The Ametek / EG&G / ORTEC 142PC is a low-noise, charge-sensitive preamplifier engineered for proportional counter detection systems. It delivers exceptional signal-to-noise performance with typical noise of 295 rms electrons at 0 pF, rising to 450 rms electrons at 100 pF. The unit provides 4 V/pC sensitivity through dual interchangeable energy and timing outputs, with output rise times of 25 ns (0 pF) and 150 ns (100 pF). Integral nonlinearity remains within ±0.05% across its ±7 V output range, while temperature stability is maintained to ±50 ppm/°C from 0 to 50°C. The preamplifier accepts detector bias up to ±3000 V isolation and accommodates dynamic input capacitance to 1000 pF, making it ideal for soft X-ray and low-energy gamma-ray spectroscopy.
Technical Specifications
Noise Performance
• Typical: 295 rms electrons (0 pF); 450 rms electrons (100 pF)
• Guaranteed: <340 rms electrons (0 pF); <485 rms electrons (100 pF)
Signal Characteristics
• Sensitivity: 4 V/pC (nominal, both outputs)
• Rise Time: 25 ns (0 pF); 150 ns (100 pF) — measured 10% to 90%
• Output Linear Range: ±7 V
• Integral Nonlinearity: ≤±0.05%
• Open Loop Gain: ≥40,000
Dynamic Performance
• Dynamic Input Capacitance: 1000 pF
• Temperature Instability: ≤±50 ppm/°C (0 to 50°C)
• Detector Bias Isolation: ±3000 V
Power
• +24 V @ 30 mA; –24 V @ 10 mA; +12 V @ 15 mA; –12 V @ 15 mA
• Powered via NIM bin, ORTEC amplifier, or Model 4002P Portable Power Supply
Connectors & Outputs
• INPUT/BIAS: SHV connector
• ENERGY & TIMING: Dual BNC outputs (93 Ω impedance, interchangeable)
• TEST: BNC input (Rin = 93 Ω)
• Power Cable: 3 m captive; longer lengths available
– Key Features
• Dual output configuration supports simultaneous energy and timing discrimination
• Opposite polarity energy output; same-polarity timing output
• Built-in test input for system calibration without detector connection
• Compact form factor: 4.5 × 13.2 × 10.0 cm; 0.65 kg net weight
– Typical Applications
• Soft X-ray spectroscopy
• Low-energy gamma-ray detection
• Proportional counter-based nuclear and particle physics experiments
• Multi-parameter pulse processing systems
– Compatibility & Integration
Designed specifically for proportional counter systems. Compatible with ORTEC NIM modules and main amplifiers. Powered through standard NIM bin interfaces or standalone with the Model 4002P Portable Power Supply.
