Shutter Open/Close Speed at XPD

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gerard...@stonybrook.edu

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Nov 7, 2018, 6:10:29 AM11/7/18
to xpd-users
Just some thoughts/questions on high-throughput data collection at XPD:

The Tseries scan plan has a parameter for controlling the delay time between
subsequent data acquisitions at XPD. For our time-resolved experiments,
it's sometimes useful to keep the delay time between scans very short (~0.5 sec or less), to 
maximize the number of data points acquired, assuming there are no other experimental
issues (detector saturation, etc). 

We've had experiences at other user facilities where our limiting factor during
data acquisition ends up being the physical speed at which the fast shutter is able to fully open/close
before the start of the next scan. This has led to some issues where the delay
time isn't long enough, resulting in data being acquired with a half open/closed shutter. 

Is there a general rule of thumb at XPD for the maximum data acquisition rate
(Ex: 2 scans / sec, 1 scan / sec, etc) to employ that will still give the fast shutter 
a long enough window to close properly?  

Ghose, Sanjit

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Nov 7, 2018, 8:38:53 AM11/7/18
to gerard...@stonybrook.edu, xpd-users

As of now, 1 sec minimum delay is required for shutter open/close between frames in tseries. If you want faster run tseries is open mode between frames if does not affect your consecutive data.

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Chia-Hao Liu

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Nov 7, 2018, 12:14:35 PM11/7/18
to xpd-users
Thanks, Sanjit. Just to fill in more details here:

As for collection rate, the highest frame rate for the area detector at XPD is ~10 frames/s.
By default, the shutter will remain closed between scans to protect detector in our Tramp and tseries scans. 
As Sanjit mentioned, it takes about 1 sec to open and close the fast shutter. Therefore with the default behavior, the best acquisition rate is ~1 frame/sec (from open/close shutter)
User can also override the default behavior on shutter control, so that shutter is always open during data collection and the best acquisition rate is now ~5 frames/sec (from the detector plus normally 0.1s overhead in software)
The 0.1s software overhead is reported by beamline. The detailed discussion is here: https://github.com/xpdAcq/mission-control/issues/120

The syntax of overriding the default behavior (and other information about the ScanPlan) could be found in our online doc:

Hope that hopes,
Tim
On Wednesday, November 7, 2018 at 8:38:53 AM UTC-5, Ghose, Sanjit wrote:

As of now, 1 sec minimum delay is required for shutter open/close between frames in tseries. If you want faster run tseries is open mode between frames if does not affect your consecutive data.

 

From: <xpd-...@googlegroups.com> on behalf of Gerard Mattei <gerard...@stonybrook.edu>
Date: Wednesday, November 7, 2018 at 6:10 AM
To: xpd-users <xpd-...@googlegroups.com>
Subject: [xpd-users] Shutter Open/Close Speed at XPD

 

Just some thoughts/questions on high-throughput data collection at XPD:

 

The Tseries scan plan has a parameter for controlling the delay time between

subsequent data acquisitions at XPD. For our time-resolved experiments,

it's sometimes useful to keep the delay time between scans very short (~0.5 sec or less), to 

maximize the number of data points acquired, assuming there are no other experimental

issues (detector saturation, etc). 

 

We've had experiences at other user facilities where our limiting factor during

data acquisition ends up being the physical speed at which the fast shutter is able to fully open/close

before the start of the next scan. This has led to some issues where the delay

time isn't long enough, resulting in data being acquired with a half open/closed shutter. 

 

Is there a general rule of thumb at XPD for the maximum data acquisition rate

(Ex: 2 scans / sec, 1 scan / sec, etc) to employ that will still give the fast shutter 

a long enough window to close properly?  

 

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