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What's a flagship experiment?
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Consensus
- MFX identity:
- high-throughput time-resolved multimodal imaging+spectroscopy for Biology and Chemistry.
- SPI belongs at CXI/TXI
- high rep rate enables:
- rapid crystallographic screening
- collection of larger datasets => better SNR
- increased temporal sampling
- high energy:
- Spectroscopy: Mo K-edge to study nitrogenases with LBNL
- Anomalous diffraction opportunities for phasing/anomalous difference density calculation.
- SFX: "As mentioned in a recent paper (https://journals.iucr.org/s/issues/2019/04/00/xh5054/index.html): crystals absorb less (may be less relevant to XFEL experiments), the Ewald sphere curvature is reduced (benefitting data completeness), and we can move the detector further away from the IP (making space for other devices and instruments)."
- high flux:
- EXAFS + (an example of signal poor experiment that could find a niche at MFX) on PSII
Sticking points
- "specialization vs flexibility": specialization is key?
- "not-low" background at MFX means:
- SPI belongs at CXI/TXI? EXAFS could find a niche at MFX to rival recent developments in synchrotrons?
- we can get a clean signal when performing the experiment in a helium environment. Have there been any systematic studies of the data quality collected on the sample in vacuum vs helium? Are all sample delivery methods compatible with a helium environment (MESH, electrospray)? What do we know about helium availability and price in the future?
- higher flux: "will this be an increase in the overall photons per second, or will we also have an increase in intensity per pulse? In case of the latter, we will not see an increase in signal."
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- High repetition rate: this will this be useful for rapid crystallographic screening, but I am also very excited about increasing the temporal sampling within a single experiment. In time-resolved crystallography, we often collect only a few timepoints and have to deal with a mixture of active state intermediates. Better temporal sampling will allow us to see the increase and decrease in occupancy of these active state intermediates and may allow us to better deconvolute intermediates in the electron density.
- Higher repetition rates will allow us to collect larger datasets and push the SNR. This is very important for ultrafast experiments, in which the occupancy of the active state is very limited (due to e.g. short pulse duration of the femtosecond pump laser).
- Regarding CXI vs MFX, we can get a clean signal when performing the experiment in a helium environment. Have there been any systematic studies of the data quality collected on the sample in vacuum vs helium? Are all sample delivery methods compatible with a helium environment (MESH, electrospray)? What do we know about helium availability and price in the future?
- Regarding the increase in flux: will this be an increase in the overall photons per second, or will we also have an increase in intensity per pulse? In case of the latter, we will not see an increase in signal.- Regarding the K-edge and X-ray spectroscopy: X-ray absorption is not just great for spectroscopy, it can be very informative in diffraction experiments as well. Absorption allows us to calculate anomalous difference density maps using MR-SAD, to localize the ion in the electron density and calculate its occupancy.
- An increase in X-ray energy is something that is also being explored at synchrotrons. As mentioned in a recent paper (https://journals.iucr.org/s/issues/2019/04/00/xh5054/index.html): crystals absorb less (may be less relevant to XFEL experiments), the Ewald sphere curvature is reduced (benefitting data completeness), and we can move the detector further away from the IP (making space for other devices and instruments).
- I am excited about the multimodal scattering-spectroscopy beamline idea. XRD+XES was also one of the highlights of the conference I recently attended, many scientists in the bio community are very eager to complement their time-resolved diffraction experiments.
Notes from July 13 meeting
(I'm still in the process of compiling... below is rough draft)
Sandra - points out confusion about MFX 2.0, MFX HE, BRaVE, etc.
Sandra - Does MFX HE aim for something like BRaVE or something fancier (attosecond, etc...) more flexible
Dan - Build a stable setup that enables high-throughput through automation, but leave the possibility initially to pull it out so time can be devoted to cutting-edge user experiment: balance stable with flexible initially. Eventually, integrate R&D in stable setup which will prevail over time.
Automation creds at Dan's previous beamline: video of a robot taking a sample from a 96 will plate, moving it to the IP, triggering data collection and analysis, stop when complete, wash and repeat.
Limiting factors of high-throughput:
- Detector readout rate
- expect 25 kHz?
- Sample volume
- Sample delivery rates:
- DoD at 5-10 kHz
- DoT: hurdles with sticking on tape.
- liquid jets (demo at FLASH: GDVN at 4.5 MHz).
- high viscosity extrusion at high rep rate: need analysis to show feasibility
Ray - Yavas work assignment: MFX-HE will see the first HE light: high profile!
Ray - New KB: smaller focus for nano-crystallography would make MFX more appealing to traditionally CXI folks like Weik and Colletier
Ray - Pulse picker: which science cases would need it? Fixed target with ultrafast scanning needs PP.
Dan - Goal: zero/one operator system ==> complicated tape systems that require huge team would not fly. Liquid handling stuff is easier.
Ray - Nice-to-have: option to use tapes for world-class science
Tension between automation and world-leading science case:
- Automation should free us so we can focus on more complex science cases
- Automation means leaner budget
- Automation means standardization which results in guarantees - something appealing to a wider audience, in particular industry
Dan's experience with automation: 4 years to build, last year they (Genentech) came.
Industry needs:
- Todo: figure out the industry needs: Genentech, Insitro, Gilead, Altos, Amgen, etc...
- They need a risk profile: what can they get if they pay for private beamtime; can they publish if they go for public beamtime
- Ray's point about LCP and DMSO mixing issue (Viscosity challenge): impossible at synchrotrons, possible at XFEL, but viscosity is a major hurdle for high-throughput
Timeline: what's feasible in 1/3/5 years in terms of HTP system.
Our strong suite:
- room temperature
- radiation damage free
- time-resolved
- + spectroscopy
How does that define us versus competition with synchrotrons and cryoEM?
How many structures a day? (revisit this thoroughly)
- conservative: 1/hour
- optimistic: 1/2min
- sample volume challenge.
- appeal for molecular movies, salt screening, etc.
- performance metric that we can guarantee to attract users.
- fXS: similar metric?
Flagship: in 3 years, state of cryoEM - what's left for XFELs?
One-stop-shop for Bio strategy? Couple MFX with other capabilities? ...
Document: there is a useful untapped science in solving static structures. Make that statement emerge from need sourcing.
Possible renaissance in comp.meth.dvlpmt for crystallography and ML: more info extracted from the same data. Opportunity for HTP
Flagship is the technique:
- Goal #1 "Le Mans": from collection to structure in 1hour, tirelessly for 24 hours with 1 operator
- Goal #2: from that baseline, go to time-domain: automatic sampling of reaction coordinates.
TODO:
- Calculation: what can be delivered - reach out to experts
- Figure out industry needs