Characteristics of plastic scintillator

Plastic scintillators belong to organic scintillators, but not organic crystal scintillators. It can be used for the detection of alpha, beta, gamma, fast neutrons, protons, cosmic rays and fission fragments. It is easy to transparent body into very large, easy processing into various shapes, with no deliquescence, stable performance, radiation resistance, short decay time and flashing advantages of low price, is a kind of scintillator is widely used today.

Characteristic
A, simple in production, low in price, easy to process into various shapes, such as column, piece, ring, rectangle, well shape, tube, film, filaments, particles and so on.

B, high transparency, good light transmission performance, can be made into large volume scintillator.

C, scintillation attenuation time is short, suitable for nanosecond time measurement and high intensity radiation measurement.

D, stable performance, high mechanical strength, vibration resistance, impact resistance, moisture resistance, no need for encapsulation, light saving 8~10a luminescence efficiency has no obvious change.

E, radiation resistance in various scintillator first, can be used for high radiation field emission, high exposure rate.

F, softening temperature is low, can not be used under high temperature conditions.

G, soluble in aromatic ketones and solvent, ethanol, dilute acid, dilute alkali and very little impact on it.

H, poor energy resolution, generally only for strength measurement

Optical and Laser Components

Optical and Laser Components

1. Flowtubes, Monoblocks and Specular Reflectors for Lamp- and Diode-based Pump Chambers.

Flowtubes and Monoblocks are an essential component of the flashlamp-pumped pump chambers; they carry out the following functions:

– Provide flow-channel for cooling liquid;

– Absorb (filter-out) undesired UV-radiation, reducing heat load, thermal lensing effect and protesting the active medium from long-term solarization;

– Provide internal support for BaSO4 reflectors;

– Blocking lateral stimulated emission, which can depopulate the laser rod and significantly reduce amount of the extracted energy in Q-switched mode. For the Q-switched Nd:YAG Laser Samarium-doped Glass is the material of choice, because it attenuates lateral depumping effects, thus avoiding super luminescence phenomena and absorbing undesired UV radiation.

Cerium Glass and Europium Quartz Glass are also interesting doping materials, because they absorb undesired UV-radiation and can additionally re-emit this energy in the useful spectral range. For free-running lasers, Duran and Quartz Glass are the materials of choice for fabricating the flowtubes, while undoped-YAG and Sapphire can also be used when harsh conditions warrant.

Flowtubes and monoblocks are machined out of a block of glass with highly polished interior and exterior surfaces. The channels containing the laser rod and flashlamps are deep-bored with tight control of dimensions and tolerances on parallelism and perpendicularity. In case of Sm- or Eu-doped glass, the monoblocks are subjected to ion-exchange strengthening in accordance with instructions of glass manufacturer.

All shapes and configurations of monoblocks are available including multi-channel cylindrical, ellipsoid, shotgun, etc. sections with flat or indented end-surfaces for reliable sealing. Please contact us with your specific requirements.

The monoblocks can be used as part of diffuse pump chambers with BaSO4 reflectors. In addition, the polished exterior cylindrical or elliptical surfaces can be coated with Cu/Ni-protected Silver or Gold coating to form the high efficiency Specular Reflector, with some standard configurations available on a short notice.

Presence of strong thermo-optical effects in high power diode pumped lasers presents a challenge in obtaining high output power with low-order modes. In various Nd:YAG laser configurations like rod, slab or disk lasers thermally-induced refractive index changes lead to lensing, aberrations and birefringence. For power scaling of diode pumped solid state lasers the uniform pumping configuration and effective thermal management are required.

For better pumping and cooling management of diode-pumped solid-state lasers, our preferred vendor has developed a range of state of the art Sapphire and Fused Silica reflector flowtubes for axial uniform pumping. The barrel surface of flowtubes is coated by Cu/Ni-protected, highly reflective Gold layer. For uniform distribution of laser diodes pumping radiation within laser rod, multiple configurations of flowtubes have been developed. Due to high manufacturing precision combined with innovative know-how, these reflectors demonstrated reduced thermally-induced effects of lensing and aberration, and improved output power and optical-to-optical efficiency of the laser.

IR Lenses-Thermal Imaging Cameras

IR Lenses are used to collect, focus, or collimate light in the near-infrared, short-wave infrared, mid-wave infrared, or long-wave infrared spectra. IR Lenses are optical lenses that use specific substrates or anti-reflection coatings to maximize performance for applications operating above 700nm including thermal imaging, FLIR, or spectroscopy. The infrared spectrum refers to 700 – 16000nm wavelengths. When divided into smaller spectra, NIR refers to 700 – 900nm, SWIR is 900 – 2300nm, MWIR is 3000 – 5000nm, and LWIR includes 8000 – 12000nm wavelengths.

Edmund Optics offers a large variety of IR Lenses including singlet lenses, achromatic lenses, aspheric lenses, or focusing objectives for high performance across a large portion of the infrared spectrum. IR Achromatic Lenses are ideal for use in a variety of industrial, life sciences, or defense applications including FTIR spectroscopy or for use with tunable QCL lasers. Zinc Selenide IR Aspheric Lenses feature diffraction limited designs that are ideal for focusing the output of CO2 lasers. Additional substrates include germanium, sapphire, silicon, zinc selenide, or zinc sulfide. Anti-reflection coating options include VIS-NIR, NIR I, NIR II, Telecom-NIR, or SWIR.

Thermal Imaging-IR Lenses

A pockels cell with a broken crystal

In a 2P microscope, pockels cells are employed for fast control of the laser beam intensity. I use it for both switching off the laser beam during turnarounds of the resonant scanner, between two frames if they are not immediately one after the other, and to adjust the beam intensity when scanning in z for multi-plane imaging. In total, the pockels cell is quite essential for me. Alternatively, people use mechanical shields to blank the beam during the turnaround, or slow motorized rotating λ/2-plates to adjust the laser intensity on a timescale of seconds.

Recently, I found out how a defect pockels cell can look like. For comparison, the first video shows a properly working pockels cell, although the refractive index-matching liquid inside might be a little bit low. The air-liquid interface can be clearly seen at some points.

In the second video, the crystal inside the pockels cell is clearly broken and therefore visible. This could be clearly seen immediately when looking at the laser beam, which was strongly diffracted after passing the pockels cell.

This defect occured most likely when the cell driver remained switched on for an extended period of time, with the offset voltage being set to a rather high value. So this happened due to the permanent voltage applied to the crystal, and not due to the pulsed laser intensity.

This article comes from ptrrupprecht edit released

Definition of Organic Scintillators

The scintillation in organic scintillators is due to the transitions between energy levels in a single molecule. These scintillators avoid the need for a regular crystal lattice structure. In organic scintillator molecules, the energy spacing the vibrational modes is 0.15eV and between the levels S0 and S1 is 3eV. Excitation of molecule from the ground state to the higher states occurs when energy is stored in the scintillator by a charged particle. Phosphorescence is emitted when the molecule is transferred from the S1 state to the T1 state.

A bulk solvent is added to the organic scintillant at small concentrations and the mixture is exposed to ionizing radiation. Light is emitted when the energy absorbed by the solvent is transferred to the scintillant.

Liquid scintillation counting is one of the challenging applications of organic scintillators in the field of nuclear medicine. In this technique, the scintillator used is a liquid dissolved with the radioactive sample to be assayed. The activity of low energy β-emitting radionuclides like 14C and 3H can be measured using this method.

This article comes from azosensors edit released

Nonlinear crystal phase matching

We offer a wide selection of nonlinear crystal phase matching. Various nonlinear crystal phase matching including Lithium Triborate (LBO), Beta Barium Borate (BBO), Potassium Titanyl Phosphate (KTP), Potassium Dihydrogen Phosphate & Potassium Dideuterium Phosphate (KDP & DKDP), Lithium Iodate (LiIO3), Lithium Niobate (LiNbO3) and infrared nonlinear crystal phase matching (AgGaS2, AgGaSe2, GaSe, ZnGeP2) with given standard sizes and orientations are available for fast off-the-shelf delivery.

However inquiries for custom made nonlinear optical crystal are also welcome. Nonlinear crystal phase matching are used in wide range of optical frequency conversion applications including laser harmonic generations (SHG, THG, 4HG), sum or difference frequency generation (SFG, DFG) and optical parametric generation, amplification or oscillation (OPG, OPA, OPO). Some nonlinear crystals for instance DKDP, BBO and KTP also possess electro-optical properties which make them useful for electro-optical applications – Q-switching or electro-optical amplitude modulation.

This article comes from eksmaoptics edit released

New generation of organic scintillation materials

We have designed and produced the next generation of organic scintillation materials.

The are organic polycrystals obtained from finely ground perfect single crystal by the pressing technology and organic composite scintillators obtained by introduction of crystalline grains into an optically transparent polymer base. The scintillation characteristics of proposed scintil-lation materials as detectors for short-range ionizing radiation and fast neutrons are discussed.

This technology is the base for production large area detectors which can be used in facilities for environmental radiation control, for security purposes (i.e. to prevent the forbidden entry of fission materials), for physical experiments, and in other branches of science and technol-ogy.

This article comes from researchgate edit released

Synthesis, Crystal Structure and Nonlinear Optical Crystals Property of RbHgI3

Searching for new nonlinear optical crystals to be used in the infrared (IR) region is still a challenge. This paper presents the synthesis, crystal structure and properties of a new halide, RbHgI3.

Its non-centrosymmetric single crystal can be grown in solution. In its crystal structure, all the polar [HgI4]2− groups align in such a way that brings a favorable net polarization. The measurement by Kurtz–Perry powder technique indicates that RbHgI3 shows a phase-matchable second harmonic generation (SHG) property seven times stronger than that of KH2PO4 (KDP).

RbHgI3 displays excellent transparency in the range of 0.48–25 μm with relatively good thermal stability. The UV absorption implies that this yellow compound’s band gap is about 2.56 eV, close to that of AgGaS2. A preliminary measurement indicates that the laser-induced damage threshold of the crystal is about 28.3 MW/cm2.

These preliminary experimental data reveal that RbHgI3 is a new candidate as nonlinear optical material in the infrared region.

This article comes from mdpi edit released

Gallium Arsenide Lenses

GaAs lenses is semi insulator, which can be used in large power continuous CO2 laser system to replace the zinc sulfide in lens or mirror forms. GaAs lenses is suitable in applications consists of toughness and durability.

In some cases, particles of dust or steel will impact the optical element surface, the hardness and strength of GaAs lenses surface makes it a good choice under such circumstance.

GaAs lenses was originally intended for use in semiconductor applications (rather than optical applications), and therefore, it is extremely important to make careful screening of materials in the manufacture of high quality GaAs lenses optical components.

GaAs lenses optical elements are subject to the restriction of crystal growth technology, the diameter is generally below 10 cm. The materials are hygroscopic and can be safely used in laboratory and field application, its chemical properties are very stable (except contact with strong acids)

When handling optics, one should always wear gloves. This is especially true when working with Gallium arsenide components, as it is a hazardous material. For your safety, please follow all proper precautions, including wearing gloves when handling these lenses and thoroughly washing your hands afterward.

This article comes from hypoptics edit released

The Leader in Optical Filter Solutions

We develop thin film optical filters and coated components for a wide variety of applications including telecommunications, spectroscopy, consumer optics, space, satellite, and astronomy. Filter types include band-pass, edge-pass, AR, anti-smudge, multiband, and other optical filters from 300nm to 10um.

This article comes from photonics edit released