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Product

Medical Micro-Coaxial & Ultra-High-Vacuum CablesUHV ≤ 10⁻¹⁰ mbar-269 to +250 °C (4 K)10 MGy Radiation-Hard

301-KAP50 / 301-KAP50-S Polyimide UHV 50 Ohm Coaxial CableUHV ≤ 10⁻¹⁰ mbar · 50 Ω ± 2.5 Ω · Ø 1.95 / 2.25 mm · -269 °C (4 K) to +250 °C ·

301-KAP50 and 301-KAP50-S are 50 Ω ultra-high-vacuum (UHV ≤ 10⁻¹⁰ mbar), cryogenic (-269 °C / 4 K liquid helium to +250 °C bakeout), and radiation-hard (10⁷ Gy / 10⁹ rad) miniature coaxial cables insulated with fused aromatic polyimide film—available

EMC screen
Low-EMC design
Flame-retardant
Approved
Order designation
301-KAP50 Smooth Polyimide Outer (Ø 1.95 mm)
Outer Ø ≈
1.95 mm
Metal weight
6.2 kg/km
Total weight ≈
10.5 kg/km
Min. bend R (fixed)
10 mm
All sizes (4)
Request a quoteDatasheetWhatsApp
Engineering reply in 2 business hoursCut-to-length export drumsEN 10204 3.1 certificate per drum
Vacuum rating
≤ 10⁻¹⁰ mbar UHV
TML < 0.3 % · CVCM < 0.02 %
Impedance Z₀
50 Ω ± 2.5 Ω
DC to 5 GHz (Ø 1.95 / 2.25 mm)
Temp. range
-269 to +250 °C
4 K cryogenic to +250 °C bakeout
Radiation dose
Up to 10⁷ Gy
Halogen-free aromatic polyimide
Velocity / Cap.
65 % · 105 pF/m
0.60 mm (19×0.12) Ag-Cu center
Outer shield (-S)
AISI 316L SS
Abrasion & grounding guard

Typical values for this cable type, based on UHV Coaxial Spec (≤ 10⁻¹⁰ mbar) / MIL-DTL-17 Ref. — confirmed in the datasheet and quotation for your order.

Application fit

Is 301-KAP50 / 301-KAP50-S right for your machine?

Engineered for synchrotron beamlines, particle accelerators, cryogenic dilution refrigerators (4 K), scanning tunneling / atomic force microscopes (UHV STM/AFM), space flight payloads, and

Fixed installation

Suitable

Vented non-trapping polyimide construction evacuates rapidly to ≤ 10⁻¹⁰ mbar without virtual leaks.

Switchgear & control cabinet wiring

Suitable

Routes from UHV CF-flange SMA/BNC/SHV feedthroughs to in-vacuum detectors, piezo stages, and RF pickups.

Furnace, kiln & high-temp zone

Suitable

Withstands repeated +200 °C to +250 °C UHV chamber bakeout cycles without outgassing hydrocarbons or halogens.

Energy chain / drag chain

With conditions

Supports in-vacuum translation stages and manipulator gimbals at ≥ 15 mm bend radius.

Typical machinesSynchrotron & Particle AcceleratorsUHV Surface Science (XPS, ARPES, STM)Cryogenic 4 K Quantum & Detector DewarsSemiconductor EUV Lithography VacuumSpacecraft & Satellite Payload Harnesses

Construction

Layer by layer

19×0.12 mm (Ø 0.60 mm, 24 AWG) silver-plated oxygen-free copper center conductor, Ø 1.48 mm fused polyimide dielectric, ≥ 90 %

12345
Schematic, not to scale — generated from the layer data
#LayerMaterial & reference
1Stranded Ag-OFC center conductor (2419 × 0.12 mm (Ø 0.60 mm, 0.22 mm²) ultra-clean silver-plated oxygen-free copperUHV Coax Spec
2Multi-layer fused polyimide dielectricPrecision wrapped and thermally sealed aromatic polyimide film, Ø 1.48 mm (εr ≈ 3.4, 65UHV Coax Spec
3Silver-plated copper RF shield braid0.10 mm silver-plated oxygen-free copper wire braid (≥ 90 % coverage)UHV Coax Spec
4Fused amber polyimide UHV jacketSealed aromatic polyimide outer sheath, amber-gold (Ø 1.95 mm on 301-KAP50)UHV Coax Spec
5AISI 316L stainless-steel overbraidNon-magnetic AISI 316L stainless-steel wire outer braid (Ø 2.25 mm on 301-KAP50-S) forUHV Coax Spec

301-KAP50 (Smooth Polyimide Outer Jacket, Ø 1.95 mm)

Electrically isolated amber polyimide outer surface so the RF shield floats from vacuum chamber walls.

301-KAP50-S (316L Stainless-Steel Overbraided, Ø 2.25 mm)

Adds an external non-magnetic 316L stainless-steel braid for flange chafe protection and static charge bleed.

Technical data

Ratings & operating limits

Typical values: Typical values for this cable type, based on UHV Coaxial Spec (≤ 10⁻¹⁰ mbar) / MIL-DTL-17 Ref.. Values for your order are confirmed in the datasheet and quotation.

Electrical

Characteristic impedance Z₀
50 Ω ± 2.5 Ω
Nominal capacitance
105.0 pF/m (32.0 pF/ft)
Velocity of propagation (VoP)
65.0 % (5.13 ns/m delay)
Center / shield DC resistance
≤ 86 Ω/km / ≤ 26 Ω/km at 20 °C
Max. operating voltage
1,200 V DC / 850 V rms AC (in air/UHV)
Dielectric withstand test
2.0 kV rms at 50/60 Hz

Thermal

Operating temperature range
-269 °C (4 K) to +250 °C continuous
Short-term bakeout peak
+300 °C in vacuum
Cryogenic thermal shock
Direct immersion in LN₂ (77 K) & LHe (4 K)
Outgassing (ASTM E595 / ECSS)
TML < 0.30 % · CVCM < 0.01 % (post-bake)
UHV pressure compatibility
≤ 1 × 10⁻¹⁰ mbar (10⁻⁸ Pa)
Flammability in air
Self-extinguishing UL 94 V-0

Mechanical

Center conductor stranding
19 × 0.12 mm Ag-OFC (Ø 0.60 mm, 24 AWG)
Dielectric diameter
1.48 mm ± 0.05 mm
Outer diameter (KAP50 / KAP50-S)
1.95 mm ± 0.08 mm / 2.25 mm ± 0.10 mm
Min. bend radius (fixed / dynamic)
10 mm (5×D) / 20 mm (10×D)
Nominal weight (KAP50 / KAP50-S)
10.5 kg/km / 16.8 kg/km
Connector compatibility
UHV peek/ceramic SMA, SMB, Microdot, BNC

Resistance

Ionizing radiation resistance
Up to 10⁷ Gy (10 MGy / 10⁹ rad) gamma/e⁻
Halogen & fluorine free
Zero F⁻ outgassing under beam bombardment
Magnetic permeability
Non-magnetic Ag-Cu & annealed 316L SS
Solvent & ultrasonic cleaning
Compatible with acetone, IPA & UHV clean
Abrasion protection (-S version)
316L stainless braid resists sharp ports
RoHS / REACH status
RoHS 3 compliant

Reference standards

Vacuum outgassing standard
ASTM E595 / NASA SP-R-0022A / ECSS-Q-ST-70-02
Radiation endurance reference
CERN / DESY / ESRF beamline qualification
Coaxial RF standard
IEC 61196-1
Conductor standard
ASTM B298 oxygen-free silver-plated Cu
Stainless overbraid standard
EN 10088 / AISI 316L non-magnetic
Quality certification
UHV cleanroom certificate + EN 10204 3.1

Identification

Dielectric colour
Amber-gold translucent polyimide
Outer appearance (301-KAP50)
Amber-gold polyimide film
Outer appearance (301-KAP50-S)
Bright metallic AISI 316L stainless braid
Packaging
UHV-cleaned, double-bagged in cleanroom PE
Standard lengths
5 m, 10 m, 25 m, 50 m, 100 m
Batch traceability
Cleanroom lot number & HV/TDR test sheet

Sizes

4 standard configurations (301-KAP50 / 301-KAP50-S)

Dimensional, physical and high-frequency electrical parameters for 301-KAP50 / 301-KAP50-S per UHV Coaxial Spec (≤ 10⁻¹⁰ mbar) / MIL-DTL-17 Ref..

Dimensions & construction
Order designationConstruction / VariantConductorOuter Ø ≈
mm		Metal
kg/km		Weight ≈
kg/km		Min. bend R
fixed mm		Enquiry
Standard 301-KAP50 / 301-KAP50-S variants
301-KAP50 Smooth Polyimide Outer (Ø 1.95 mm)50 Ω Ag-Cu Braid + Polyimide Jacket24 AWG (19×0.12 Ag-Cu)1.956.210.510
301-KAP50-S With 316L SS Outer Braid (Ø 2.25 mm)50 Ω Ag-Cu Braid + Polyimide + 316L SS24 AWG (19×0.12 Ag-Cu)2.256.216.811
310-PEEK50-TRIAX PEEK UHV Triaxial Sister50 Ω Dual Guard Braids (PEEK UHV)26 AWG (Ø 0.48 Ag-Cu)2.9511.519.515
RG-196A/U Non-Radiation PTFE Coax (Ø 2.03 mm)50 Ω Single SPC Braid (PTFE)30 AWG (7×0.10 SCCS)2.034.28.910
  • Typical values for this cable type; dimensions and weights for your order are confirmed in the quotation.
  • Dimensions and weights are nominal production values subject to manufacturing tolerances per UHV Coaxial Spec (≤ 10⁻¹⁰ mbar) / MIL-DTL-17 Ref..

Quality & approvals

Testing & inspection

Routine tests on every production length, sample and type tests per batch — documented on an EN 10204 3.1 inspection certificate.

  1. ConductorClass 5 stranding
  2. Spark test100 % in-line
  3. Lay-upCores, earth, fillers
  4. SheathingInner, braid / screen, outer
  5. Electrical testsAC voltage, resistance
  6. DimensionsOD, wall thickness
  7. Inspection documents & dispatchDrum & dispatch
Testing & inspectionTest value / referenceFrequency
Routine tests
TDR characteristic impedance & 2.0 kV HV test50 Ω ± 2.5 Ω; 2.0 kV rms AC without breakdownEvery coil
Hydrocarbon-free UHV ultrasonic cleaning checkCertified free of drawing lubricants, silicones, and halogensEvery coil
Sample tests
Residual gas analysis (RGA) & ASTM E595 outgassingCompatible with ≤ 10⁻¹⁰ mbar UHV after +200 °C bakeoutPer batch
Liquid helium (4 K) to +250 °C thermal shockZero polyimide delamination or shield fracture over 50 cyclesQualification

Inspection certificate

Issued with every drum, listing the routine test results for that length.

Product approvals

UHV ≤ 10⁻¹⁰ mbar CertifiedASTM E595 / ECSS-Q-ST-70-0210 MGy Radiation-Hard

Company certificates

ISO 9001ISO 14001ISO 45001VDE marks approvalUL / cULCE · LVD / EMC

Marking & supply

Ordering & delivery

Sheath marking

TEBAOFLEX 301-KAP50 / 301-KAP50-S 50 OHM
Delivery form
Spools, reels or export wooden drums
Standard reel lengths
100 m · 305 m (1000 ft) · 500 m · 1000 m
MOQ
100 m (stock) · 305–500 m (production)
Lead time
1–3 weeks ex-works
Incoterms
EXW, FCA, FOB, CIF, DAP

Technical documents

Downloads

PDF301-KAP50 / 301-KAP50-S Polyimide UHV 50 Ohm Coaxial Cable – technical datasheet4 sizes · construction, technical data, approvalsXLSX301-KAP50 / 301-KAP50-S spec data (Excel)All 4 sizes with dimensions and data, for your BOM or quotation
Revision
2026-10-20
Updated
2026-10-20

FAQ

Questions engineers ask first

Not covered here? Send your drawing — an engineer replies within 2 business hours.

Why is polyimide-insulated 301-KAP50 required in synchrotrons and particle accelerators instead of PTFE coax like RG-316?
Under ionizing radiation above ~10³ Gy (10⁵ rad), PTFE undergoes main-chain scission, turns brittle, and outgasses corrosive fluorine gas that poisons UHV ion pumps and optics; aromatic polyimide in 301-KAP50 is 100 % halogen-free and withstands up to 10⁷ Gy (10 MGy) while maintaining ≤ 10⁻¹⁰ mbar UHV cleanliness.
When should I choose 301-KAP50 vs 301-KAP50-S?
Choose 301-KAP50 (smooth polyimide outer jacket, Ø 1.95 mm) when the coaxial shield must remain electrically isolated from grounded chamber walls to prevent ground loops; choose 301-KAP50-S (with AISI 316L stainless-steel outer braid, Ø 2.25 mm) when routing across sharp vacuum port edges or when draining stray electron/ion beam charge to chamber ground.
Can 301-KAP50 be used from 4 K liquid helium cryostats up to +250 °C bakeout?
Yes, aromatic polyimide remains flexible down to 4 K (-269 °C) without cracking and withstands repeated +200 °C to +250 °C UHV bakeout cycles without softening. Each production reel undergoes sweep-frequency impedance and return-loss verification, dielectric spark testing, and dimensional inspection before dispatch with an EN 10204 3.1 test certificate.
How is the cable prepared for direct UHV installation?
Every length is manufactured without hydrocarbon lubricants, ultrasonically cleaned, baked, and sealed in cleanroom double polyethylene bags ready for UHV chamber assembly. Each production reel undergoes sweep-frequency impedance and return-loss verification, dielectric spark testing, and dimensional inspection before dispatch with an EN 10204 3.1 test certificate.

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301-KAP50 / 301-KAP50-S Polyimide UHV 50 Ohm Coaxial Cable

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