OptiM32 HRRL PositronDesign

Software

Optim32 beamline design software

http://www-bdnew.fnal.gov/pbar/organizationalchart/lebedev/OptiM/optim.htm

G4Beamline

http://www.muonsinc.com/tiki-index.php?page=G4beamline

Quick Start

The instruction below assume you have successfully installed the software above.

Create the *.in files

On the windows machine you can open the file below which represent one design for the HRRL positron source

File:Optim32 HRRL Design Script V1.0.txt

save the above file as HRRL.opt.

The launch the Optim executable by double clicking.

After it is launched click on the "file" menu in the GUI and select the "Open" menu item to choose the file HRRL.opt.

After it is loaded you should see the following below.

If you click on the icon with the [math]\beta \psi[/math] symbols (9th button from the end of the tool bar) you can get a plot of the beam dispersion

This is an interactive display. You can adjust values in the loaded text vile and watch their effect on the dispersion. Notice the colored rectangles at the colored rectangles at the bottom of the beta curve sub window. Starting from the left bottom there are 3 read rectangles , a blue rectangle, then 3 red rectangles, a blue rectangle, and finally 3 more red rectangles. The red rectangles are the quadrupoles in the beam line and the blue rectangles are the dipoles. If you click on them their element name will appear in the upper right corner of the dispersion sub window.

If you scroll down the HRRL.opt input file to line which says

begin list

you will se a list of all the elements, the B-field values, their lengths, etc...

If you scroll down to the first quad

q0 	L[cm]=13         	G[kG/cm]=0.0438324 	Tilt[deg]=0

you can move the curser the the B-field value "G[kG/cm]=0.0438324" and increment it while watch the effect on the dispersion plot. You increments it hitting the left and right arrow keys while holding down the "Crtl" key. The value of the increment step is controlled by through the parameters available in the dialog box you get when you select "Steps" from the "Edit" menu.

The above says the quadrupole B-field step size is set to 0.005.

Let's assume you have finished a design and now you would like to simulate the beam line using G4beamline.

Create a text file by selecting "Lattice" from the "View" menu (Alt-L is the shortcut key) and click OK when the dialog box appears below.

Clicking "OK" in the dialog box will cause a text window to open up which looks like the image below.

Save the list of elements to a text file. The text window contains other text you don't need for G4bemline. The following is the text file which was written for this example

N 	Name 	S[cm] 	L[cm] 	B[kG] 	G[kG/cm]   S[kG/cm/cm] 	Tilt[deg] 	Tilt_out 	BendAng[deg]
1 	oD0 	4.03293 	4.03293  
2 	q0 	17.0329 	13 	0 	0.0338324 	0 	0
3 	oD1 	20.5462 	3.51326  
4 	q1 	33.5462 	13 	0 	-0.0651436 	0 	0
5 	oD2 	39.5285 	5.9823  
6 	q2 	52.5285 	13 	0 	0.0449155 	0 	0
7 	oD3 	62.18 	9.65149  
8 	gC1 	62.18 	0 	0  Angle[deg]=0  Eff.Length[cm]=0  Tilt[deg]=0
9 	bC1 	92.18 	30 	-0.315179 	0 	0 	0 	0 	-54.1377
10 	GC1 	92.18 	0 	0  Angle[deg]=0  Eff.Length[cm]=0  Tilt[deg]=0
11 	oD7 	108.98 	16.8  
12 	q6 	121.98 	13 	0 	-0.0190153 	0 	0
13 	oD8 	132.68 	10.7  
14 	q7 	145.68 	13 	0 	0.0365559 	0 	0
15 	oD9 	158.13 	12.45  
16 	q8 	171.13 	13 	0 	-0.0231326 	0 	0
17 	oD10 	182.03 	10.9  
18 	gC2 	182.03 	0 	0  Angle[deg]=0  Eff.Length[cm]=0  Tilt[deg]=0
19 	bC2 	212.03 	30 	-0.285179 	0 	0 	0 	0 	-48.9847
20 	GC2 	212.03 	0 	0  Angle[deg]=0  Eff.Length[cm]=0  Tilt[deg]=0
21 	oD11 	242.03 	30  
22 	q9 	262.03 	20 	0 	0.0119605 	0 	0
23 	oD12 	266.541 	4.51061  
24 	q10 	286.541 	20 	0 	-0.00837701 	0 	0
25 	oD13 	292.532 	5.99133  
26 	q11 	312.532 	20 	0 	0.0031277 	0 	0
27 	oD14 	513.032 	200.5  

Save the above file under the file HRRL.txt or any simular name

Converting text file for G4beamline

A perl script has been written to convert the above list of beamline elements into a G4beamline input file.

the syntax is

perl optim2g4beam.pl HRRL.txt

The perl script write the file z_positions.in based on the contents of the HRRL.txt file.

Below is the resulting z_positions.in file

place QType13 gradient=0.518324 z=105.33 rename=q0
place QType13 gradient=-0.631436 z=270.46 rename=q1
place QType13 gradient=0.239155 z=460.29 rename=q2
tune bC1 z0=471.16 z1=971.16 initial=-0.03151790 step=0.00001 expr=atan(Px1/Pz1) tolerance=0.0000001
place SECT_BEND2 By=bC1 z=-0.032 rename=571.164
cornerarc C1 z=571.164 centerRadius=381.971943 angle=45.000000
place QType13 gradient=-0.190153 z=1104.16 rename=q6
place QType13 gradient=0.415559 z=1341.16 rename=q7
place QType13 gradient=-0.228326 z=1595.66 rename=q8
tune bC1 z0=1619.03 z1=2119.03 initial=-0.03151790 step=0.00001 expr=atan(Px1/Pz1) tolerance=0.0000001
place SECT_BEND2 By=bC1 z=-0.032 rename=1719.03
cornerarc C1 z=1719.030 centerRadius=381.971943 angle=45.000000
place QType20 gradient=-0.010395 z=2419.03 rename=q9
place QType20 gradient=0.056230 z=2664.13 rename=q10
place QType20 gradient=-0.008723 z=2924.05 rename=q11

Currently there is a bug in the perl script such that the 90 degree bending magnet "bC1" has its name repeated and the z position is a negative number because the actual z position is listed after the "rename=" field

so change line 10 and 11 from

tune bC1 z0=471.16 z1=971.16 initial=-0.03151790 step=0.00001 expr=atan(Px1/Pz1) tolerance=0.0000001
place SECT_BEND2 By=bC1 z=-0.032 rename=571.164

to

tune bC1 z0=471.16 z1=971.16 initial=-0.03151790 step=0.001 expr=atan(Px1/Pz1) tolerance=0.0001
place SECT_BEND2 By=bC1 z=571.164 rename=571.164

and line 15 and 16 from

 tune bC1 z0=1619.03 z1=2119.03 initial=-0.03151790 step=0.00001 expr=atan(Px1/Pz1) tolerance=0.0000001
place SECT_BEND2 By=bC1 z=-0.032 rename=1719.03

to

tune bC2 z0=1619.03 z1=2119.03 initial=-0.03151790 step=0.001 expr=atan(Px1/Pz1) tolerance=0.0001
place SECT_BEND2 By=bC2 z=1719.03 rename=1719.03

creating virtual detectors

Virtual detector may be created to intercept the particles traveling down the beam pipe to record their momentum and position at specified locations along the beam line.