Monday, April 14, 2014

Digital Neutron-Gamma discrimination with Liquid Scintillators

In recent years CAEN has developed a complete family of digitizers that consists of several models differing in sampling frequency, resolution, form factor and other features. Besides the use of the digitizers as waveform recorders (oscilloscope mode), CAEN offers the possibility to upload special versions of the FPGA firmware that implement algorithms for the Digital Pulse Processing (DPP); when the digitizer runs in DPP mode, it becomes a new instrument that represents a complete digital replacement of most traditional modules such as Multi-Channel Analyzers (MCAs), QDCs, TDCs, Discriminators and many others. In this application note, CAEN describes the capability of the series x720 (12 bit, 250MSps) to perform neutron-gamma discrimination based upon the digital pulse shape analysis. The development of this FPGA firmware was based upon liquid scintillating detectors of type BC501-A.
 
All detector and neutron/gamma source based tests were performed at the Triangle Universities Nuclear Laboratory (TUNL) on the campus of the Duke University in collaboration with Prof. Mohammad W. Ahmed.

Thursday, April 3, 2014

About Ruthenium Oxide Temperature Sensors

Ruthenium Oxide Temperature Sensors are thick film resistors which are interchangeable and usable in large magnetic fields with excellent accuracy without special calibration. These sensors are available as uncalibrated, grouped, or calibrated (Fig. 1) units at reasonable cost.

FEATURES:
Excellent Magnetic Field Performance
Interchangeability
Repeatability
Fast Thermal Response
Rugged
Temperature Range: .05°K to 20°K. Custom ranges available, contact X-TRONIX.

PHYSICAL SPECIFICATIONS:
Gold plated OFHC copper enclosure, Dia . . 093" (2.4mm) x Length .200" (5. lmm)
Phosphor-bronze lead wire-standard, 4-Leaded, Polyimide coated, 36 AWG, Custom leads available
 

Friday, March 21, 2014

Next Generation Crystal Microbalances for Thin Film Deposition Monitoring & Control

by Scott Grimshaw, Colnatec USA

The "Achilles heel" of thin film deposition process monitoring and control is the quartz crystal microbalance (QCM). Since its advent in the 1960's, QCM's have been an integral part of most commercial thin film coating systems. Unfortunately, the limitations of QCM's for processes such as optical coating, ion beam sputtering, MBE and CVD have not been adequately addressed.
 
A new class of QCM sensor, designed for elevated temperatures, high stress dielectrics and extremely thin coatings is now available. This new sensor embodies an advanced crystallographic cut, "smart" sensor housings with integrated heaters, and novel crystal materials to extend the range of thin film monitoring to up to 250°C. 

INTRODUCTION
Quartz crystal microbalances operate in a relatively simple fashion. The QCM consists of a disc of quartz cut at a specific angle and shape from a bar of synthetically grown quartz. This quartz disc is then coupled into an electrical circuit and caused to vibrate at its natural resonance frequency. The resonance changes (decreases in frequency) whenever a thin film coating collects on the crystal surface. If the density of the film material is known, an algorithm can be used to compute the film thickness. 

Sunday, March 9, 2014

13th Int. Conference on Muon Spin Rotation, Relaxation & Resonance

June 1-6, 2014. The 13th International Conference on Muon Spin Rotation, Relaxation and Resonance (μSR2014) is to be held in Grindelwald, Switzerland, from Sunday, June 1st to Friday, June 6th, 2014. It is organized by the Paul Scherrer Institut (PSI), the University of Zurich and the University of Fribourg.
 
The conference provides a forum to researchers from around the world with interests in the applications of μSR to study a wide range of topics including condensed matter physics, materials and molecular sciences, chemistry and biology. The Conference will consist of invited and contributed talks as well as poster sessions.
 

Wednesday, January 29, 2014

Wafer-scale design of lightweight and transparent electronics that wraps around hairs

ETH Zürich contributors: Giovanni A. Salvatore, Niko Münzenrieder, Thomas Kinkeldei, Luisa Petti, Christoph Zysset, Ivo Strebel, Lars Büthe & Gerhard Tröster
A new way of making ultra thin, flexible and transparent electronics has been unveiled by researchers in Switzerland. The technique involves fabricating micron-thick electronic devices on a conventional silicon wafer, which is later detached by soaking it in water. The free-floating devices can then be placed onto a variety of biological tissues, including human skin and even a single hair. The technology could be used to make "smart" contact lenses for monitoring the pressure in an eyeball or for creating flexible solar cells.

Energy Resolution & Linearity of the CAEN MCA DT5780

The Digital Multi Channel Analyzer DT5780 represents the synthesis of CAEN's long lasting experience in high voltage power supplies and in digital acquisition systems. The device houses two HV channels with ±5 kV maximum voltage and two 14 bit acquisition channels with 100 MS/s sampling rate. The device allows through its internal logic to require coincidences and anti‐coincidences between events triggered by the two acquisition channels.

In the present Application Note we report the results obtained in internal tests of the Digital Multi Channel Analyzer DT5780. We are going to show the resolution of the energy measurement of gamma and X rays obtained with a HPGe detector. The wide spectrum of energy available allows also to obtain a preliminary test of the linearity of our MCA. We want underline that this test is preliminary and does not take into account the nonlinearity of the HPGe detector and the preamplifier, and possible dependencies on the event acquisition rate.

Click to download application note PDF

Click for technical details on DT5780
 

Tuesday, January 14, 2014

Powerful Solution for the Emulation of Any Detection Setup

The Digital Detector Emulator is a multichannel instrument for the emulation of radiation detection systems. The algorithm is initialized by a reference pulse shape, with statistical distribution of amplitude and time. Then a statistical stream of events is generated according to the input distributions. The events can be also selectively summed together simulating the pile-up phenomenon. An arbitrarily generated noise and a baseline drift can be superimposed to each pulse.

Therefore, the instrument is not a pulse generator of recorded shapes, but it is a synthesizer of random pulses compliant with programmable statistical distributions of energy spectrum, time distribution, and pulse shape. The stream of emulated signals becomes a statistical sequence of pulses, reflecting the programmed input features (e.g. energy spectrum, time distribution, noise, signal shape, etc.). When the emulation process is reset, the kernels of generators can be either re-initialized with new random data making the sequence always different, or they can be stored to reproduce the same sequence many times.

Wednesday, January 8, 2014

Krytox® PFPE in Vacuum Applications

Krytox® performance lubricants are the products of choice for applications where complete nonflammability, oxygen compatibility, and resistance to aggressive chemicals are requirements. These synthetic lubricants provide superior performance and extended life as lubricants and sealants.

xtronix caters to a variety of vacuum and non-vacuum applications with different grades of Krytox® oils and greases. We have addressed aerospace related markets, high voltage industrial applications, paper mills, tribology applications in clean room environments, and many others.

An important area of use for Krytox® relates to vacuum-based applications:
• Vacuum pumps, where safety is critical
• Hostile environments, where semiconductor process chemicals can attack most other lubricants
• Vacuum system valves, seals, bearings and connectors, where low vapor pressure, outgassing, and contamination are intolerable

Thursday, November 21, 2013

Tips & Tricks - Vacuum Viewports

This had already been posted back in September 2007 on our old blog and as it had attracted tremendous interest I'm happy to give it a makeover with more detail !

For those who do not often change things on a UHV vacuum system, here's some tips if you need to mount a viewport. First, never use a viewport that appears to be, or is known to be damaged. A replacement viewport costs far less than repairing a system that has been subject of an implosion caused by a faulty viewport.

SAFETY
Pressure differentials: Kodial VPZ viewports are designed to withstand 1 Bar differential pressure. Other standard viewports are designed to withstand 2 Bar differential pressure. The pressure on the ‘vacuum side’ of the viewport must not exceed a positive pressure differential of 1 bar. The viewports are designed for vacuum applications.
  • WARNING: Pressures in excess of this or high reverse pressures may cause catastrophic failure and result in serious injury.


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