elements

label:keyword, attribute,..., attribute

QF: QUADRUPOLE, L=1.8, K1=0.015832;

label:DRIFT, TYPE=string, APERTURE=string, L=real;

DR1:DRIFT, L=1.5;
DR2:DRIFT, L=DR1->L, TYPE=DRF;

An RBEND is a rectangular bending magnet. The key property of an RBEND is that it has parallel pole faces. Figure [rbend] shows an RBEND with a positive bend angle and a positive entrance edge angle.

L

Physical length of magnet (meters, see Figure [rbend]).

GAP

Full vertical gap of the magnet (meters).

HAPERT

Non-bend plane aperture of the magnet (meters). (Defaults to one half the bend radius.)

ANGLE

Bend angle (radians). Field amplitude of bend will be adjusted to achieve this angle. (Note that for an RBEND, the bend angle must be less than \frac{\pi}{2} + E1, where E1 is the entrance edge angle.)

K0

Field amplitude in y direction (Tesla). If the ANGLE attribute is set, K0 is ignored.

K0S

Field amplitude in x direction (Tesla). If the ANGLE attribute is set, K0S is ignored.

K1

Field gradient index of the magnet, K_1=-\frac{R}{B_{y}}\frac{\partial B_y}{\partial x}, where R is the bend radius as defined in Figure [rbend]. Not supported in DOPAL-t any more. Superimpose a Quadrupole instead.

E1

Entrance edge angle (radians). Figure [rbend] shows the definition of a positive entrance edge angle. (Note that the exit edge angle is fixed in an RBEND element to \mathrm{E2} = \mathrm{ANGLE} - \mathrm{E1}).

DESIGNENERGY

Energy of the reference particle (MeV). The reference particle travels approximately the path shown in Figure [rbend].

FMAPFN

Name of the field map for the magnet. Currently maps of type 1DProfile1 can be used see Section [1DProfile1]. The default option for this attribute is FMAPN = 1DPROFILE1-DEFAULT see Section [benddefaultfieldmapopalt]. The field map is used to describe the fringe fields of the magnet see Section [1DProfile1].

An RBEND3D3D is a rectangular bending magnet. The key property of an RBEND3D is that it has parallel pole faces. Figure [rbend] shows an RBEND3D with a positive bend angle and a positive entrance edge angle.

L

Physical length of magnet (meters, see Figure [rbend]).

GAP

Full vertical gap of the magnet (meters).

HAPERT

Non-bend plane aperture of the magnet (meters). (Defaults to one half the bend radius.)

ANGLE

Bend angle (radians). Field amplitude of bend will be adjusted to achieve this angle. (Note that for an RBEND3D, the bend angle must be less than \frac{\pi}{2} + E1, where E1 is the entrance edge angle.)

K0

Field amplitude in y direction (Tesla). If the ANGLE attribute is set, K0 is ignored.

K0S

Field amplitude in x direction (Tesla). If the ANGLE attribute is set, K0S is ignored.

K1

Field gradient index of the magnet, K_1=-\frac{R}{B_{y}}\frac{\partial B_y}{\partial x}, where R is the bend radius as defined in Figure [rbend]. Not supported in DOPAL-t any more. Superimpose a Quadrupole instead.

E1

Entrance edge angle (radians). Figure [rbend] shows the definition of a positive entrance edge angle. (Note that the exit edge angle is fixed in an RBEND3D element to \mathrm{E2} = \mathrm{ANGLE} - \mathrm{E1}).

DESIGNENERGY

Energy of the reference particle (MeV). The reference particle travels approximately the path shown in Figure [rbend].

FMAPFN

Name of the field map for the magnet. Currently maps of type 1DProfile1 can be used see Section [1DProfile1]. The default option for this attribute is FMAPN = 1DPROFILE1-DEFAULT see Section [benddefaultfieldmapopalt]. The field map is used to describe the fringe fields of the magnet see Section [1DProfile1].

An SBEND is a sector bending magnet. An SBEND can have independent entrance and exit edge angles. Figure [sbend] shows an SBEND with a positive bend angle, a positive entrance edge angle, and a positive exit edge angle.

L

Chord length of the bend reference arc in meters (see Figure [sbend]), given by: L = 2 R \sin\left(\frac{\alpha}{2}\right)

GAP

Full vertical gap of the magnet (meters).

HAPERT

Non-bend plane aperture of the magnet (meters). (Defaults to one half the bend radius.)

ANGLE

Bend angle (radians). Field amplitude of the bend will be adjusted to achieve this angle. (Note that practically speaking, bend angles greater than \frac{3 \pi}{2} (270 degrees) can be problematic. Beyond this, the fringe fields from the entrance and exit pole faces could start to interfere, so be careful when setting up bend angles greater than this. An angle greater than or equal to 2 \pi (360 degrees) is not allowed.)

K0

Field amplitude in y direction (Tesla). If the ANGLE attribute is set, K0 is ignored.

K0S

Field amplitude in x direction (Tesla). If the ANGLE attribute is set, K0S is ignored.

K1

Field gradient index of the magnet, K_1=-\frac{R}{B_{y}}\frac{\partial B_y}{\partial x}, where R is the bend radius as defined in Figure [sbend]. Not supported in DOPAL-t any more. Superimpose a Quadrupole instead.

E1

Entrance edge angle (rad). Figure [sbend] shows the definition of a positive entrance edge angle.

E2

Exit edge angle (rad). Figure [sbend] shows the definition of a positive exit edge angle.

DESIGNENERGY

Energy of the bend reference particle (MeV). The reference particle travels approximately the path shown in Figure [sbend].

FMAPFN

Name of the field map for the magnet. Currently maps of type 1DProfile1 can be used see Section [1DProfile1]. The default option for this attribute is FMAPN = 1DPROFILE1-DEFAULT see Section [benddefaultfieldmapopalt]. The field map is used to describe the fringe fields of the magnet see Section [1DProfile1].

Describing an RBEND or an SBEND in an OPAL-t simulation requires effectively identical commands. There are only slight differences between the two. The L attribute has a different definition for the two types of bends see Section [RBend,SBend], and an SBEND has an additional attribute E2 that has no effect on an RBEND, see Section [SBend]. Therefore, in this section, we will give several examples of how to implement a bend, using the RBEND and SBEND commands interchangeably. The understanding is that the command formats are essentially the same.

When implementing an RBEND or SBEND in an OPAL-t simulation, it is important to note the following:

1. Internally OPAL-t treats all bends as positive, as defined by Figure [rbend,sbend]. Bends in other directions within the x/y plane are accomplished by rotating a positive bend about its z axis.

2. If the ANGLE attribute is set to a non-zero value, the K0 and K0S attributes will be ignored.

3. When using the ANGLE attribute to define a bend, the actual beam will be bent through a different angle if its mean kinetic energy doesn’t correspond to the DESIGNENERGY.

4. Internally the bend geometry is setup based on the ideal reference trajectory, as shown in Figure [rbend,sbend].

5. If the default field map, 1DPROFILE-DEFAULT see Section [benddefaultfieldmapopalt], is used, the fringe fields will be adjusted so that the effective length of the real, soft edge magnet matches the ideal, hard edge bend that is defined by the reference trajectory.

For the rest of this section, we will give several examples of how to input bends in an OPAL-t simulation. We will start with a simple example using the ANGLE attribute to set the bend strength and using the default field map see Section [benddefaultfieldmapopalt] for describing the magnet fringe fields see Section [1DProfile1]:

This is a definition of a simple RBEND that bends the beam in a positive direction 30 degrees (towards the negative x axis as if Figure [rbend]). It has a design energy of 10MeV, a length of 0.5m, a vertical gap of 2cm and a 0^{\circ} entrance edge angle. (Therefore the exit edge angle is 30^{\circ}.) We are using the default, internal field map "1DPROFILE1-DEFAULT" see Section [benddefaultfieldmapopalt] which describes the magnet fringe fields see Section [1DProfile1]. When OPAL is run, you will get the following output (assuming an electron beam) for this RBEND definition:

The first section of this output gives the properties of the reference trajectory like that described in Figure [rbend]. From the value of ANGLE and the length, L, of the magnet, OPAL calculates the 10MeV reference particle trajectory radius, R. From the bend geometry and the entrance angle (0^{\circ} in this case), the exit angle is calculated.

The second section gives the field amplitude of the bend and its gradient (quadrupole focusing component), given the particle charge (-e in this case so the amplitude is negative to get a positive bend direction). Also listed is the rotation of the magnet about the various axes.

Of course, in the actual simulation the particles will not see a hard edge bend magnet, but rather a soft edge magnet with fringe fields described by the RBEND field map file FMAPFN see Section [1DProfile1]. So, once the hard edge bend/reference trajectory is determined, OPAL then includes the fringe fields in the calculation. When the user chooses to use the default field map, OPAL will automatically adjust the position of the fringe fields appropriately so that the soft edge magnet is equivalent to the hard edge magnet described by the reference trajectory. To check that this was done properly, OPAL integrates the reference particle through the final magnet description with the fringe fields included. The result is shown in the final part of the output. In this case we see that the soft edge bend does indeed bend our reference particle through the correct angle.

What is important to note from this first example, is that it is this final part of the bend output that tells you the actual bend angle of the reference particle.

In this next example, we merely rewrite the first example, but use K0 to set the field strength of the RBEND, rather than the ANGLE attribute:

The output from OPAL now reads as follows:

The output is effectively identical, to within a small numerical error.

Now, let us modify this first example so that we bend instead in the negative x direction. There are several ways to do this:

1.

2.

3.

4.

In each of these cases, we get the following output for the bend (to within small numerical errors).

In general, we suggest to always define a bend in the positive x direction (as in Figure [rbend]) and then use the ROTATION attribute to bend in other directions in the x/y plane (as in examples 2 and 4 above).

As a final RBEND example, here is a suggested format for the four bend definitions if one where implementing a four dipole chicane:

Up to now, we have only given examples of RBEND definitions. If we replaced "RBend" in the above examples with "SBend", we would still be defining valid OPAL-t bends. In fact, by adjusting the L attribute according to Section [RBend,SBend], and by adding the appropriate definitions of the E2 attribute, we could even get identical results using `SBEND`s instead of `RBEND`s. (As we said, the two bends are very similar in command format.)

Up till now, we have only used the default field map. Custom field maps can also be used. There are two different options in this case see Section [1DProfile1]:

1. Field map defines fringe fields and magnet length.

2. Field map defines fringe fields only.

The first case describes how field maps were used in previous versions of OPAL (and can still be used in the current version). The second option is new to OPAL OPALversion1.2.00 and it has a couple of advantages:

1. Because only the fringe fields are described, the length of the magnet must be set using the L attribute. In turn, this means that the same field map can be used by many bend magnets with different lengths (assuming they have equivalent fringe fields). By contrast, if the magnet length is set by the field map, one must generate a new field map for each dipole of different length even if the fringe fields are the same.

2. We can adjust the position of the fringe field origin relative to the entrance and exit points of the magnet see Section [1DProfile1]. This gives us another degree of freedom for describing the fringe fields, allowing us to adjust the effective length of the magnet.

We will now give examples of how to use a custom field map, starting with the first case where the field map describes the fringe fields and the magnet length. Assume we have the following 1DProfile1 field map:

We can use this field map to define the following bend (note we are now using the SBEND command):

Notice that we do not set the magnet length using the L attribute. (In fact, we don’t even include it. If we did and set it to a non-zero value, the exit fringe fields of the magnet would not be correct.) This input gives the following output:

Because we set the bend strength using the ANGLE attribute, the magnet field strength is automatically adjusted so that the reference particle is bent exactly ANGLE radians when the fringe fields are included. (Lower output.)

Now we will illustrate the case where the magnet length is set by the L attribute and only the fringe fields are described by the field map. We change the TEST-MAP.T7 file to:

and change the bend input to:

This results in the same output as the previous example, as we expect.

As a final example, let us now use the previous field map with the following input:

Instead of setting the bend strength using ANGLE, we use K0. This results in the following output:

In this case, the bend angle for the reference trajectory in the first section of the output no longer matches the reference trajectory bend angle from the lower section (although the difference is small). The reason is that the path of the reference particle through the real magnet (with fringe fields) no longer matches the ideal trajectory. (The effective length of the real magnet is not quite the same as the hard edged magnet for the reference trajectory.)

We can compensate for this by changing the field map file TEST-MAP.T7 file to:

We have moved the Enge function origins see Section [1DProfile1] outward from the entrance and exit faces of the magnet see Section [1DProfile1] by 0.3026 mm. This has the effect of making the effective length of the soft edge magnet longer. When we do this, the same input:

produces

Now we see that the bend angle for the ideal, hard edge magnet, matches the bend angle of the reference particle through the soft edge magnet. In other words, the effective length of the soft edge, real magnet is the same as the hard edge magnet described by the reference trajectory.

So far we have described how to setup an RBEND or SBEND element, but have not explained how OPAL-t uses this information to calculate the magnetic field. The field of both types of magnets is divided into three regions:

1. Entrance fringe field.

2. Central field.

3. Exit fringe field.

This can be seen clearly in Figure [rbend_field_profile].

The purpose of the 1DProfile1 field map see Section [1DProfile1] associated with the element is to define the Enge functions (Equation [enge_func]) that model the entrance and exit fringe fields. To model a particular bend magnet, one must fit the field profile along the mid-plane of the magnet perpendicular to its face for the entrance and exit fringe fields to the Enge function:

where D is the full gap of the magnet, N_{order} is the Enge function order and z is the distance from the origin of the Enge function perpendicular to the edge of the dipole. The origin of the Enge function, the order of the Enge function, N_{order}, and the constants c_0 to c_{N_{order}} are free parameters that are chosen so that the function closely approximates the fringe region of the magnet being modeled. An example of the entrance fringe field is shown in Figure [rbend_enge_fringe].

Let us assume we have a correctly defined positive RBEND or SBEND element as illustrated in Figure [rbend,sbend]. (As already stated, any bend can be described by a rotated positive bend.) OPAL-t then has the following information:

Here, we have defined an overall Enge function, F(z), with three parts: entrance, center and exit. The exit and entrance fringe field regions have the form of Equation [enge_func] with parameters defined by the 1DProfile1 field map file given by the element parameter FMAPFN. Defining the coordinates:

using the conditions

and making the definitions:

we can expand the field off axis, with the result:

These expression are not well suited for numerical calculation, so, we expand them about y to O(y^2) to obtain:

• In fringe field regions:

• In central region:

These are the expressions OPAL-t uses to calculate the field inside an RBEND or SBEND. First, a particle’s position inside the bend is determined (entrance region, center region, or exit region). Depending on the region, OPAL-t then determines the values of \Delta_x, y and \Delta_z, and then calculates the field values using the above expressions.

Rather than force users to calculate the field of a dipole and then fit that field to find Enge coefficients for the dipoles in their simulation, we have a default set of values we use from [enge] that are set when the default field map, 1DPROFILE1-DEFAULT is used:

The same values are used for both the entrance and exit regions of the magnet. In general they will give good results. (Of course, at some point as a beam line design becomes more advanced, one will want to find Enge coefficients that fit the actual magnets that will be used in a given design.)

The default field map is the equivalent of the following custom 1DProfile1 (see Section [1DProfile1] for an explanation of the field map format) map:

As one can see, the default magnet gap for 1DPROFILE1-DEFAULT is set to 2.0cm. This value can be overridden by the GAP attribute of the magnet (see Section [RBend,SBend]).

The SBend3D element enables definition of a bend from 3D field maps. This can be used in conjunction with the RINGDEFINITION element to make a ring for tracking through OPAL-cycl.

FMAPFN

The field map file name.

LENGTH_UNITS

Units for length (set to 1.0 for units in mm, 10.0 for units in cm, etc).

FIELD_UNITS

Units for field (set to 1.0 for units in T, 0.001 for units in mT, etc).

Field maps are defined using Cartesian coordinates but in a polar geometry with the following restrictions/conventions:

1. 3D Field maps have to be generated in the vertical direction (z coordinate in OPAL-cycl) from z = 0 upwards. It cannot be generated symmetrically about z = 0 towards negative z values.

2. Field map file must be in the form with columns ordered as follows: [x, z, y, B_{x}, B_{z}, B_{y}].

3. Grid points of the position and field strength have to be written on a grid in (r, z, \theta) with the primary direction corresponding to the azimuthal direction, secondary to the vertical direction and tertiary to the radial direction.

Below two examples of a SBEND3D which loads a field maps with different units. The triplet example has units of cm and fields units of Gauss, where the Dipole example (Figure [sbend3d1]) uses meter and Tesla. The first 8 lines in the field map are ignored.

The first few links of the field map fdf-tosca-field-map.table:

The first few links of the field map 90degree_Dipole_Magnet.out:

This is a restricted feature: OPAL-cycl.

label:QUADRUPOLE, TYPE=string, APERTURE=real-vector,
      L=real, K1=real, K1S=real;

QP1: Quadrupole, L=1.20, ELEMEDGE=-0.5265,
     FMAPFN="1T1.T7", K1=0.11;

label: SEXTUPOLE, TYPE=string, APERTURE=real-vector,
       L=real, K2=real, K2S=real;

S:SEXTUPOLE, L=0.4, K2=0.00134;

label:OCTUPOLE, TYPE=string, APERTURE=real-vector,
      L=real, K3=real, K3S=real;

O3:OCTUPOLE, L=0.3, K3=0.543;

label:MULTIPOLE, TYPE=string, APERTURE=real-vector,
      L=real, KN=real-vector, KS=real-vector;

M27:MULTIPOLE, L=1, ELEMEDGE=3.8, KN={0.0,0.11};

label:MULTIPOLET, L=real, ANGLE=real, VAPERT=real, HAPERT=real,
      LFRINGE=real, RFRINGE=real, TP=real-vector, VARRADIUS=bool;

label:SOLENOID, TYPE=string, APERTURE=real-vector,
      L=real, KS=real;

SP1: Solenoid, L=1.20, ELEMEDGE=-0.5265, KS=0.11,
     FMAPFN="1T1.T7";

label:CYCLOTRON, TYPE=string, CYHARMON=int,
      PHIINIT=real, PRINIT=real, RINIT=real,
      SYMMETRY=real, RFFREQ=real, FMAPFN=string;

ring: Cyclotron, TYPE="RING", CYHARMON=6, PHIINIT=0.0,
      PRINIT=-0.000240, RINIT=2131.4 , SYMMETRY=8.0,
      RFFREQ=50.650, FMAPFN="s03av.nar",
      MAXZ=10, MINZ=-10, MINR=0, MAXR=2500;

COMET: Cyclotron, TYPE="BANDRF", CYHARMON=2, PHIINIT= -71.0,
PRINIT=pr0, RINIT= r0 , SYMMETRY=1.0, FMAPFN="Tosca_map.txt",
RFPHI=Pi, RFFREQ=72.0,  RFMAPFN="efield.h5part",
ESCALE=1.06E-6;

COMET: Cyclotron, TYPE="BANDRF", CYHARMON=2, PHIINIT=-71.0,
PRINIT=pr0, RINIT=r0 , SYMMETRY=1.0, FMAPFN="Tosca_map.txt",
RFPHI= {Pi,0,Pi,0}, RFFREQ={72.0,72.0,72.0,72.0},
RFMAPFN={"e1.h5part","e2.h5part","e3.h5part","e4.h5part"},
ESCALE={1.06E-6, 3.96E-6,1.3E-6,1.E-6}, SUPERPOSE=true;

label: RINGDEFINITION,
       RFFREQ=real, HARMONIC_NUMBER=real, IS_CLOSED=string, SYMMETRY=int,
       LAT_RINIT=real, LAT_PHIINIT=real, LAT_THETAINIT=real,
       BEAM_PHIINIT=real, BEAM_PRINIT=real, BEAM_RINIT=real;

ringdef: RINGDEFINITION, HARMONIC_NUMBER=6, LAT_RINIT=2350.0, LAT_PHIINIT=0.0,
         LAT_THETAINIT=0.0, BEAM_PHIINIT=0.0, BEAM_PRINIT=0.0,
         BEAM_RINIT=2266.0, SYMMETRY=4.0, RFFREQ=0.2;

The LOCAL_CARTESIAN_OFFSET enables the user to place an object at an arbitrary position in the coordinate system of the preceding element. This enables drift spaces and placement of overlapping elements.

END_POSITION_X

x position of the next element start in the coordinate system of the preceding element [mm].

END_POSITION_Y

y position of the next element start in the coordinate system of the preceding element [mm].

END_NORMAL_X

x component of the normal vector defining the placement of the next element in the coordinate system of the preceding element.

END_NORMAL_Y

y component of the normal vector defining the placement of the next element in the coordinate system of the preceding element.

label:RFCAVITY, APERTURE=real-vector, L=real,
      VOLT=real, LAG=real;

Using a RF Cavity in OPAL-t mode, the following additional parameters are defined:

FMAPFN

Field maps in the T7 format can be specified.

TYPE

Type specifies STANDING [default] or SINGLE GAP structures.

FREQ

Defines the frequency of the RF Cavity in units of MHz. A warning is issued when the frequency of the cavity card does not correspond to the frequency defined in the FMAPFN file. The frequency of the cavity card overrides the frequency defined in the FMAPFN file.

APVETO

If TRUE this cavity will not be auto-phased. Instead the phase of the cavity is equal to LAG at the arrival time of the reference particle (arrival at the limit of its field not at ELEMEDGE).

Example standing wave cavity which mimics a DC gun:

Example of a two frequency standing wave cavity:

Using a RF Cavity (standing wave) in OPAL-cycl mode, the following parameters are defined:

FMAPFN

Defines name of file which stores normalized voltage amplitude curve of cavity gap in ASCII format. (See data format in Section [opalcycl:rffieldmap])

VOLT

Sets peak value of voltage amplitude curve in MV.

TYPE

Defines Cavity type, SINGLEGAP represents cyclotron type cavity.

FREQ

Sets the frequency of the RF Cavity in units of MHz.

RMIN

Sets the radius of the cavity inner edge in mm.

RMAX

Sets the radius of the cavity outer edge in mm.

ANGLE

Sets the azimuthal position of the cavity in global frame in degree.

PDIS

Set shift distance of cavity gap from center of cyclotron in mm. If its value is positive, the shift direction is clockwise, namely, shift towards the smaller azimuthal angle.

GAPWIDTH

Set gap width of cavity in mm.

PHI0

Set initial phase of cavity in degree.

Example of a RF cavity of cyclotron:

Figure [Cyclotron_cavity] shows the simplified geometry of a cavity gap and its parameters.

The POLYNOMIAL_TIME_DEPENDENCE element is used to define time dependent parameters in RF cavities in terms of a third order polynomial.

P0

Constant term in the polynomial expansion.

P1

First order term in the polynomial expansion [ns^{-1}].

P2

Second order term in the polynomial expansion [ns^{-2}].

P3

Third order term in the polynomial expansion [ns^{-3}].

The polynomial is evaluated as

An example of a Variable Frequency RF cavity of cyclotron with polynomial time dependence of parameters is given below:

label:TRAVELINGWAVE, APERTURE=real-vector, L=real,
      VOLT=real, LAG=real, FMAPFN=string,
      ELEMEDGE=real, FREQ=real, NUMCELLS=integer,
      MODE=real;

lrf0: TravelingWave, L=0.0253, VOLT=14.750,
      NUMCELLS=40, ELEMEDGE=2.73066,
      FMAPFN="INLB-02-RAC.Ez", MODE=1/3,
      FREQ=1498.956, LAG=248.0/360.0;

label:ECOLLIMATOR, TYPE=string, APERTURE=real-vector,
      L=real, XSIZE=real, YSIZE=real;
label:RCOLLIMATOR,TYPE=string, APERTURE=real-vector,
      L=real, XSIZE=real, YSIZE=real;

COLLIM:ECOLLIMATOR, L=0.5, XSIZE=0.01, YSIZE=0.005;

The CCOLLIMATOR isn’t supported. ECOLLIMATORs and RCOLLIMATORs detect all particles which are outside the aperture defined by XSIZE and YSIZE. Lost particles are saved in an H5hut file defined by OUTFN. The ELEMEDGE defines the location of the collimator and L the length.

OUTFN

The file name into which the monitor should write the collected data. The file is an H5hut file.

Example:

Only CCOLLIMATOR is available for OPAL-cycl. This element is radial rectangular collimator which can be used to collimate the radial tail particles. So when a particle hit this collimator, it will be absorbed or scattered, the algorithm is based on the Monte Carlo method . Pleased note when a particle is scattered, it will not be recorded as the lost particle. If this particle leave the bunch, it will be removed during the integration afterwards, so as to maintain the accuracy of space charge solving.

XSTART

The x coordinate of the start point. [mm]

XEND

The x coordinate of the end point. [mm]

YSTART

The y coordinate of the start point. [mm]

YEND

The y coordinate of the end point. [mm]

ZSTART

The vertical coordinate of the start point [mm]. Default value is -100mm.

ZEND

The vertical coordinate of the end point. [mm]. Default value is -100mm.

WIDTH

The width of the septum. [mm]

PARTICLEMATTERINTERACTION

PARTICLEMATTERINTERACTION is an attribute of the element. Collimator physics is only a kind of particlematterinteraction. It can be applied to any element. If the type of PARTICLEMATTERINTERACTION is COLLIMATOR, the material is defined here. The material "Cu", "Be", "Graphite" and "Mo" are defined until now. If this is not set, the particle matter interaction module will not be activated. The particle hitting collimator will be recorded and directly deleted from the simulation.

Example:

The particles lost on the CCOLLIMATOR are recorded in the ASCII file <inputfilename>.loss

eec2: Septum, xstart=4100.0, xend=4300.0,
ystart=-1200.0, yend=-150.0, width=0.05;

prob1: Probe, xstart=4166.16, xend=4250.0,
ystart=-1226.85, yend=-1241.3;

prob1: Stripper, xstart=4166.16, xend=4250.0,
ystart=-1226.85, yend=-1241.3,
opcharge=1, opmass=PMASS, opyield=2, stop=false;

DEGPHYS: PARTICLEMATTERINTERACTION, TYPE="DEGRADER", MATERIAL="Graphite";

DEG1: DEGRADER, L=0.15, ELEMEDGE=0.02, PARTICLEMATTERINTERACTION=DEGPHYS;

label:HKICKER, TYPE=string, APERTURE=real-vector,
      L=real, KICK=real;
label:VKICKER, TYPE=string, APERTURE=real-vector,
      L=real, KICK=real;
label:KICKER, TYPE=string, APERTURE=real-vector,
      L=real, HKICK=real, VKICK=real;

HK1:HKICKER, KICK=0.001;
VK3:VKICKER, KICK=0.0005;
KHV:KICKER, HKICK=0.001, VKICK=0.0005;