Re: [BLAST_SHIFTS] Shift summary 04/15/2005 C (17-1)

From: Akihisa Shinozaki (shino@lns.mit.edu)
Date: Sat Apr 16 2005 - 17:00:12 EDT


Hello,

I will run the Tylan's script from run 15313. I am currently power
cycling the HV crate and the script is running ok.

Thank you,
aki

Taylan Akdogan wrote:

> Hi,
>
>
> This is fine until we have the ABS software. As Michael noted;
> for the false asymmetry extraction, we prefer to have -exactly-
> the same operating conditions.
>
> I have two remarks about the script:
>
> 1) Although, you set the target state to 0 while changing the
> bits, this will have no effect in practice. CA (epics
> channel access) library is a highly optimized - good design -,
> and it will most likely deliver the commands in the right order
> but at the same time (same epics update interval) to the
> ABS.STATUS channel. Thus, the change in status will be done
> instantly on all bits for all practical purposes, without
> any status-0 target.
>
> To mimic the ABS operation (I assume this should be the aim),
> put a delay after setting the status bit to 0. Is is something
> like 5 sec? (attached the changed script)
>
> 2) Isn't the ABS transition sequence quasi-random? If so,
> same algorithm is desirable for this script, rather than
> linear change sequence.
>
> Taylan
>
>
>
> On Apr 16, 2005, at 3:57 PM, Akihisa Shinozaki wrote:
>
>> Hello there,
>>
>> I made a simple shell script to flip the spin bits. I have not run
>> the script on one of the dblast machines because I do not want to
>> screw things up. It flips the bits every 10 minutes. Every 10
>> minutes, the script flips from state 1,6> to 2,5> or 2,5> to 3,4> or
>> 4,5> to 1,6>. During the flip, the target status bit (6) is set to
>> 0. I think I need someones approval before I run this thing. What
>> do you think?
>>
>> Thank you so much,
>> aki
>>
>> Taylan Akdogan wrote:
>>
>>
>>>
>>> On Sat, 16 Apr 2005, Michael Kohl wrote:
>>>
>>>
>>>>> - Had to change the ABS states manually, because ABS software
>>>>> was not running.
>>>>>
>>>>>
>>>>>
>>>> Just as a comment,
>>>>
>>>> if we want any confidence on false asymmetries measured with the
>>>> unpolarized system, we need to run the experiment in the same way
>>>> like with the ABS, i.e. with the ABS software (even if the ABS
>>>> software only uses the commands to set the spin bits that Taylan
>>>> invoked manually).
>>>>
>>>> Otherwise, the unpolarized running is only good for the luminosity
>>>> check.
>>>>
>>>> Regards,
>>>>
>>>> Michael
>>>>
>>>>
>>>
>>>
>>> I agree. I should have been more informative about this in the
>>> shift summary: Because of the SFT problem, Genya didn't want to
>>> turn on ABS RF, so didn't want to run the ABS software. (elog 34974)
>>>
>>> I'm sure, we can/will use the ABS software for future unpol runs
>>> as was used in the past, once it's fixed.
>>>
>>> Taylan
>>>
>>> --
>>> ---=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=---
>>> Taylan Akdogan Massachusetts Institute of Technology
>>> akdogan@mit.edu Department of Physics
>>> Tel: +1 (617) 258-0801 Laboratory for Nuclear Science
>>> Fax: +1 (617) 258-5440 Room 26-559
>>> ---=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=---
>>>
>>>
>>>
>>> <test.sh>
>>
>>
>



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