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Welcome to PROXIMA-2A! 
A leading light for biology and micro-crystallography.

PROXIMA 2A (PX2-A) is a microfocus beamline dedicated to biological crystallography and innovative micro-beam methodologies. Opened to the scientific community since 2013, the topics treated on the beamline go beyond standard protein crystallography and include drug discovery, membrane proteins, virus crystallography, small molecule crystallography, powder diffraction and even crystalluria.   The beamline is highly automated and designed to help scientists tackle the most challenging structural targets and biological systems. The X-ray energy is rapidly tunable over a wide range (6-18 keV) making the most commonly used absorption edges accessible for anomalous diffraction experiments.  The end station is equipped with a high capacity sample-changing system (148 SPINE pins), a high performance micro-diffractometer with a mini-kappa (MD2), an X-ray fluorescence detector (KETEK), and a fast, low-noise, photon-counting, area detector - the EIGER X 9M (238 fps in 9M mode, 750 fps in 4M mode).

See also Biology Health : HelioBio


Beamline Manager
SAVKO Martin
Beamline Scientist
Beamline Scientist
PERL David
Assistant Engineer
Beamline Scientist
Doctoral Student

Job Opportunities

Please contact William SHEPARD for more information.

Posters & Presentations

Poster - "The CRIBLEUR: An Any Format Screener for in situ X-ray Diffraction Experiments on PROXIMA 2A"

  • Biologie Structurale Integrative (BSI), 29 Nov - 03 Dec 2021, Paris-Saclay, France.

Webinar - "Of Symmetry, Lattices & Space Groups"

  • ReNaFoBis Webinar Series, 09 Dec 2020, Paris, France

Technical data

Energy range

6 - 18 keV

Energy Resolution

~0.0002 (Si 111)


Two U24 canted undulators (4.5 mrad)

Flux @ first optical element

White beam – depends on undulator settings


Cryogenically cooled channel cut crystal monochromator, a convex prefocussing mirror and a Kirkpatrick-Baez pair of focussing mirrors




EIGER X 9M area detector for X-ray diffraction images (238 fps in 9M mode, 750 fps in 4M mode)

Ketek SDD detector for X-ray fluorescence scans

Diamond scCVD and Ti foil XBPMs

High resolution X-ray camera (SOLEIL in-house design)

Scientific opportunities


Small and weakly diffracting crystals

SAD and MAD phasing

Phasing with a range of heavy atoms, including sulphur

Plate screening

Screening of crystallization trays


PX2-A Scheduling Calendar

Calendars of the available beamtime on the PROXIMA 2A beamline are available at these links:


Before visiting PX2-A

Please contact your LC before departing your lab or starting your session if collecting via remote access.

Sending Dewars

For REMOTE ACCESS users, please also send with your Dewar:

  • a Hard Disk Drive (HDD 1-2 To)
  • a Return Label or Return Way Bill

Dewars should be sent to your Local Contact (one of the people below):

  • William SHEPARD (Beamline Responsable)
  • Serena SIRGU
  • Martin SAVKO

PROXIMA 2A beamline telephone numbers (use on of these for transporting Dewars):

  • +33-1-6935-8180 (fixed land line)
  • +33-1-6935-8181 (hand held wireless)


SOLEIL's address is:

Synchrotron SOLEIL
L'Orme des Merisiers
Saint-Aubin, BP 48

Please notify your Local Contact, so that (s)he can refill your dewar upon arrival!

The return of shipping dewars shall be paid by the user. Please provide a FEDEX or DHL account number to your Local Contact. Click here to download a copy of the Dewar Return Form.

Remote Access


  • Please read the documentation to connection via NoMachine (NX)
  • Ensure that you have:
    • a high resolution screen (2560 * 1440 pixels) - this is VERY IMPORTANT
    • a 3-button mouse with a scroll wheel (for centering crystals)
    • an ADSL or fiber-optic internet connection
  • Test your Remote Access connection
    • organise a time to test with the PX2-A staff
    • test the connection 2-3 days before your session
  • Dewars
    • Label your Dewar properly
      • Your name, address & email
      • Project Number
      • Beamline
      • Local Contact or BL Manager
    • Include the following with your Dewar
      • a Hard Disk Drive (HDD 1-2 TB)
      • a Return Shipping Label or Transporter Account Number
    • Send or drop off your Dewar, which must arrive:
      • either 24 hours before your session
      • or the Friday morning for weekend sessions
      • Dewars may be dropped off at the SOLEIL gate

    Types of samples (and videos)

    PROXIMA-2A will take ANY & ALL samples! This includes the BIG, the SMALL and the UGLY!

    • big > 10 microns
    • small < 10 microns
    • ugly = split, fractured and clumped crystals, because these are sometimes made up of nice micro-crystals!

    Types of sample pins :

    - SPINE standard pins only

    • pin length = 22 mm (from loop to base)
    • goniometer horizontal range = -25 to +5 mm

    - Manual mounting

    • Suitable pins are Hampton, Mitegen & Molecular Dimensions
    • Goniometer now contains a mini-kappa, which can incline the smart magnet for easy cryo-transfers (set omega = 0° and kappa = 30 - 60°)

    - Robot mounting

    • The CATS robotic sample changer can hold up to nine (9) uni-pucks which each hold 16 SPINE pins, for a total of 144 pins
    • Suitable pins are Hampton, Mitegen & Molecular Dimensions

    A short video explaining mounting procedures :

    A further video showing the use of a dry shipper and sample recovery :

    During your visit

    - Start & finish times for PROXIMA-2A users:

    • 8:30 am – 8:00 am

    - Equipment & accessories available to users include:

    • Microscopes, SPINE pins, loops & wands for fishing crystals
    • Cryo-equipment - liquid nitrogen, handling dewars, cryo-tongs, gloves, etc...

    - Data Collection Control: Users launch their experiments via the MXCuBE GUI. See the link below for the PX2-A MXCuBE users guide:

    - Functionalities

    • beam location
    • sample transfers (manual & robotic)
    • crystal centring
    • data collections
    • energy changes, Escans & XFE spectra
    • Mesh, Grid and X-ray centering scans

    - Accessible X-ray wavelengths

    • 6 – 18 keV

    - Accessible absorption edges

    • K-edges Cr – Zr
    • L3-edges Ce - U

    - Typical data collection times

    • Minimum exposure time 4.2 ms per frame (238 fps), nominal exposure time 4.5 ms per frame (222 fps)
    • 16.2 s per nominal data collection rate (4.5 ms per frame, 0.1 degrees per frame, 3600 frames)
    • most crystals require 4.5 ms per 0.1 degrees oscillation angle

    - Visualising diffraction images

    • ALBULA
    • ADXV

    - Data processing

    • XDSME

    - Canteen Opening Hours

    • Closed during shutdowns
    • Weekdays (Monday - Friday) : Breakfast 7:30 - 9:00   Lunch 11:45 - 13:45      Dinner 19:00 - 21:00 (closing at 21:30)
    • Weekends& Holidays :             Breakfast 7:30 - 9:00   Lunch 12:30 - 13:30      Dinner 19:00 - 21:00 (closing at 21:30)

    After your experiment

    - Recuperating your data

    • download on to external disk drives via USB2 port
    • if possible, use the automated script "altsync" (Cntrl-C to stop, and then dimount the drive).
    • Only low volumes of data (e.g. MTZ files) can be practically downloaded via the SOLEIL Data Retrieval system


    - Remove ALL of your samples

    - Sign the Safety Approval Sheet

    Important: Please send to us any slides, images or publications of your results... the more the merrier! Bon courage!