Date

Attendees

Discussion items

TimeItemWhoNotes     
30 minSXR Imager RequirementsAll

Parameter

Threshold

Objective

REXS

XPCS

CS

   

Pixel Pitch

50um

50um

✔

✔

✔

   

Read Noise

15e- rms

10e- rms

 

✔

✔

   

Quantum efficiency (250eV-1500eV)

70%

90%

✔

✔

✔

   

Frame Rate

5kHz

10kHz

✔

✔

✔

   

Array size

512 x 512

1024 x 1024

✔

 

 

   

Well Size (530eV photons)

1000

3000

 

 

✔

   

Vacuum compatibility

10-7T

10-9T

✔

 

 

   

Cabling and cooling length

2m

4m

✔

 

 

   

Physical package envelope

100x400x75mm

75x300x50mm

✔

 

 

   

Maximum Power dissipation

100W

50W

✔

✔

✔

         
30 minSparsification Strategy 

Goal here is to start a discussion on how and when it makes sense for to
sparsify (zero-suppress) data for LCLS science


From LDAC Report: '2018.R8) Quantitatively analyze the performance of the sparsification architectures,
and clarify its applicable range of scientific applications. In parallel, it is better to look at the technological
opportunities to make the frame rate higher, which will be applicable to all the potential applications.
Elaborate on the sparsification requirements, and assess the applicability to the foreseen scientific cases.' 

 

Our presentation to the LDAC outlined a High-Rate Development Framework:

•Advance the maximum read rates of the underlying ASICs, building blocks that drive and read out
the sensor arrays, consistent with the unique delivery format of the LCLS light source.
•Separately optimize sensor matrices and input stages to tailor response to specific LCLS science areas.
These building blocks combine with ASIC advances to provide high rates for all LCLS photon energies
(incl. LCLS-II-HE)
•Maintain existing pixel sizes to avoid compromising scientific areas that rely on high spatial resolution.
•Utilize sparsification for read rates beyond tens of kHz to achieve ~100kHz rates with manageable
impacts to facility computational resources.
•Continue to look for cost-effective solutions from all developers to fill technology gaps, mitigate
technical risk, and improve cost-effectiveness.
Task: Prepare a white paper with the quantitative analysis requested by the LDAC to support and define
a logical set of consideraions that yield a workable tradeoff between full-frame and sparsified readouits to
include at least:
  • Impact of high rates on data system and other facility support
  • On-chip vs. off-chip zero-suppression
  • Impact of occupancy on benefits of sparsification
  • Practical examples of sparsified detector readouts (Timepix 3/4, TID solutions, VIPIc, ??)

 

 

Action items