سنسور و مبدل سنسور تخصصی

Product Attributes

Introduction

Large-area high-speed detectors achieve minimum junction capacitance through full depletion, enabling fast response times. They can operate at higher reverse voltages up to the maximum allowable value to achieve even faster nanosecond response times. The high reverse bias voltage increases the effective electric field across the junction, thereby reducing the charge collection time in the depletion region. Notably, this requires no sacrifice in high responsivity or active area size.

Large-area radiation detectors can also be fully depleted for measuring high-energy X-rays, gamma rays, and high-energy particles such as electrons, alpha rays, and heavy ions. These types of radiation can be measured using both indirect and direct methods.

In the indirect high-energy radiation measurement method, the detector is coupled to a scintillator crystal that converts high-energy radiation into detectable visible wavelengths. The device is mounted on a ceramic substrate and covered with a layer of transparent epoxy to achieve good optical coupling with the scintillator. This method is widely used for the detection of high-energy gamma rays and electrons. The scintillator type and size can be selected based on the radiation type and intensity.

For direct high-energy radiation measurement, the PIN-RD100 and PIN-RD100A can also be used without epoxy or a glass window for direct measurement of high-energy radiation such as alpha rays and heavy ions. After entering the active area, radiation travels in a straight line deep into the silicon material, losing energy along the path. The amount of energy loss and penetration depth are determined by the radiation type and intensity. To fully measure the radiation dose, the depletion layer must be deep enough to cover the entire track from the entry point to the stopping point. This requires applying a high bias voltage to fully deplete the detector. Despite having a large active area and requiring high bias voltage, these devices exhibit ultralow dark current, low capacitance, and low series resistance.

In addition to high-energy particle detection, the PIN-RD100 and PIN-RD100A are also excellent choices for applications requiring detection in the 350 to 1100 nm wavelength range with large active areas and high speed. These detectors can be coupled with charge-sensitive preamplifiers or low-noise op-amps. Indirect measurement configurations are also demonstrated using scintillator crystals.

For direct detection of high-energy particles, the preamplifier is a FET-input op-amp, followed by one or more amplification stages as needed, or a commercial charge-sensitive preamplifier. Counting efficiency is proportional to the incident radiation power. An appropriate reverse bias voltage must be selected to achieve the optimal signal-to-noise ratio. For low-noise applications, all components should be enclosed in a metal enclosure. In addition, the bias power supply should be a simple battery or a DC supply with extremely low ripple. The detector should also be operated in photovoltaic mode.

The indirect detection circuit is very similar to the direct detection circuit, with the difference that the photodiode is coupled to a scintillator. The scintillator converts high-energy X-rays and/or gamma rays into visible light. Suitable scintillators include CsI(TL), CdWO4, BGO, and NaI(TL). The amplifier should be a FET-input op-amp followed by one or more amplification stages, or a commercial charge-sensitive preamplifier. The output voltage depends primarily on scintillator efficiency and should be calibrated using a radiation source.

Since the spectral response range of silicon photodiodes includes the visible light region, care must be taken to avoid exposing the photodiode to high ambient light levels, especially light from tungsten sources or sunlight. During transport, photodiodes are packaged in opaque, padded containers to protect against ambient light exposure and damage from drops or vibration.

Photodiodes may fail if dropped or subjected to severe shock. Bonding wires are extremely fine and may become detached.

Features

• Large photosensitive area
• Fully depletable
• Fast response
• Ultra-low dark current
• Low capacitance
• Scintillator-mountable
• High breakdown voltage

Applications

• Electronic inspection
• Medical instrumentation
• High-energy spectroscopy
• Charged particle detection
• High-energy physics
• Nuclear physics
• Control systems