Photomultiplier Tube Technology Research Articles

Spectroradiometry with sub-microsecond time resolution using multianode photomultiplier tube assemblies.

Accurate and precise measurements of spectroradiometric temperature are crucial for many high pressure experiments that use diamond anvil cells or shock waves. In experiments with sub-millisecond timescales, specialized detectors such as streak cameras or photomultiplier tubes are required to measure temperature. High accuracy and precision are difficult to attain, especially at temperatures below 3000K. Here, we present a new spectroradiometry system based on multianode photomultiplier tube technology and passive readout circuitry that yields a 0.24 µs rise-time for each channel. Temperature is measured using five color spectroradiometry. During high pressure pulsed Joule heating experiments in a diamond anvil cell, we document measurement precision to be ±30 K at temperatures as low as 2000K during single-shot heating experiments with 0.6 µs time-resolution. Ambient pressure melting tests using pulsed Joule heating indicate that the accuracy is ±80 K in the temperature range 1800-2700K.

Lightwave‐Driven Long‐Wavelength Photomultipliers

AbstractA novel lightwave‐driven detector that combines photomultiplier tube (PMT) technology with structured metasurfaces is presented to enable efficient detection of long‐wavelength radiation in the mid‐infrared (mid‐IR) to terahertz (THz) range. This overcomes the limitations of conventional PMT technology, which cannot efficiently detect wavelengths longer than 1.7 m. The approach utilizes the long‐wavelength radiation's instantaneous electric field to facilitate field‐driven electron emission from metasurfaces, which allows it to cover the entire THz to mid‐IR range by geometric scaling. This enables a novel class of lightwave‐driven detectors with the benefits and performance characteristics known from the established PMT technology, such as fast response times and low noise, while expanding the operational wavelength range vastly. It is shown that the amount of field‐emitted electrons depends on the THz electric field in a highly nonlinear manner, generally following the Fowler–Nordheim relation. Furthermore, the THz‐PMT can determine specific lightwave characteristics of the incident field, including its peak field strength and absolute polarity, due to its sensitivity to the sign of the electric field. With a field sensitivity as low as a few kV cm−1, the THz‐PMTs provide a versatile tool for high sensitivity detection across various fields of interest in science and technology.

Pulse dilation gas Cherenkov detector for ultra-fast gamma reaction history at the NIF (invited).

The Cherenkov mechanism used in Gas Cherenkov Detectors (GCDs) is exceptionally fast. However, the temporal resolution of GCDs, such as the Gamma Reaction History diagnostic at the National Ignition Facility (NIF), has been limited by the current state-of-the-art photomultiplier tube technology to ∼100 ps. The soon-to-be deployed Pulse Dilation Photomultiplier Tube (PD-PMT) at NIF will allow for temporal resolution comparable to that of the gas cell or ∼10 ps. Enhanced resolution will contribute to the quest for ignition in a crucial way through precision measurements of reaction history and ablator areal density (ρR) history, leading to better constrained models. Features such as onset of alpha heating, shock reverberations, and burn truncation due to dynamically evolving failure modes may become visible for the first time. Test measurements of the PD-PMT at Atomic Weapons Establishment confirmed that design goals have been met. The PD-PMT provides dilation factors of 2 to 40× in 6 increments. The GCD-3 recently deployed at the NIF has been modified for coupling to a PD-PMT and will soon be making ultrafast measurements.

Modeling Photo-multiplier Gain and Regenerating Pulse Height Data for Application Development

Systems that adopt organic scintillation detector arrays often require a calibration process prior to the intended measurement campaign to correct for significant performance variances between detectors within the array. These differences exist because of low tolerances associated with photo-multiplier tube technology and environmental influences. Differences in detector response can be corrected for by adjusting the supplied photo-multiplier tube voltage to control its gain and the effect that this has on the pulse height spectra from a gamma-only calibration source with a defined photo-peak. Automated methods that analyze these spectra and adjust the photo-multiplier tube bias accordingly are emerging for hardware that integrate acquisition electronics and high voltage control. However, development of such algorithms require access to the hardware, multiple detectors and calibration source for prolonged periods, all with associated constraints and risks. In this work, we report on a software function and related models developed to rescale and regenerate pulse height data acquired from a single scintillation detector. Such a function could be used to generate significant and varied pulse height data that can be used to integration-test algorithms that are capable of automatically response matching multiple detectors using pulse height spectra analysis. Furthermore, a function of this sort removes the dependence on multiple detectors, digital analyzers and calibration source. Results show a good match between the real and regenerated pulse height data. The function has also been used successfully to develop auto-calibration algorithms.

The use of silicon photomultipliers for very high energy gamma ray astronomy: the optical issues

Due to its sensitivity and speed, the detector still widely used in Cerenkov astrophysics experiments remains the Photo-Multiplier Tube (PMT). However, there are some disadvantages to the PMT technology: the rather poor quantum efficiency, the use of high voltages, the high cost when used in large number in a matrix arrangement and a subsequent large weight. Hence, we have investigated the possibility to design future Cerenkov telescope cameras based on solid state technology, specifically Geiger Avalanche PhotoDiodes (G-APD’s). This paper describes our extensive simulations to design the optical setup to be employed with G-APD’s. We also discuss the reflector configurations, pixel layouts, light concentrators, microlens arrays and spectral efficiencies to optimize light collection. The electronic aspects of our work were presented in a recent companion paper (Pellion et al., Exp. Astron. 27(3):187, 2010).

Geiger avalanche photodiodes as tentative light detectors for VHE gamma ray astronomy

Due to its sensitivity and speed, the detector still widely used in Cerenkov astrophysics experiments remains the PhotoMultiplier Tube (PMT). For instance, recent pathbreaking experiments in Very High Energy astrophysics (VHE), such as MAGIC and HESS, have used mainstream PMT technology (Aharonian et al, Astron Astrophys 492(1):L25-L28, 2008). Moreover the Cerenkov Telescope Array (CTA) which is now in its design phase, is also planed to be based on PMT's. However, there are some disadvantages to the PMT technology: the rather poor quantum efficiency, the use of high voltages, the high cost when used in large number in a matrix arrangement and the large weight. Hence, we have investigated the possibility to design future Cerenkov telescopes based on solid state technology, specifically Geiger avalanche photodiodes. In a preliminary development

Photodetectors for the CMS hadron calorimeters

Hadronic energy measurements in the central and end cap regions of the Compact Muon Solenoid (CMS) detector will be made using sampling calorimeter techniques with plastic scintillator tiles as the sensitive layers. Plastic fibers doped with wavelength shifting fluors embedded in each tile are used to extract the scintillation light. Clear plastic wave guide fibers carry the shifted light to photodetectors located on the outer surface of the calorimeter structure. Environmental constraints and physics performance requirements for these photodetectors are presented. Candidate photodetector technologies are discussed, and the hybrid photomultiplier tube technology is identified as most promising.

Photon correlation study of stellar scintillation

DURING the past decade photomultiplier-tube technology and signal processing using integrated circuits have progressed to the point at which the analysis of fluctuating light signals can now be carried out digitally, in real time, with accuracy close to the theoretical limit. These ‘photon correlation’ techniques have so far found their main application in laser light-scattering spectroscopy1 and laser doppler velocimetry2. The techniques need not, however, be limited to applications involving lasers and can be used for the analysis of fluctuating optical signals of any origin (provided the fluctuation time is ≥ 10−8 s). Here we report a preliminary study of the statistical and temporal correlation properties of stellar scintillation, taking advantage of the fast response time and high sensitivity of equipment now standard for laser light-scattering applications.