Experimental Nuclear Physics Laboratory,University of Liège, Belgium

The GesSpectre Program & Applet

A new multiplatform version of the program is under development (compatible with Windows, OS X and Linux) : see http://www.ipnas.org/garnir/javaspectre

The GesSpectre program (Macintosh only!)

GesSpectre visualizes and analyzes spectra obtained from nuclear particle detectors. It emulates the display of a multichannel analyser (MCA). The acquisition is made by an external ADC connected to the Macintosh through a serial RS422 line or with a direct connection to an ADC via a PIA interface. Data can also be read from text files. It is specially oriented to PIXE (Particle Induced X-ray Emission) spectra.

Main characteristics

• Up to 9 spectra may be viewed independently and simultaneously in windows.
• Each window has all the Mac usual controls (elevators, grow box, zoom box, etc.).
• The start and stop of an acquisition are controlled by the program and the spectra accumulated in an external device are quickly transferred to memory. Direct connection to an ADC is supported with real time display. All activities are available during acquisitions.
• Each spectrum can be saved in fast compact binary format or as text file.
• Parametric calibration (2nd order) is calculated individually for each spectra.
• Regions of interest (R.O.I.) may be defined anywhere in the spectrum (using only the mouse) and their characteristics instantly presented on the screen. (With a B/W monitor the R.O.I. are presented in bold.)
• On request, the characteristics of the R.O.I. (position, surface, background etc.) are accumulated under a table format, which may be printed, saved on disk (as a "tab separated text file") or directly transferred into the clipboard (under an Excel™ compatible format).
• The spectrum graphic image may be copied into the clipboard (to be printed or included in a report)
• Automatic processing may be done by creating a "Macro" (a list of commands that could be replayed automatically) and, with the adequate hardware, a sample changer may be controlled.
• The program works only with System 7 (or up) and fully conforms to the Macintosh interface. It is written in Think Pascal™ (V4.02) and occupies about 250 kbytes. Pascal sources may be obtained on request.
• It contains a WWW that allows remode control of the program through the Internet.

The GesSpectre Applet (all browsers)

The GesSpectre applet is written in the JAVA language and offers to the user a control panel which displays the spectra in real time. The spectrum appears in a window surrounded by different buttons controlling the remote MCA. We have tested the Applet with Netscape and Internet Explorer running on different operating systems.

This applet has to connect to a Macintosh computer connected to the Internet and running GesSpectre with the menu item "Gadget/TCP server "activated.We try to keep two Mac running GesSpectre : ulcn5.pne.ulg.ac.be and sopra2.pne.ulg.ac.be (Caution: these computers are not always on!)

The applet will try to connect itself to a that computer, if you get a "security violation" error you should check your browser security options. It's possible to configure IE but not Netscape. Some help (in french) with that.

To load and try the Applet call :GesSpectre Applet (from a local LC - OK for Netscape - but not always on!)

Dowload the The GesSpectre kit (500 k self extracting archive with the program , server & applet)

Help, manual and sources files

• the "readme" .pdf file describing the main options of GesSpectre (3 pages in english)
• the" manuel " of GesSpectre in French! (fichier .pdf de 25 pages)
• The Source files (in Think Pascal and CodeWarior JAVA)

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Publications related to nMCA GesSpectre

• SBP99
• icalep99

How to activate it?

The GesSpectre server works on port 5521, to make it actif, the option "TCP server" of the menu "Gadget" must be activated after each start.

How to read a remote spectrum directly from a browser?
To read a spectrum from a browser, use the following URL:
http://<machine name>:5521/data (version binaire)
http://<machine name>:5521/dataT (version textuelle)
Ex: http://sopra2.pne.ulg.ac.be:5521/dataT

What kind of data are transfered?
The text version is formed by the canal content values on successive lines (could be read by any program accepting textual input).The binary version is compatible with GesSpectre binary data format.

The MIME signature of the files are:

spectre/octet-stream (binary)
spectreT/octet-stream (text)

On a Macintosh, the files could be signed to automaticaly open GesSpectre:

Creator : IPN1
Type : SPEC (binaire) or TEXT (texte)

What commands are available?
GesSpectre reacts by detecting in the first line of the Internet calling message some words (cf. function POS() of Pascal). To call a function, you have to use a "fake" URL formed as follow : http://<machine name>:5521/< word(s)>

The actif words are:

• HTTP uses the WWW format in the answers (puts a header with the minimum info needed by the browsers : HTML Version 1 et le code MIME). Without the HTTP word, the answers do not contain a header but only the data.
• data the data received contains a binary bloc of (nb. canaux x 4 octets) lengths.
• dataT you will receive a text with [nb. canaux] lines containing an ASCII numerical value on each line (the lines are terminated by <CR><LF> cf . DOS)
• start starts the remote acquisition (the answer is the status before the action)
• stop stops the remote acquisition (the answer is the status before the action)
• clear clears the remote spectra (the answer is the status before the action)
• calib gives three numbers ( a,b, c) of the parabolic calibration curve (a x^2+b x +c) and the X axis unit of the axes (followed by the status)
• status requests the status. The answer is like : 104 what: OPEN 1024 T= 7 sec ACQ
  OPEN : at least one spectra window is open in the remote gespectre ; 1024 is the size in channels ; T = 7 sec. : duration of the acquisition since it starts or since the last clear ; ACQ : An acquision is running
• info : sends a text file with info/help (the file index.html near to GesSpectre)

Ex: To get the status : http://sopra2.pne.ulg.ac.be:5521/status

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H.P. Garnir , P.H. Lefebvre, M. Clar, F. Monjoie August 99