Specimen Holders for X-Ray Diffraction (XRD): Types, Design, and Custom Solutions
XRD Knowledge Base · 2026 Edition
Specimen Holders for X-Ray Diffraction (XRD): Types, Materials & Custom Solutions
A practical, instrument-aware guide to standard powder holders, zero-background holders, low-background quartz, and custom geometries — with selection rules, materials trade-offs, and OEM compatibility for Rigaku, Panalytical (Malvern) and Bruker diffractometers.
6
Holder Types
3
Material Classes
60+
Stock SKUs
100%
Custom-Ready
X-ray diffraction is only as accurate as the position of the sample. Even a flagship diffractometer cannot recover from a holder that lifts the powder above the focusing circle, contributes a parasitic peak, or fluoresces under Cu Kα radiation. The specimen holder — the small machined plate or cup that secures your sample at the goniometer’s measurement plane — is the single component most often blamed for “phantom” peaks, intensity drift, and disagreement with reference patterns.
This guide is written for materials scientists, pharma analysts, and OEM service engineers who specify XRD holders. It covers the six functional categories you will actually buy, the materials trade-off between fused quartz, single-crystal silicon, optical glass, and PMMA, and the design tolerances that determine whether your holder works on a Rigaku Smartlab, a Malvern Panalytical Empyrean, or a Bruker D8 Advance. Where competitor articles stop at descriptions, this one gives you the numbers and selection rules you need to order with confidence.
Why this guide is reliable. MachinedQuartz manufactures more than 60 stock specimen-holder SKUs and ships custom designs to materials-research labs and instrument OEMs worldwide. The geometry, depth, and material recommendations below come from production drawings cross-checked against published references, not generic content scraped from competitor sites.
1. What an XRD specimen holder actually does
An XRD specimen holder performs three jobs simultaneously, and a good design has to balance all three:
- Position the sample at the focusing circle. In Bragg-Brentano geometry, the irradiated sample surface must sit on the goniometer’s reference plane within roughly ±25 µm. A holder that floats the sample even 100 µm too high produces a measurable 2θ shift (peak displacement is approximately Δ2θ ≈ −2s·cosθ/R, where s is the height error and R is the goniometer radius).
- Contribute as little signal as possible. A standard 1 mg powder smear on a glass slide can be drowned out by amorphous “humps” from the substrate. A well-designed holder either uses a low-scattering material (fused quartz, off-axis silicon) or geometrically deflects the diffracted beam away from the detector.
- Hold the sample without disturbing its texture. Pressing too hard introduces preferred orientation; back-loading and side-drift methods exist precisely because front-loading distorts intensity ratios for plate-shaped or needle-shaped crystallites.
The 30-second triage. If your XRD pattern shows a broad amorphous hump centred near 2θ ≈ 22° on a Cu source, suspect the holder before you suspect the sample. That feature is the silica glass background and is one of the most common artefacts in undergraduate XRD work.
2. The six types of XRD specimen holders
You will encounter dozens of part numbers from instrument vendors, but every holder reduces to one of six functional designs:
Type 1
Standard powder holder
A flat plate (typically aluminium, steel, or PMMA) with a recessed rectangular or circular well — usually 10×10 mm or 20×20 mm reception, 0.5–2 mm depth. Powder is back-loaded or front-loaded and the sample face is brought flush with the holder surface. The default holder for routine phase ID with mg-to-g sample sizes.
Type 2
Zero-background holder (ZBH)
A polished single crystal cut along a plane that does not satisfy any Bragg condition in the geometry (Si(510), Si(911), or quartz off-cut). Diffracted intensity from the holder is below the noise floor, so even sub-milligram samples can be measured. Mandatory for nano-powders, thin films, and trace contaminants.
Type 3
Low-background quartz holder
Fused quartz (JGS1 / JGS2) machined into a standard 50×35 mm or 45×35 mm format with shallow wells. Quartz is amorphous so it produces no sharp peaks, but it still gives a broad scattering hump near 22° 2θ. Substantially cheaper than ZBH and acceptable for samples ≥ 10 mg.
Type 4
Capillary holder (transmission)
A goniometer head that grips a quartz, glass, or kapton capillary (typically Ø 0.3–1.0 mm) for Debye–Scherrer / transmission geometry. Used for Mo or Ag radiation, air-sensitive samples, and any non-flat-plate Debye–Scherrer measurement on a 2D detector.
Type 5
Air-sensitive / dome holder
A flat holder fitted with a polymer dome (kapton or beryllium foil) that creates a hermetic chamber over the sample. The chamber is loaded inside a glove box and transferred to the diffractometer without exposing moisture-sensitive or pyrophoric powders to atmosphere.
Type 6
Specialty: clay, filter, capillary spinner
Clay holders use a roughened surface to retain oriented clay films for <001> basal-spacing work. Filter holders accept Ø 25–47 mm filter discs from indoor air or aerosol sampling. Spinner stages rotate a flat or capillary holder during measurement to improve crystallite-orientation statistics.
3. Zero-background holders (ZBH) — when you actually need one
A zero-background holder is a single crystal — almost always silicon — cut on a plane that does not satisfy Bragg’s law in the geometry of your diffractometer. The two cuts you will see in catalogues are Si(510) and Si(911); both are off-axis enough that no allowed reflection appears within the practical 2θ range of a Cu, Co, Cr, Fe, or Mo source. Quartz off-cut crystals (sometimes called “fused quartz ZBH”) can offer similar performance but are less common because high-purity Si wafers are cheaper and easier to polish.
Use a ZBH when
- Sample mass is < 5 mg, or it can only be deposited as a thin film < 50 µm thick.
- You need quantitative phase analysis (Rietveld) where holder background biases scale factors.
- You are looking for a minor phase < 1 wt% in a multi-component mix.
- Your sample is precious (forensic, archaeological, single-crystal fragments).
Skip the ZBH when
- You have ≥ 10 mg of well-crystallised powder; a low-background quartz plate is sufficient.
- You are doing routine phase ID where peak position matters more than peak height.
- Sample preferred orientation is the dominant error budget — a deeper well on a standard holder gives better powder statistics.
Practical tip. A ZBH is most valuable when sample < 1 mm³. Smear the powder in a drop of acetone, ethanol, or amyl acetate and let the solvent flash off. With a 5 mg ground powder, the resulting film is typically 50–100 µm thick and shows essentially no holder background. Avoid water — it can dissolve common analytes (sulfates, hydrates, halides) and re-precipitate them with new phases.
4. Low-background quartz holders — the workhorse for > 10 mg samples
Fused quartz holders sit between standard metal/PMMA holders and ZBH on cost and performance. They are the right choice when your sample mass is large enough to fill a 0.5–2 mm well but you still want to minimise the holder’s contribution.
Three things make quartz a good XRD-holder material:
- Amorphous structure. Fused quartz has no long-range order, so it cannot diffract sharp Bragg peaks. It only contributes a broad scattering hump.
- Low Z constituents. Si and O are low-atomic-number elements, so absorption and Compton scattering of Cu Kα are modest.
- No fluorescence. Unlike Fe-bearing steel holders under Cu radiation (which fluoresces strongly and raises baseline noise), quartz produces no characteristic fluorescence at any common laboratory wavelength.
| Property | Fused quartz (JGS1) | Optical glass (BK7-class) | Aluminium | Si(510) ZBH |
|---|---|---|---|---|
| Amorphous hump @ Cu Kα | Moderate (22°) | Strong (22°) | None (sharp peaks instead) | None |
| Sharp parasitic peaks | None | None | 3 strong (38°, 44°, 65°) | None in 5–80° |
| Cu fluorescence | None | None | None | None |
| Cost (50×35 mm plate) | $$ | $ | $ | $$$$ |
| Reusable / cleanable | Yes (acid) | Limited | Yes | Yes (alcohol) |
For pharma quality control, environmental analysis, and most academic phase ID work, a 50×35×2 mm fused-quartz plate with a 10×10×0.5 mm well is the default specification. MachinedQuartz keeps this geometry in stock as part number MQX010, with 5×5 mm (MQX009), 15×15 mm (MQX011), and 20×20 mm (MQX012) reception variants.
5. Specialty holders: capillaries, clay, filters & air-sensitive
Capillary (Debye–Scherrer / transmission)
A 0.3–1.0 mm diameter glass or quartz capillary, sealed at one end, is filled with powder, mounted on a goniometer head, and rotated during measurement. Transmission geometry is preferred for low-absorbing samples (organics, MOFs, polymers) and any work with a 2D detector. Quartz capillaries have lower background than borosilicate but are more expensive; the choice usually comes down to source wavelength: quartz is essential for Mo and Ag, optional for Cu.
Clay-mount and oriented holders
Clay-mineral analysis (kaolinite, illite-smectite, chlorite) depends on resolving the basal <001> reflections at low 2θ. Holders for clay work either have a roughened porous surface that grabs a clay slurry as it dries, or they accept a glass cover slip with a thin clay film deposited from suspension. Either way the goal is to keep clay platelets parallel to the holder surface so that the <001> reflections dominate.
Filter holders
For aerosol or air-quality work, the sample is deposited directly on a Ø 25, 37, or 47 mm filter membrane (cellulose, PTFE, or polycarbonate). A filter holder is a flat plate with a recess matching the filter diameter; the diffractometer “sees” both the filter material and the deposit, so a blank-filter background subtraction is mandatory.
Airtight / air-sensitive holders
Reactive samples (Li-ion electrode powders, organometallics, metal hydrides) must be loaded in a glove box and transferred without atmospheric exposure. Airtight holders use a thin polymer dome — kapton (5–25 µm) or beryllium foil — sealed against the holder body with an O-ring. Kapton has a broad amorphous hump near 5–6° and 14° 2θ that should be characterised before quantitative work; beryllium is essentially XRD-transparent but is toxic if abraded and is now restricted in many labs.
6. Material selection: quartz vs silicon vs glass vs PMMA
The four materials you will see in commercial XRD holders cover a wide range of cost and performance. The right choice depends on three questions: how much sample do I have, what radiation am I using, and what fluorescence and background can I tolerate.
| Material | Background | Cu Kα fluorescence | Heat / chemical resistance | Typical use |
|---|---|---|---|---|
| Single-crystal Si (ZBH) | None within 5–80° 2θ | None | Up to 1100 °C; inert to most | < 5 mg samples, thin films, trace phases |
| Fused quartz (JGS1/JGS2) | Broad hump near 22° | None | Up to 1100 °C; HF-soluble; acid-resistant otherwise | Routine phase ID with ≥ 10 mg, pharma QC |
| Optical glass (BK7-class) | Strong amorphous hump near 22° | None | Up to ~500 °C; alkali-soluble | Cheap, disposable, undergraduate lab |
| Aluminium / steel | 3+ sharp Bragg peaks (Al at 38°, 44°, 65°; Fe at 44°, 65°, 82°) | Steel fluoresces strongly under Cu | Excellent | Thick samples that fill the well; bulk QC |
| PMMA / polycarbonate | Broad polymer hump near 13° & 17° | None | Up to ~80 °C | Disposable, biological samples, low-temp work |
Why MachinedQuartz uses JGS1/JGS2 quartz for low-background holders
- JGS1 is high-purity electrically fused quartz with extremely low metal-impurity content (Fe < 1 ppm) — important when fluorescence under Cu Kα would raise the baseline.
- JGS2 is the standard optical-grade quartz suitable for general UV-Vis and XRD work where ultra-trace metals are not the limiting factor.
- Both grades are amorphous, mechanically polished, and free of internal stress that could introduce strain-broadening artefacts in long-exposure measurements.
For a comprehensive comparison of the JGS1 / JGS2 / JGS3 grades and their UV-Vis cut-offs, see our dedicated quartz UV cut-off guide; the same grade designations apply to XRD holder substrates.
7. Design rules: well depth, surface finish, and tolerance
A specimen holder is a piece of precision machining, not a generic flat plate. Three dimensions dominate the data quality:
Well depth
The depth determines how much sample is irradiated at low angles, where the X-ray penetration depth is large. As a rule of thumb:
- 0.2–0.3 mm — for ZBH equivalents and very small samples; minimises holder background but constrains sample mass to < 5 mg.
- 0.5 mm — the most common general-purpose depth; works for 10–50 mg powder samples.
- 1 mm — for thick powders, well-crystallised inorganics, and applications where preferred orientation is the limiting error.
- 2 mm — for “infinitely thick” samples, where you want the entire X-ray penetration depth in sample regardless of θ.
If the well is shallower than the X-ray penetration depth, you will see “transparency” peaks shifted toward higher 2θ. The textbook fix is to fill a deeper well; the field-practical fix is to use a higher-Z analogue or, on a Bragg-Brentano stage, increase the divergence slit.
Sample surface vs holder surface
The packed sample must sit at the same plane as the holder rim — flush, not recessed and not proud. A holder with a recess deeper than your loaded sample causes intensity loss at low 2θ (the beam misses some of the sample); a holder with a proud sample shifts every peak toward lower 2θ.
Surface finish & flatness
For Bragg-Brentano work, the holder rim flatness should be ≤ 5 µm over the irradiated area, and the surface roughness Ra ≤ 0.05 µm where the sample sits. MachinedQuartz polishes XRD-holder rims to optical-flat tolerance using the same lap-and-pitch process used for our cuvette windows.
OEM design tolerances we hold by default. Outer dimension ±0.1 mm; thickness ±0.05 mm; well dimension ±0.05 mm; well depth ±0.025 mm; rim flatness ≤ 5 µm; sample-face roughness Ra ≤ 0.05 µm. Tighter tolerances are available on request and are routine for instrument-OEM contracts.
8. Instrument compatibility — Rigaku, Panalytical & Bruker
The three major XRD instrument families have evolved their own holder geometries over decades, and the formats are not interchangeable without an adapter. Outer dimensions are the universal constraint; the well size and depth can be customised within each format.
Rigaku — 50 × 35 × 2 mm “universal” format
Rigaku Smartlab, MiniFlex (5th and 6th generations), Ultima IV, and SuperLab platforms accept a 50×35×2 mm holder as the native format. MachinedQuartz part numbers in this family include MQX009 (5×5 well), MQX010 (10×10), MQX011 (15×15), MQX012 (20×20), MQX060 (20×20×1 mm), MQX061 (10×10×1 mm), and MQX064 / MQX065 for shallow 0.2 mm wells. Other Rigaku-compatible plates use 50×35×1.6 mm thickness for use with the spinner accessory: MQX047 (5×5 well) and MQX050 (Ø10 round well).
Malvern Panalytical — 45 × 35 × 2 mm format (PW1813 / Empyrean)
Empyrean, X’Pert³ Powder, X’Pert³ MRD, and the older PW1813 / X’Pert Pro use a 45×35×2 mm holder as the native format. Common MQ part numbers: MQX019 (5×5), MQX020 (10×10), MQX021 (15×15), and MQX022 (20×20). Customised quartz/optical-glass variants (MQX057/MQX058) provide a 20×15 rectangular sample reception for elongated specimens.
Bruker AXS — 30 × 20 × 4 mm DaVinci format
Bruker D8 Advance, D8 Endeavor, and D2 Phaser (with A100B36 adapter) use a 30×20×4 mm format. The deeper 4 mm body lets the well sit lower in the holder body; typical wells are 26×13 mm rectangular at 2 mm depth — covered by MQX056. The Bruker DaVinci platform also supports a smaller 20×15 mm sub-format for high-throughput batch measurement.
46 × 36 × 3 mm — extended sample reception
For applications requiring slightly more sample mass while staying close to a Panalytical-compatible footprint, the 46×36×3 mm format with a 20×15 well and 0.8 mm depth is available as MQX023.
If you are not sure which format your goniometer takes, measure the existing holder before ordering. Outer length × width × thickness is the only dimension that matters for physical fit; the well and depth can always be customised. Send your existing-holder dimensions to us and we will match them in fused quartz, ZBH-equivalent quartz off-cut, or optical glass.
Rigaku 50×35MQX010 — Universal Quartz
50×35×2 mm · 10×10 mm well · 0.5 mm depth · JGS quartz
View MQX010 →
Panalytical 45×35MQX020 — Empyrean / X’Pert
45×35×2 mm · 10×10 mm well · 0.5 mm depth · optical glass
View MQX020 →
Bruker 30×20MQX056 — D8 DaVinci
30×20×4 mm · 26×13 mm well · 2 mm depth · optical glass
View MQX056 →9. Custom XRD specimen holders from MachinedQuartz
The 60+ part numbers listed in the MachinedQuartz XRD-holder catalogue cover the most common Rigaku, Panalytical, and Bruker geometries with quartz or optical-glass substrates and well sizes from 5×5 mm to 26×13 mm. If your goniometer uses a non-standard format, or you need a different material (single-crystal quartz off-cut, sapphire, JGS3 IR-grade), our standard custom workflow handles unique designs.
What we manufacture in-house
- Outer dimensions from 15×15 mm up to 80×60 mm.
- Thickness from 1.0 mm to 6 mm.
- Wells from Ø 5 mm to 30×30 mm (rectangular, square, or round).
- Depths from 0.1 mm to 3 mm, ±0.025 mm tolerance.
- Substrates: JGS1, JGS2, JGS3 fused quartz; quartz off-cut for ZBH-equivalent performance; sapphire for high-temperature in-situ XRD; optical glass; CaF₂ and BaF₂ for Mo / W radiation.
- Surface finishes from blank-cut to optical-flat polished (rim flatness ≤ 2 µm).
Lead times
- Stock catalogue items: 3–7 days from order to ship, US and EU.
- Custom geometries based on standard formats: typically 12–18 working days.
- Net-new designs requiring tooling: 25–35 working days; we send a free 2D drawing for sign-off before machining.
Need a holder that does not exist in any catalogue?
Send a sketch, a sample drawing, or your existing-holder dimensions. We’ll respond within one business day with a quote, lead-time, and a free CAD review.
Browse stock holders → Request custom quote →Most-ordered XRD holders
MQX009
Rigaku 50×35 · 5×5 well · 0.5 mm
MQX011
Rigaku 50×35 · 15×15 well · 0.5 mm
MQX012
Rigaku 50×35 · 20×20 well · 0.5 mm
MQX021
Panalytical · 15×15 well · 0.5 mm
MQX050
Rigaku 50×35 · ⌀10 round well · 0.5 mm
MQX064
Rigaku 50×35 · 20×20 well · 0.2 mm shallow
For orders that combine specimen holders with quartz cuvettes, optical windows, or quartz plates, see the broader custom quartz cuvettes and cuvette fabrication method pages — the same tolerance specifications and JGS-grade materials are used across the MachinedQuartz product line.
10. Frequently asked questions
What is a zero-background holder (ZBH) made of?
A zero-background holder is a single-crystal substrate cut along a plane that produces no allowed Bragg reflection in your diffractometer’s geometry. The two most common cuts are silicon (510) and silicon (911); both give a flat baseline within the 5–80° 2θ range used for laboratory Cu, Co, Cr, Fe, and Mo radiation. Quartz off-cut crystals are also available and behave similarly, though they are less common because high-purity Si wafers are cheaper to source and polish.
Why does my XRD pattern have a broad hump near 22° 2θ?
That hump is the amorphous SiO₂ scattering signature, and it is almost always coming from your specimen holder if you are using a glass slide, fused-quartz plate, or a glass-fibre filter membrane. To confirm: run the empty holder. If the hump is still there, the holder is the source. To eliminate it, switch to a zero-background holder (Si single crystal) or, for ≥ 10 mg samples, fill the well of a low-background quartz plate so the sample’s own diffraction dominates over the holder’s amorphous contribution.
How much sample do I need for a low-background quartz holder vs. a ZBH?
Use a low-background quartz holder for 10 mg or more of well-crystallised powder; the holder background is small relative to sample peaks at this mass. Use a zero-background holder for samples below 5 mg, for thin films deposited from solvent suspensions, or for trace-phase analysis where you need to detect a minor phase below 1 wt%. Between 5 mg and 10 mg either holder works; choose ZBH if the sample is precious or if you need quantitative Rietveld results.
Can I use the same XRD holder on a Rigaku, Panalytical, and Bruker instrument?
Not without an adapter. The three vendors use different native outer dimensions: Rigaku (50×35×2 mm), Panalytical (45×35×2 mm), and Bruker DaVinci (30×20×4 mm). Universal carrier adapters exist for some combinations, but they reduce holder rigidity and change the sample-to-detector distance, which can shift peak positions. The cleanest workflow is to keep separate holder sets matched to each instrument and to specify the holder format when ordering replacement or custom holders.
What is the typical well depth for an XRD specimen holder?
The most common general-purpose well depth is 0.5 mm, which suits 10–50 mg powder samples. Use 0.2–0.3 mm for ZBH-style minimum-mass measurements, 1 mm for thicker powders or high-θ work where penetration depth matters, and 2 mm for samples where you want the entire X-ray penetration depth to be in sample regardless of angle. A shallow well combined with a low-density sample produces transparency-shift artefacts, so match the well to the sample.
Why do aluminium holders show sharp peaks while steel ones raise the baseline?
Aluminium is crystalline and gives three strong Bragg peaks at 38.5°, 44.7°, and 65.1° 2θ on Cu Kα — they are sharp and easily mistaken for a sample phase. Steel is also crystalline, but its iron content also fluoresces strongly under Cu radiation, producing characteristic Fe-Kα emission that the detector counts as background noise. Both effects can be eliminated by switching to fused quartz, single-crystal silicon, or a glass holder, depending on how clean a baseline you need.
How should I clean and reuse a quartz XRD holder?
For routine powder samples, brush out the well with a soft camel-hair brush and rinse with 2-propanol or ethanol. For stubborn deposits, soak in 5 % nitric acid for 30 minutes, rinse with deionised water, then ethanol. Avoid hydrofluoric acid — it dissolves fused quartz. Avoid prolonged alkaline soaks because some glass-class substrates can develop micro-etching that affects flatness. Inspect the rim flatness with a straight-edge or interferometric reference before re-running quantitative work.
Are airtight XRD holders compatible with all instruments?
Most airtight holders are sized to fit one of the three universal formats (Rigaku 50×35, Panalytical 45×35, or Bruker 30×20). The dome itself adds a few millimetres of height, so the goniometer must be tall enough to clear the dome at the highest 2θ value you plan to scan. Kapton domes work well for Cu Kα; beryllium domes are XRD-transparent but are increasingly restricted because of the toxicity of Be dust. If you are scanning above 80° 2θ, verify dome clearance before ordering.
Can a custom XRD specimen holder be made from sapphire or CaF₂?
Yes. Sapphire (single-crystal Al₂O₃) is the standard choice for in-situ heating XRD up to 1500 °C; cut on the (0001) basal plane it shows no diffraction in the standard 5–80° 2θ range. CaF₂ and BaF₂ are used when working with shorter-wavelength radiation (Mo, Ag, W) where typical Si or quartz holders show absorption edges. MachinedQuartz fabricates sapphire and CaF₂ holders to the same Rigaku/Panalytical/Bruker outer-dimension formats; lead times are typically 25–35 working days for non-standard substrates.
How do I order a holder when my goniometer is from an unusual vendor?
Measure the existing holder’s outer length, width, and thickness with a calliper (±0.05 mm), measure the well dimensions and depth, and note any features (mounting cut-outs, dowel pin holes, kinematic seats). Send the dimensions and a photograph of both faces to our team via the contact form. We typically respond within one business day with a free 2D drawing for sign-off and a firm lead time. The same workflow handles legacy Stoe, Inel, and Seifert formats that no longer have a standard catalogue equivalent.
11. Authoritative references
- Pecharsky, V. K., & Zavalij, P. Y. (2009). Fundamentals of Powder Diffraction and Structural Characterization of Materials, 2nd ed., Springer. Chapters 11–13 cover holder geometry and sample-preparation artefacts.
- Klug, H. P., & Alexander, L. E. (1974). X-Ray Diffraction Procedures for Polycrystalline and Amorphous Materials, 2nd ed., Wiley. Foundational text on Bragg-Brentano geometry and specimen-displacement errors.
- International Centre for Diffraction Data (ICDD). Practical X-Ray Fluorescence and X-Ray Diffraction Sample Preparation Guide. Reference for clay, filter, and air-sensitive holder workflows.
- Bruker AXS. XRD Specimen Holders — DaVinci Design. OEM catalogue describing standard, low-background, airtight, and capillary holders for D8 platforms.
- Malvern Panalytical. Sample preparation and holder accessories for Empyrean. Application note on PW1813-format holders and zero-background inserts.
- Rigaku Corporation. Standard Sample Holder Catalogue for Smartlab and MiniFlex. Reference for 50×35 holder dimensions.