>> But I'm not sure where this information all comes from...
>>
>> current - Will this be in the data stream for the upcoming runs?  Or
>> should we access it through the MYA command line tool?  (Obviously
>> prefer into the data stream.)
>>
>> field - Field value at the IP or some other position?  When is this measured?  How do we get it automatically?  Or do we just input this manually?
>>
>> scale -  I don't know how we get this number.  Is it derived from the current?  If it is derived should we even store it separately or just compute on the fly?
>>
>> I can add the API regardless of whether we know how to get the information, but we should discuss how to access/load this information up front.
>>
>> Thanks.
>>
>> --Jeremy
>>
>> -----Original Message-----
>> From: Nathan Baltzell [mailto:[log in to unmask]]
>> Sent: Monday, February 02, 2015 4:33 PM
>> To: McCormick, Jeremy I.
>> Subject: Re: Bfield conditions
>>
>> Chicane setting relative to nominal is in data catalog, done manually from the spreadsheet this time.  We also have magnet currents in epics.
>>
>> This will be something that will be in the jlab mysql run db next time (in progress ...).
>>
>>
>>
>> On Feb 2, 2015, at 7:23 PM, "McCormick, Jeremy I." <[log in to unmask]> wrote:
>>
>>> I might have missed this someplace....
>>>
>>> Do we have any B-field conditions for the runs?
>>>
>>> Like current, scaling, etc.
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