Previous Page
41 CRIB Optimizer
  • 29 Jul 2010 19:50:25

Introduction

CRIB Optimizer is a very useful program often used at the CRIB facility. It was written by Dr. J. J. He while he was working at the Center for Nuclear Study.

As far as I know, the program is written in MS Visual Basic, and it can only be run on an MS Windows system; I never found a method for running it on another platform (e.g. with wine).

The program can help facility users during radioactive beam development, for example by assisting to determine Bρ settings for the system, producing particle identification plots, and so on.

My main goal here is to explain how to install the program and host the code for collaborators. I had no part in the coding of this software or its development, but I did have some trouble getting it installed on my system, so I'm just going to tell you the steps I took to make it work on my laptop.

Download the code

The most recent version of the code I have is from November 2005: nov14_2005.zip

You will also need an older version of the PPAC energy loss for functionality: EPPACLoss_2004.zip

Finally, you will need to install a version of GSView. I have successfully used up to v4.9

Installing the software

(I assume you can handle zip files; otherwise, try the most recent version of WinZip, or perhaps an old version.)

Extract the zip file nov14_2005.zip in some temporary location, and enter the folder for nov14_2005\packages\

Double click the file setup.exe

If you do not have Chinese (or related) font support on your machine, then next you will need to click on the button which is labelled "??"

Warning: DO NOT CHANGE THE INSTALL DIRECTORY. MUST BE INSTALLED AT C:\CRIB_Opt

Next, click the upper left button with a computer icon, and the program will install.

Once it is installed, unzip the contents of EPPACLoss_2004.zip into C:\CRIB_Opt\ and overwrite the two files.

Next, make sure you already installed GSView as per the official website. Once GSView is installed, go to C:\Program Files\Ghostgum\gsview\ and copy the program gsview32.exe, which would be called gsview64.exe for 64-bit architectures. Paste this into C:\CRIB_Opt\ to overwrite existing version (or for 64-bit, paste it and rename it to gsview32.exe, which CRIB Optimizer is expecting).

Now CRIB_Opt will be fully functional! Just double-click the CRIB_Opt.exe within C:\CRIB_Opt\ folder, or make shortcuts as you like.

Words of warning for 2H2 and 3He production targets

CRIB Optimizer is using parts of the enewz code for energy loss. This code uses the abundant isotopes of hydrogen and helium for energy loss calculations, because that data is readily available. This is incorrect for different isotopes of hydrogen and helium! In principle the SNKE_MATTER.DAT has been modified for the 'HE3' and 'D2' masses, but I think it needs some debugging and further consideration. You can modify the file by hand and see what kind of results you can get. It is also difficult to know since sometimes the cryogenic target builds up ice which alters the effective target thickness. If you notice some inconsitencies, I list some suggestions you may try without altering the code yourself. In the best case, you can consider a range of CRIB experimental data, figure out if there is any problem with SNKE_MATTER.DAT, and send me the updated file so I don't have to do it later myself.

The problem is that energy loss is caused by electrons, but yet target thicknesses are calculated based on mass, which comes mainly from atomic nuclei.

The solution is simple: multiply your experimental target thickness by a mass-modifier for the input to CRIB Optimizer.

For 2H2, the mass is roughly twice that of ordinary hydrogen, so you should input a target thickness that is one-half your actual target thickness.

For 3He, the mass is less than the alpha particle, so multiply the actual target thickness by 4/3.

I hope if you think about the physics, you will be convinced this modification makes some sense. We have experimentally confirmed it some time ago for the case of 3He(28Si,30S)n in December 2006 at CRIB.

2 PPAC energy loss changes

Since the time the CRIB Optimizer program hosted here was created, the F3 PPACs now have thinner windows than the F2 PPAC (previously they were all identical). Thus energy loss using 2 PPACs will overestimate the energy loss in the code compared to experimental data collected at F3. If you use enewz yourself, you can estimate the differences to compare with the plots generated by the CRIB Optimizer.

For the F2 PPAC, it was found that its energy loss can be approximated as 13.78 μm of mylar.

For one F3 PPAC, it was found that its energy loss can be approximated as 9.45 μm of mylar.

Note that for most experiments, we never have 2 PPACs at F2.

If you want to get really precise, you should properly just do the energy loss for the PPAC as appropriate layers of mylar and C3F8 gas at ~8.5 Torr, but I digress...

        (__)               __(^^)              /   /    (__)      / PhD  \  (oO)     /|  /---^^---/     / | /| daid  ||    *  || ||------||
Next pageNext page