Beam Setup and Measurement - May 2018

Energy Setup and Measurement

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Emittance Measurement

Setup beam to FC2

Use qsUtility configuration files to scan MQJ0L02 and/or MQJ0L02A and uses harp IHA0L03

Be sure to enter the correct momentum in the configuration and/or analysis files

Elegant optics lattice begins at MQJ0L02 (that is, use or propagate optics to that location)

Elegant Optics Model

September 2015 - Chris Tennant's Model copied here for reference /usr/opsdata/bubble/elegant/Sep2015

May 2018 - Updated to include 2D spectrometer line and new harp IHA5D01 /usr/opsdata/bubble/elegant/May2018

Energy Spread Measurement

Setup beam to 2D spectrometer dump

Upstream quads MQJ0L02 and MQJ0L02A can be any value but their integrated gradient value B'L (.BL field) must be recorded

Use HarpFitterTool to scan IHA2D00 to measure horizontal beam size

Use Elegant to calculate the horizontal beta (betax) and the horizontal dispersion (etax) at the harp location

Update lattice file

Type command cd /usr/opsdata/bubble/elegant/May2018/lattice

Edit lattice file BubbleChamber.lte

Update K1 values for MQJ0L02/MQJ0L02A (they appear in only one place)

Update energy spread elegant file

Type command cd /usr/opsdata/bubble/elegant/May2018/energy_spread

Edit command file energyspread.ele

Update p_central_mev [MeV/c]

Update beta_x[m] and beta_y[m] with qsUtility values computed at MQJ0L02

Update emit_nx[m-rad] and emit_ny[m-rad] with qsUtility values compated at MQJ0L02

Run Elegant model

Type command cd /usr/opsdata/bubble/elegant/May2018/energy_spread

Type command elegant energyspread.ele

Type command sddsprintout -col=ElementName -col=betax -col=etax energyspread.twi

Record value of betax [m] and etax [m] at IHA2D00

Set Beam at Radiator

Pre-requisites for the measurement

Measured beam momentum in units of MeV/c

Measured normalized emittance and Twiss parameters at MQJ0L02 (e.g. from qsUtility)

Measured relative momentum spread (dp/p) (e.g. 1% is 0.01)

Use Elegant to calculate quad values (MQJ0L02, MQJ0L02A, MQD5D00, MQD5D01) to set beam size at radiator IDL5D01 and compare at harp IHA5D01

Update elegant quad optimization file

Type command cd /usr/opsdata/bubble/elegant/May2018/beam_size

Edit command file BubbleChamber_FIT.ele

Update measured p_central_mev [MeV/c]

Update measured beta_x [m] and beta_y [m] with qsUtility values computed at MQJ0L02

Update measured emit_nx [m-rad] and emit_ny [m-rad] with qsUtility values compated at MQJ0L02

Update measured relative momentum spread sigma_dp

Update desired horizontal beam size by choosing a value of RMSX in this line: term="RADIATOR#1.Sx RMSX 1e-5 sene",

Update desired vertical beam size by choosing a value of RMSY in this line: term="RADIATOR#1.Sx RMSY 1e-5 sene",

Solution is normally calculated with zero dispersion at the radiator. IF this is not desired then comment (put ! in first column) following lines:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

! COMMENT (!) or UNCOMMENT FOR HORIZONTAL DISPERSION AT RADIATOR [m] (e.g. 0 is zero dispersion)

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

&optimization_term

weight=1,

term="RADIATOR#1.etax 0 1e-2 sene",

verbose = 1,

&end