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Changing the quad settings

facet home → Profile Monitor → LI20 → SPEC LINE GUI

New SPECLINE GUI (Fall 2023):

Image AddedImage Removed

  • Leave big "Dipole" switch in "Without" setting (dipole energy is not adjusted)
  • Set "Z Object" to the position where the beam should be imaged, e.g., the center of the PB
  • Set "Z Image" to the position of the screen, e.g., z=2015.26 for DTOTR
    • Note: You can select from a few preassigned beamline locations with the dropdown menu, or, select "custom"
  • M12, M34: transfer-matrix elements (set both to 0 for re-imaging)
  • Energy: determines where the focus is
  • Press "Calculate and Trim"

Assumptions of this script:

  • Magnet length: 1m
    LEFF_QS0 = 1; % [m]
    LEFF_QS1 = 1; % [m]
    LEFF_QS2 = 1; % [m]
  • Quad positions:
    z_QS0 = 1996.98249; % [m], middle of quad
    z_QS1 = 1999.206615; % [m], middle of quad
    z_QS2 = 2001.431049; % [m], middle of quad
  • Other important positions:
    1993.27370    # [m] FILS
    1992.82000    # [m] PIC_CENT
    2015.62984    # [m] LFOV
    2017.52998    # [m] PRDMP

...

Image Removed

...

Image Removed

Changing the dipole settings

  • ATTENTION: there is no possibility to calculate without actually changing the magnets. There will be no elog entry! (2023, Nov 17)
  • Note - the "Trim" button does not do anything yet.


Dump table motors and filters:

IP2 Table on LI20 Profile monitor page:

Image Added

Provides easier access to the dump table flippers (DTOTR1/2, LFOV) and motors.


Scripts for dealing with the spectrometer

...

  • , Nov 13, 2023)

...

...

keep_KQS0_eq_KQS2=1; % set to one if QS0=QS2

E0 = 10;
isok = 1;
if(nargin < 4); m12_req = 0; end;
if(nargin < 5); m34_req = 0; end;

% initial guesses (2012 values)
KQS0_0 = -0.3;
KQS1_0 = 0.23;
KQS2_0 = -0.3;

...

  • .m (FACET MATLAB TNG repo, Nov 13, 2023): script to calculate quad settings
  • espec_trim.py (Sebastian Meuren, Nov 13, 2023)

Assumptions made in this script:

  • Magnet length: 1m
    LEFF_QS0 = 1; % [m]
    LEFF_QS1 = 1; % [m]
    LEFF_QS2 = 1; % [m]

OO = zeros(2,2);

d1 = (z_QS0-LEFF_QS0/2) - z_ob ;
d2 = (z_QS1-LEFF_QS1/2) - (z_QS0+LEFF_QS0/2);
d3 = (z_QS2-LEFF_QS2/2) - (z_QS1+LEFF_QS1/2);
d4 = z_im - (z_QS2+LEFF_QS2/2);

M_01 = [1 d1; 0 1];
M4_01 = [M_01 OO; OO M_01];
M_02 = [1 d2; 0 1];
M4_02 = [M_02 OO; OO M_02];
M_03 = [1 d3; 0 1];
M4_03 = [M_03 OO; OO M_03];
M_04 = [1 d4; 0 1];
M4_04 = [M_04 OO; OO M_04];
options = optimset('TolX',1e-8);  
if keep_KQS0_eq_KQS2
    [fit_result, chi2] = fminsearch(@transportError_2, [KQS0_0 KQS1_0],options);
    BDES0 =  fit_result(1) * (E0+QS) * LEFF_QS0 / 0.0299792458;
    BDES1 =  fit_result(2) * (E0+QS) * LEFF_QS1 / 0.0299792458;
    BDES2 =  fit_result(1) * (E0+QS) * LEFF_QS2 / 0.0299792458;
else
    [fit_result, chi2] = fminsearch(@transportError, [KQS0_0 KQS1_0 KQS2_0],options);
    BDES0 =  fit_result(1) * (E0+QS) * LEFF_QS0 / 0.0299792458;
    BDES1 =  fit_result(2) * (E0+QS) * LEFF_QS1 / 0.0299792458;
    BDES2 =  fit_result(3) * (E0+QS) * LEFF_QS2 / 0.0299792458;
end

...

BMAX = 385; % max value, from SCP
if(abs(BDES1) > BMAX || abs(BDES2) > BMAX || abs(BDES0) > BMAX)
    isok = 0;
    warning('solution is outside QS range');
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    function chi2 = transportError(K)
        % QS0 transport matrix
        k = abs(K(1));
        phi = LEFF_QS0*sqrt(k);
        M_F = [cos(phi)             (1/sqrt(k))*sin(phi)
            -sqrt(k)*sin(phi)    cos(phi)];
        M_D = [cosh(phi)             (1/sqrt(k))*sinh(phi)
            sqrt(k)*sinh(phi)    cosh(phi)];
        M4_D1 = [M_D OO; OO M_F];
        
        % QS1 transport matrix
        k = abs(K(2));
        phi = LEFF_QS1*sqrt(k);
        M_F = [cos(phi)             (1/sqrt(k))*sin(phi)
            -sqrt(k)*sin(phi)    cos(phi)];
        M_D = [cosh(phi)             (1/sqrt(k))*sinh(phi)
            sqrt(k)*sinh(phi)    cosh(phi)];
        M4_F = [M_F OO; OO M_D];
        
        % QS2 transport matrix
        k = abs(K(3));
        phi = LEFF_QS2*sqrt(k);
        M_F = [cos(phi)             (1/sqrt(k))*sin(phi)
            -sqrt(k)*sin(phi)    cos(phi)];
        M_D = [cosh(phi)             (1/sqrt(k))*sinh(phi)
            sqrt(k)*sinh(phi)    cosh(phi)];
        M4_D2 = [M_D OO; OO M_F];

        % dump line optics
        M4 = M4_04*M4_D2*M4_03*M4_F*M4_02*M4_D1*M4_01;
        
        chi2 = (M4(1,2)-m12_req)^2 + (M4(3,4)-m34_req)^2;
    end

    function chi2 = transportError_2(K)
        % QS0 transport matrix
        k = abs(K(1));
        phi = LEFF_QS0*sqrt(k);
        M_F = [cos(phi)             (1/sqrt(k))*sin(phi)
            -sqrt(k)*sin(phi)    cos(phi)];
        M_D = [cosh(phi)             (1/sqrt(k))*sinh(phi)
            sqrt(k)*sinh(phi)    cosh(phi)];
        M4_D1 = [M_D OO; OO M_F];
        
        % QS1 transport matrix
        k = abs(K(2));
        phi = LEFF_QS1*sqrt(k);
        M_F = [cos(phi)             (1/sqrt(k))*sin(phi)
            -sqrt(k)*sin(phi)    cos(phi)];
        M_D = [cosh(phi)             (1/sqrt(k))*sinh(phi)
            sqrt(k)*sinh(phi)    cosh(phi)];
        M4_F = [M_F OO; OO M_D];
        
        % QS2 transport matrix
        k = abs(K(1));
        phi = LEFF_QS2*sqrt(k);
        M_F = [cos(phi)             (1/sqrt(k))*sin(phi)
            -sqrt(k)*sin(phi)    cos(phi)];
        M_D = [cosh(phi)             (1/sqrt(k))*sinh(phi)
            sqrt(k)*sinh(phi)    cosh(phi)];
        M4_D2 = [M_D OO; OO M_F];

        % dump line optics
        M4 = M4_04*M4_D2*M4_03*M4_F*M4_02*M4_D1*M4_01;
        
        chi2 = (M4(1,2)-m12_req)^2 + (M4(3,4)-m34_req)^2;
    end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

end

Python code to reproduce MATLAB settings above (Nov 13, 2023)

...

  • Quad positions:
    z_QS0 = 1996.98249; % [m], middle of quad

...

  • z_QS1 = 1999.206615; % [m], middle of quad

...

  • z_QS2 = 2001.431049; % [m], middle of quad

...

  • Other important positions:
    1993.27370    # [m] FILS

...

  • 1992.82000

...

  •    # [m] PIC_CENT

...

  • 2015.62984    # [m]

...

q1d_pos        = 1999.206615    # [m]
q1d_length    = 1.00            # [m]
q1d_G        = 1.0            # [T/m]

q2d_pos        = 2001.431049    # [m]
q2d_length    = 1.00            # [m]
q2d_G        = 1.0            # [T/m]

...

  • LFOV
    2017.52998    # [m] PRDMP

...

def    get_quad_matrix(length, G, eps):
    # length: [m]
    # G: [T/m]
    # eps: [GeV]
    # omega^2     = qGc^3/(\gamma mc^2)
    # phi        = \omega L /c    
    # sqrt((Tesla / meter) * (elementary charge ) * (speed of light)^3 / GeV)/ (speed of light)
    # \approx 0.5475 (1/meter)
    omegaoverc        = np.sqrt(G/eps) * 0.5475    #[1/m]
    phi                = omegaoverc * length
    return    np.array([[np.cos(phi), (1.0/omegaoverc) * np.sin(phi)], [-omegaoverc * np.sin(phi), np.cos(phi)]])

def    get_quad_matrix_h(length, G, eps):
    # length: [m]
    # G: [T/m]
    # eps: [GeV]
    omegaoverc        = np.sqrt(G/eps) * 0.5475    #[1/m]
    phi                = omegaoverc * length
    return    np.array([[np.cosh(phi), (1.0/omegaoverc) * np.sinh(phi)], [omegaoverc * np.sinh(phi), np.cosh(phi)]])

...

#d1 = (z_QS0-LEFF_QS0/2) - z_ob ;
#d2 = (z_QS1-LEFF_QS1/2) - (z_QS0+LEFF_QS0/2);
#d3 = (z_QS2-LEFF_QS2/2) - (z_QS1+LEFF_QS1/2);
#d4 = z_im - (z_QS2+LEFF_QS2/2);

...

    current    = get_free_matrix(q0d_pos-q0d_length/2.0-xstart)
    next    = None
    if(getx == True):
        next    = get_quad_matrix_h(q0d_length, G_out, eps)
    else:
        next    = get_quad_matrix(q0d_length, G_out, eps)
    current    = np.matmul(next, current)
    next    = get_free_matrix((q1d_pos-q1d_length/2.0)-(q0d_pos+q0d_length/2.0))
    current    = np.matmul(next, current)
    if(getx == True):
        next    = get_quad_matrix(q1d_length, G_in, eps)
    else:
        next    = get_quad_matrix_h(q1d_length, G_in, eps)
    current    = np.matmul(next, current)
    next    = get_free_matrix((q2d_pos-q2d_length/2.0)-(q1d_pos+q1d_length/2.0))
    current    = np.matmul(next, current)
    if(getx == True):
        next    = get_quad_matrix_h(q2d_length, G_out, eps)
    else:
        next    = get_quad_matrix(q2d_length, G_out, eps)
    current    = np.matmul(next, current)
    next    = get_free_matrix(xend-(q2d_pos+q2d_length/2.0))
    current    = np.matmul(next, current)
    return current

...


Image Added

Image Added

Quad PVs

  • LI20:LGPS:3141:BACT
  • LI20:LGPS:3261:BACT
  • LI20:LGPS:3091:BACT
  • Dipole: LI20:LGPS:3330:BACT

BPMs

  • #BPM before IP: 3156
    bpm_3156_z            = 1991.29
  • #BPM Q0:        3218
    bpm_3218_z            = 1997.77
  • #BPM Q1:        3265
    bpm_3265_z            = 2000.0
  • #BPM Q2:        3315
    bpm_3315_z            = 2002.22

Quad Scan functions

  • Spec_Quad_E (change energy for which the imaging conditions are calculated)
  • Spec_Quad_M12 (angle at object plane to position at image plane matrix element: horizontal axis)
  • Spec_Quad_M34 (angle at object plane to position at image plane matrix element: vertical axis)
  • Spec_Quad_zim  (position of image plane)
  • Spec_Quad_zob (position of object plane)

Changing the dipole settings

  • It is important that the e-beam never passes through the CsI array (see Dump-table electron diagnostics)

  • BNDS_LI20_3330 scan function
    for LFOV: 6 to 22. Never go higher than 22!

from scipy.optimize import fmin

...