GammaLab 0.4.1

Toolkit for soundcard gamma ray spectroscopy

Python toolkit for soundcard gamma spectroscopy.

Spectrum of Am-241 acquired with a CsI(Tl) scintillation detector and Gamma Lab

Introduction

This package is a Python package for the acquisition and analysis of soundcard data, specifically for gamma spectroscopy kits that use a soundcard as their ADC interface. It consists of independent building blocks (“services”) that can be connected and reconfigured to form different analysis pipelines. Examples of this are included in the repository in the examples directory.

Prerequisites

You need at least:

• Python 2.7 or 3.6 or later,

• numpy

• the Python sound interface SoundCard

and recommended is:

• matplotlib

Installation

Easiest is to use pip:

pip install GammaLab

Usage

An example application that acquires data and plots a gamma spectrum is included, you can get help:

> gammalab-histogram.py --help

This provides only a limited preview of the possibilities that the Gamma Lab offers. You can compose your own applications, examples of this are in the examples directory.

More details

The applications consist of components “services” that are connected with “wires.” For a component to be included it needs to be imported and instantiated, for example you almost always need:

from gammalab.acquisition import Soundcard
soundcard=Soundcard()

After instantiating additional components, say:

from gammalab.backend import SaveRaw
save=SaveRaw()

they need to be “wired”:

soundcard.plugs_into(save)

At the moment, components can have one input and one output, but an output can be connected to multiple components. When all components are wired, you start the pipeline:

main(timout=100)

The time-out is optional. The application will run until <enter> is pressed or until the time-out reached.

The following services are available:

from gammalab.acquisition import SoundCard
from gammalab.acquisition import Noise
from gammalab.transform import Raw2Float
from gammalab.transform import DownSampleMaxed
from gammalab.transform import Identity
from gammalab.analysis import PulseDetection
from gammalab.analysis import Histogram
from gammalab.analysis import Count
from gammalab.backend import PyAudioPlay
from gammalab.backend import Monitor
from gammalab.backend import SaveRaw

Note that most of these provide rudementary implementations and are open to improvement.

Development

It is not difficult to program additional services.

A service is a class with at least the methods: start stop and close. A service which accepts input should instantiate a “wire” class defining its input and have connect_input and receive_input methods (normally taken care of by deriving from ReceivingService class). If it generates output, the service should have an output_protocol method, which checks the input wire format and propagates any additional information to the wire. It also needs to have some methods normally implemented by deriving from the SourceService class (notably the `plugs_into` method).

Services start up a seperate thread to do their computations. This could also be using some other package’s thread (e.g. for soundcard acquisition pyaudio’s callback thread is used).

The simplest example of a service with input and output is the following:

class Identity(ThreadService, SourceService, ReceivingService):
    def __init__(self):
       super(Identity, self).__init__()
       self.input_wire=RawWire()

   def output_protocol(self, wire):
       assert isinstance(wire, RawWire)
       wire.CHANNELS=self.input_wire.CHANNELS
       wire.RATE=self.input_wire.RATE
       wire.FORMAT=self.input_wire.FORMAT

    def process(self, data):
       return data

This service just forwards the input data (a raw byte stream) to its output, retaining its sample rate, format and number of channels.In this case the necessary start etc methods are provided by inheritance from ThreadService.