Authorised Indian Distributor
Saxsons Group
New Delhi, India · Since 1997
MAX 4000 PlusReference Electrometer
Versatile and accurate. One of the most widely used reference electrometers in radiotherapy — covering absolute dosimetry, patient dosimetry, SRS and all QA protocols from daily output to annual calibration.
Key Features
- Reference-grade for all radiation therapy dosimetry applications
- Exceptional current range: 0.001 pA to 500.00 nA
- Charge range: 0.01 pC to 999,999 nC
- 0.1% repeatability — exceeds TRS-398 and TG-51 requirements
- Leakage current less than 1 fA — lowest in class
All Features
- Reference-grade for all radiation therapy dosimetry applications
- Exceptional current range: 0.001 pA to 500.00 nA
- Charge range: 0.01 pC to 999,999 nC
- 0.1% repeatability — exceeds TRS-398 and TG-51 requirements
- Leakage current less than 1 fA — lowest in class
- Digital filter technology eliminates RF and environmental noise
- Redesigned display for improved readability and clarity
- MAX COMM™ software for dose/dose-rate control and data logging
- Remote electrometer operation via MAX COMM interface
- Chamber and detector management built-in
- Stereotactic and small-field dosimetry compatible
- Suitable for absolute, relative and patient dosimetry
Technical Specifications
| Current range | 0.001 pA to 500.00 nA |
| Charge range | 0.01 pC to 999,999 nC |
| Repeatability | 0.1% |
| Leakage current | < 1 fA |
| Noise reduction | Digital filter technology |
| Display | Redesigned high-visibility display |
| Software | MAX COMM™ — dose, dose-rate, logging, remote |
| Remote operation | Yes — via MAX COMM |
| Chamber management | Built-in detector database |
| Applications | Absolute, relative, patient dosimetry; SRS; daily/monthly/annual QA |
| Standards | TRS-398, TG-51, TG-142 compatible |
Applications
One electrometer — the full dosimetry spectrum
Absolute Reference Dosimetry
TRS-398 and TG-51 reference dosimetry with Farmer-type chambers. 0.001 pA minimum current resolves even the smallest ionisation signals.
Annual & Monthly Machine QA
Accurate output measurements for TG-142 annual and monthly QA. Remote operation via MAX COMM frees the physicist from the vault during irradiation.
Patient Dosimetry
In-vivo and point-dose patient dosimetry with compatible diode and IC detectors. Data logging to MAX COMM for audit trail.
SRS / Stereotactic Applications
Measures very small ionisation currents (< 1 pA) required for small-field SRS chamber characterisation without saturation or noise.
Daily Output Monitoring
Fast digitisation with digital filter for clean, repeatable daily output measurements. Chamber correction factors stored in device memory.
Electron Beam Dosimetry
Full charge integration mode for pulsed electron beam measurements. Compatible with parallel-plate chambers for electron reference dosimetry.
Why MAX 4000 Plus?
From the smallest small-field SRS measurement to the largest calibration beam, the MAX 4000 Plus covers nine decades of current without switching external hardware.
Sub-femtoampere leakage is the lowest specification available in a clinical electrometer. Measurements near detection threshold are not polluted by instrument leakage.
Three decades of precision electrometer design. The MAX 4000 Plus is in routine clinical use at thousands of radiotherapy centres worldwide.
MAX 4000+
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FAQ
Reference-grade radiotherapy electrometer — questions we hear from Indian medical-physicist teams
What an electrometer does in the dosimetry chain, why TRS-398 / TG-51 need a reference-grade instrument, which chamber types and workflows it reads, and how MAX 4000+ is supplied across India.
Q.What does an electrometer actually do in a radiotherapy dosimetry programme?
An ion chamber measures dose by accumulating tiny electrical charges as radiation ionises the gas inside the chamber cavity. The electrometer is the precision instrument that reads those charges — typically in the picocoulomb to nanocoulomb range. Every reference-dosimetry measurement (linac output calibration, TRS-398 / TG-51 machine calibration, in-vivo dose reconstruction) reads back from an electrometer. Its accuracy is the floor of the department's entire dosimetry chain.
Q.Why does TRS-398 / TG-51 need a reference-grade electrometer rather than a generic multimeter?
IAEA TRS-398 and AAPM TG-51 reference-dosimetry protocols expect the electrometer accuracy to sit well inside 0.5 % — the target overall dose-delivery uncertainty budget is around 3 %, with the electrometer as one contributor. A generic multimeter typically drifts several percent between calibrations and is not traceable to a primary standards laboratory. A reference-grade electrometer like MAX 4000+ is NIST/PTB-traceable, temperature-compensated and bias-stabilised so its contribution to the dose-uncertainty budget stays small.
Q.Which chambers and workflows does MAX 4000+ read?
MAX 4000+ reads the standard cylindrical Farmer chambers, parallel-plate chambers and small-volume SRS chambers used across the clinic. Bias-voltage output covers positive and negative polarity so leakage and recombination corrections can be applied per TRS-398 method. Charge integration and current-mode read-out support both routine output constancy checks and slow-dose in-vivo measurements.
Q.Is MAX 4000+ enough as the only electrometer on the physicist bench?
For a single-linac / single-cobalt department — yes. Reference dosimetry, commissioning, annual output verification, in-vivo checks and small-field / SRS dosimetry all run from the same electrometer with the appropriate chamber. Larger multi-machine departments typically stock a second unit as a QC-check backup — an electrometer failure on a machine-calibration morning otherwise takes the day off the QA schedule.
Q.How is MAX 4000+ supplied and supported in India?
Distributed across India by Saxsons Group. Supply covers the electrometer, chamber-compatibility bench-test, NIST/PTB-traceable calibration certification and applications training for the physicist team. Passive medical device — imported under CDSCO Medical Devices Rules 2017.
MAX 4000 Plus supplier in India — Saxsons Group
Saxsons Group has supplied radiotherapy equipment to over 1,000 Indian hospitals since 1988. Every consignment of MAX 4000 Plus ships with cold-chain logistics, AERB import documentation, CDSCO registration references and a Certificate of Analysis delivered before dispatch — the paperwork your radiation-safety and procurement teams need, pre-assembled.
- Nationwide delivery footprint — every metro and tier-2 city in India, scheduled to your treatment / procedure calendar.
- AERB & CDSCO documentation — import licence, radiation-safety paperwork and RSO briefing pre-assembled for the audit file.
- 40+ years in Indian oncology — long-standing supply relationships with AIIMS, Tata Memorial, and hundreds of tertiary-care centres.
- Single point of accountability — one purchase order, one delivery contact, one after-sales team across the whole product family.
Also supplied by Saxsons Group across India
The reference electrometer for Indian radiotherapy
Contact Saxsons Group for pricing, AERB import documentation, calibration traceability and installation support.