DanMAX — Beamline components

Reference inventory of the physical hardware that makes up the DanMAX beamline at MAX IV, walked from the source to the detectors. Primary source for the values below is the DanMAX Detailed Design Report v2.0 (December 2017, by I. Kantor and E. Bergbäck Knudsen, DTU, with M. R. V. Jørgensen, Aarhus University); the public beamline page at maxiv.lu.se/beamlines-accelerators/beamlines/danmax/beamline-optics/ is the fallback for items the DDR doesn’t cover.

Note

DanMAX is operational since 2019–2020. Values below come from the design report and may differ from the as-built / current commissioned state. The control system is TANGO + Sardana (motor electronics: ESRF IcePAP), not EPICS, so PV-style addresses on this page are placeholders; the operational surface is Sardana/TANGO attributes.

Overview

DanMAX sits at achromat 4 of the MAX IV 3 GeV ring, dedicated to in situ / operando materials studies in the 15–35 keV range. Two end-stations live in a single shared experimental hutch (EH1): an imaging instrument (full-field absorption / phase contrast / grating-based) and PXRD instruments (high- resolution powder diffraction + large-sample-environment 2D diffraction). A future second experimental hutch (EH2) is reserved between the optics hutch and EH1.

Walk from source to detector (z values from the centre of the storage straight section, mm, per DDR Table 3):

IVU16 (in-vacuum undulator)            (3.0 m magnetic length, achromat 4)
  -> Front End (Toyama)                (FE Aperture at z ≈ 19.2 m)
  -> Ratchet wall                      (z = 21.8 m)
  -> Optics hutch (OH, 9.9 m long)
       Trigger unit                    (z = 22.75 m)
       Bremsstrahlung collimator       (z = 23.17 m)
       High-pass filter (diamond)      (z = 23.52 m)
       Laue monochromator (placeholder) (z = 23.89 m)
       White beam slit 1               (z = 24.46 m)
       BV1 (diagnostics)               (z = 24.91 m)
       hDCM (Si 111, horizontal)       (z = 25.655 m)
       BV2                             (z = 26.40 m)
       hMLM (multilayer, horizontal)   (z = 27.27 m)
       White beam stop + bremss. coll. (z = 28.19 m)
       Monochromatic slit 1            (z = 28.44 m)
       BV3 + future BPM                (z = 30.55 m)
       CRL transfocator (Be lenses)    (z = 31.10 m)
       Monochromatic slit 2            (z = 31.60 m)
       Safety shutter                  (z = 32.20 m)
       OH end wall                     (z = 32.50 m)
  -> Experimental hutch EH1            (upstream wall ≈ 38.1 m)
       Imaging instrument              (sample at z ≈ 41.2 m)
       High-res PXRD instrument        (sample at z ≈ 44.8 m)
       Large-sample-env PXRD instrument (sample at z ≈ 48.2 m)
       Far-field detector positions    (8–10 m downstream of sample)

Beam delivery

Insertion device — IVU16

Role:

Primary photon source. Optimised for maximum flux at the high-energy end (~35 keV); spectroscopy-style spectral purity is not a design driver.

Family:

InsertionDevice

Type:

In-vacuum permanent-magnet undulator (room temperature)

Vendor:

Hitachi (contract July 2016; delivery January 2018)

Magnet pole material:

NdFeB

Pole material:

Vanadium Permendur

Period length:

16 mm

Number of periods:

187

Magnetic length:

~3.0 m

Magnetic gap range:

4.0 – 50.0 mm

Minimum physical gap:

3.8 mm

Peak field at min. gap:

1.181 T

Effective field at min. gap:

1.114 T

Effective K at min. gap:

1.66

Photon energy range:

9.5 – 40 keV (operational use 15 – 35 keV)

Electron beam size (RMS):

53.9 µm × 6.3 µm (h × v)

Source size (RMS):

53.9 µm × 6.4 µm (h × v)

Source divergence (RMS):

11.3 µrad × 9.8 µrad (h × v)

Power at 4 mm gap:

~11 kW (total emitted)

Front End

Role:

Mask + diagnostic stack that defines the maximum acceptance of the beamline and protects downstream optics.

Family:

BeamMask + Diagnostics

Vendor:

Toyama (essentially an upgraded version of the MAX IV phase-1 front ends)

Layout:

  • Fixed mask 1: 1 × 1 mrad² aperture, absorbs ~70 W (wide opening to allow XBPM functionality).

  • XBPM1 and XBPM2 — two beam position monitors separated by ~3 m (z = 12.0 m and z = 15.1 m), feed an orbit correction loop.

  • Fixed mask 2: 100 × 100 µrad² aperture, absorbs up to 9.5 kW (z ≈ 16 m). Defines the maximum opening.

  • Movable masks downstream of FM2 — restrict acceptance to 35 × 35 µrad² in normal operation, transmitting at most ~125 W. PLC-interlocked: the mask opening cannot exceed 35 × 35 µrad² if the undulator gap is closed and storage-ring current is high.

FE Aperture position:

z ≈ 19.2 m

Ratchet wall:

z = 21.8 m (boundary into the optics hutch)

Optics hutch (z = 22.5–32.5 m)

All optical elements with their longitudinal positions (DDR Table 3) — distance from the centre of the IVU16 straight:

Component

Length (mm)

Centre z (mm)

IVU16 (source)

3700

0

XBPM 1

—

12000

XBPM 2

—

15100

FE Aperture

—

19200

Ratchet Wall

1400

21800

Trigger Unit

500

22750

Bremsstrahlung collimator

200

23170

Diamond filter (high-pass)

200

23520

Laue Monochromator (placeholder)

400

23890

White beam slit 1

300

24460

BV1

300

24910

hDCM (Si 111)

750

25655

BV2

300

26400

hMLM (multilayer)

1000

27270

White beam stop + bremss. collimator

400

28190

Monochromatic slit 1

100

28440

BV3 + future BPM

500

30550

CRL transfocator

600

31100

Monochromatic slit 2

100

31600

Safety shutter

400

32200

OH end wall

200

32500

High-pass diamond filter

Role:

Absorbs the low-energy fundamental harmonic (~2.2 keV) from the IVU16, dropping the heat load on every downstream optical element.

Family:

Filter

Material:

Single-crystal diamond, total thickness 1.0 mm (stacked plates)

Position:

23.52 m from source

Power absorbed:

~75 W (transmits ~55 W at peak)

Transmission:

~75 % at 15 keV, 92 % at 35 keV

hDCM — Horizontally-deflecting Double-Crystal Monochromator

Role:

High-resolution monochromatic mode (ΔE/E ~ 10⁻⁴). Provides the cleanest beam for spectroscopy-grade imaging and diffraction.

Family:

Monochromator

Geometry:

Horizontally deflecting (consistent with BioMAX, NanoMAX, CoSAXS) — chosen for mechanical rigidity (no gravity on the rotation axis) and freedom from vertical-divergence broadening.

Crystals:

Si (111), two-bounce, fixed exit

Cooling:

Liquid nitrogen on both crystals (Si negative-thermal- expansion regime; produces a slight horizontal thermal-focus bump)

Energy range:

15 – 35 keV

Energy resolution (ΔE/E, FWHM):

1.7 × 10⁻⁴ @ 15 keV to 3.2 × 10⁻⁴ @ 35 keV (< 1 × 10⁻⁴ ΔE/E RMS in design)

Horizontal offset (fixed-exit mode):

10 mm (DCM alone), 4 mm (when combined with the MLM downstream)

Position:

25.655 m from source

Power on first crystal:

71 W (peak power density < 20 W/mm²)

Beam divergence (after hDCM):

meridional 5–6 µrad RMS, sagittal 3–4 µrad RMS

hMLM — Horizontally-deflecting Multilayer Monochromator

Role:

High-intensity quasi-monochromatic mode (ΔE/E ~ 0.3–1 %). Optimal for fast absorption-contrast imaging and fast diffraction; also used downstream of the hDCM for harmonic rejection at low energies (15–20 keV).

Family:

Monochromator

Geometry:

Horizontally deflecting, two-bounce, fixed exit (10 mm offset alone; 6 mm offset when combined with hDCM)

Multilayer coatings:

Two adjacent coatings on a single Si substrate per mirror:

  • B₄C / W, 25 Å period, Γ = 0.8, 200 bilayers (ΔE/E ~ 1 % bandwidth — main high-intensity coating)

  • B₄C / Ni₀.₉₅V₀.₀₆ (Ni–V alloy), 20 Å period, Γ = 0.65 (ΔE/E ~ 3.5 × 10⁻³ — intermediate-bandwidth option)

Substrate roughness:

< 3 Å RMS (interface) / ~1 Å RMS (substrate)

Incident-angle range:

0.41° – 0.97°

Cooling:

1st mirror water-cooled; 2nd mirror copper-braided or solid-Cu thermal link into cooled EGaIn bath

Power absorbed (MLM-only mode):

~65 W on 1st mirror (~2.5 W/mm²)

Position:

27.27 m from source

Operating modes (DDR §4):

  • hDCM only — high-resolution monochromatic, no harmonic rejection; PXRD and phase-contrast imaging in the cleanest band.

  • hDCM + hMLM — high-resolution mono with harmonic rejection (necessary at 15–20 keV where harmonic contamination is significant, λ₃/λ₁ ~ 5 × 10⁻⁴ from hDCM alone).

  • hMLM only — quasi-monochromatic, maximum flux. Best for fast absorption-contrast imaging and fast (low-resolution) diffraction.

CRL transfocator

Role:

First focusing element of the beamline. Be CRL pack delivers a stable, convenient spot-size variation at the sample.

Family:

CRL (compound refractive lens transfocator)

Position:

31.1 m from source (in the optics hutch)

Lens material:

Beryllium

Lens count:

50, grouped into 6 selectable sub-groups

Adjustable spot size at sample:

~40 × 10 µm² to 1.3 × 1.2 mm² (FWHM, with hDCM); ~10 × 100 µm² to 1.2 × 1.3 mm² (with MLM)

Beam divergence at sample (focused / collimated):

  • hDCM collimated: ~1.5 × 1 µrad² RMS (h × v)

  • hMLM collimated: ~5 × 0.5 µrad² RMS (h × v)

Diagnostics (BV1, BV2, BV3)

Role:

Retractable beam viewers after each major optical element. Single physical design used at all three positions.

Family:

Diagnostics

Mechanism:

Diamond foil screen — Compton-scattering intensity → in-vacuum diode, fluorescence → optical microscope + GigE digital camera.

Insertion:

Pneumatic actuator (retractable; in operation at the cost of lower transmission downstream).

Positions:

BV1 at 24.91 m, BV2 at 26.40 m, BV3 at 30.55 m.

Radiation safety

Role:

Bremsstrahlung collimators + white-beam stops + safety shutter at the downstream end of the optics hutch protect EH1 and personnel.

Family:

Shutter / Stop

Layout:

  • Bremsstrahlung collimator at OH entrance (z = 23.17 m)

  • White-beam stop + bremsstrahlung collimator downstream of hMLM (z = 28.19 m)

  • Optional 3rd bremsstrahlung collimator upstream of photon shutter (TBD per DDR §7.7)

  • Photon (safety) shutter at z = 32.20 m

Experimental stations (EH1)

EH1 is a 13.8 m × 4.5 m hutch hosting three sample positions in series along the beam. A common kinematic detector mount lets (nearly) all detectors at DanMAX be used on any instrument.

Imaging instrument

Role:

Full-field imaging (absorption / phase / grating contrast) for in situ / operando studies of bulk materials and objects. Designed for 50 nm – 5 µm spatial resolution and time-resolved 3D acquisitions.

Family:

Imaging endstation

Sample position:

z ≈ 41.2 m from source

Sample stage:

Precise tomographic rotation stage on an air bearing, mounted on a granite support (which also carries the near-field detector and the EH-side focusing optics).

Near-field detector:

directly downstream of the sample, on the granite block (removable / movable inboard-outboard to clear the beam to the PXRD instruments).

Far-field detectors:

e.g. for diffraction-contrast imaging, can be positioned anywhere from 8 to 10 m downstream of the sample for grazing scattering-angle work, or at the far end of the hutch for ptychography.

Beam shaping:

A vacuum window + beam monitor at the EH1 upstream wall (z ≈ 38.1 m), followed by an in-hutch focusing device or devices that tightly focus the beam at z ≈ 41.2 m.

High-resolution PXRD instrument

Role:

Medium-to-high resolution powder X-ray diffraction with a sample-changer robot for high-throughput.

Family:

PXRD endstation

Sample position:

z ≈ 44.8 m from source

Diffractometer:

Two-circle

Detector:

1D strip detector, Dectris Mythen 24K (or similar)

Sample handling:

Robot sample changer

Sample environments:

Height-adjustable table in front of the goniometer for small-to-medium sample environments.

Large-sample-environment PXRD instrument

Role:

PXRD for heavy / large sample environments (e.g. magnets, pressure cells, gas rigs).

Family:

PXRD endstation

Sample position:

z ≈ 48.2 m from source

Sample stage:

Hexapod, carrying up to ~250 kg

Detector:

2D area detector, Dectris Pilatus 3X CdTe 2M (or similar). Movable on a highly flexible XYZ mount, with adjustable 2θ.

Additional detectors:

Energy-dispersive detector option (for fluorescence signal); motorised beam stops with beam-imaging / intensity-recording capability.

Detector-share:

The 2D area detector mount is shared with the far-field imaging detector — same kinematic interface regardless of which instrument is in use.

Sample environments and gas system

EH1 carries a permanent gas system (similar to the one at BALDER) plus process ventilation with fume-extraction arms and gas sensors for in situ gas / chemistry experiments. A sample-environment (SE) preparation area sits adjacent to the control room.

Control system

DanMAX runs the standard MAX IV control stack — not EPICS:

Backbone:

TANGO (process bus)

User interface / sequencer:

Sardana

Motor electronics:

ESRF IcePAP

The user-facing control interfaces are Sardana macros + GUIs on top of TANGO. The MAX IV Control & IT group provides the core hardware-to-network plumbing; advanced data-collection and sample- environment-integration layers are developed by the DanMAX team.

For the on-going APS ↔ DanMAX collaboration on the tomography scan engine — mapping the existing APS 2-BM tomoscan onto DanMAX’s Sardana-based equivalent — see DanMAX TomoScan — APS collaboration.

References