Re: Opinion on timing system for synchrotron beamlines

[bob dalesio <bob.dalesio@gmail.com>]

Local fly scans at NSLS II produce triggers at a high frequency or position based. In both cases, position at trigger is desired. Other parameters may also be triggered, time stamped and used for correlation at 1 ms resolution.

On Thu, Nov 10, 2016 at 8:32 AM, Timo Korhonen <Timo.Korhonen@esss.se> wrote:

Hi,

Some other useful accelerator events of interest could be things like
informing of an upcoming (top-up) injection.
These are usually less precisely timed than revolution clock (or a
subharmonic of it) but can be comfortably propagated over a timing (event)
system.

I have not seen a big interest from beam lines to use highly precise and
synchronised timestamps so far, although I can easily imagine cases where
that might be interesting. But I am not a beam line scientist so this is
just my imagination.
Most timing in the experiments happens anyway in a level where EPICS
cannot contribute much, so probably PTP level of accuracy is sufficient.


Timo



On 10/11/16 09:43, "tech-talk-bounces@aps.anl.gov on behalf of Alessandro
Drago" <tech-talk-bounces@aps.anl.gov on behalf of

Alessandro.Drago@lnf.infn.it> wrote:

>The same situation at DAFNE, we use fiducial (revolution ring clock) and
>injection trigger,
>
>Alessandro
>
>Il 2016-11-10 01:26 Mark Rivers ha scritto:
>> At the APS I would say that as far as I know no beamlines rely on
>> accurate timestamps from the accelerator timing system.   The
>> timestamps that the beamlines are using are based on NTP timing, so
>> are probably good to a few ms?
>>
>> What the beamlines do use are hardware timing signals that allow
>> experiments to synchronize to the ring electron bunch structure.
>> There is one signal that is a pulse at the ring frequency (orbital
>> period) and another that gives a pulse for each bunch in the ring.
>> These are used to synchronize lasers, fast shutters, fast detectors,
>> etc.
>>
>> Mark
>>
>>
>> -----Original Message-----
>> From: tech-talk-bounces@aps.anl.gov
>> [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Márcio Paduan
>> Donadio
>> Sent: Wednesday, November 09, 2016 1:27 PM
>> To: tech-talk@aps.anl.gov
>> Cc: Márcio Paduan Donadio
>> Subject: Opinion on timing system for synchrotron beamlines
>>
>>
>>      I'd like to know your experience regarding integration of the
>> accelerator timing system with the beamlines:
>>      - Which accelerator events are useful for the beamlines' control
>> system.
>>      - Do the beamlines use a global and very precise timestamp sent
>> from the accelerator timing system? What is the time precision?
>>      - Do you think that a PTP system is sufficient for timestamping
>> experiments in beamlines?
>>      - What is the EPICS role regarding such a timing system?
>>
>>      Thank you,