man3scale/scale_formulae

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Name

scale_formulae - formulas used by the libscale(3) package

Description

This manual page describes the formulas and procedures used by the various components of the libscale(3scale) software package.

Magnetic components

At this time all magnetic components (bending magnets, magnetic quads, and magnetic steererer) are all treated in the same way.

Bn = new field strength
En = new particle energy
Mn = new particle mass
Qn = new charge state

Bo = old field strength
Eo = old particle energy
Mo = old particle mass
Qo = old charge state

Num = (Mn * En) / (Qo * Qo)
Den = (Mo * Eo) / (Qn * Qn)
Bnew = sqrt (Num / Den) * Bold

Electrostatic components

At this time all electrostatic quads, and steerers are scaled in this way.

Vn = new element voltage
En = new particle energy
Qn = new charge state

Vo = old element voltage
Eo = old particle energy
Qo = old charge state

Vn = ((En / Qo) / (Eo / Qn)) * Vo

Low Energy Einzel Lens components

Low energy einzel lens represent a special case in the accelerator scaling software because there is interaction between the accelerating tube and lens settings. At this time the scaling software does not handle this case correctly.

If "initial run" is selected the input value is copied to the output, i.e. no scaling is performed.

Vn = new element voltage
Vo = old element voltage
Vn = Vo

If "scale run" is selected, then the scaling is performed by the electrostatic scaling rule. See Electrostatic components for more information.

Charging voltage calculation

The charging voltage is calculated by first finding the desired charging current then calculating the charging voltage needed to obtain this current.

Nchain = number of charging chains
Ichain = chain constant (uA/KV)
Itotal = total charging current
V = required charging voltage

V = Itotal / (Nchain * Ichain)

Charging current calculation

The charging current calculation is used to find the correct charging voltage.

SRmaxHE = max number of HE shorting rods
SRmaxLE = max number of LE shorting rods
Imax = the column current at the max terminal voltage
Ile = LE column current
Ihe = HE column current
Iprb = corona probe current
Itotal = total charging current
VtMax = the maximum terminal voltage
Vt = the desired terminal voltage

Ile = (SRmaxLE / (SRmaxLE - SRle)) * (Imax/VtMax) * Vt
Ihe = (SRmaxHE / (SRmaxHE - SRhe)) * (Imax/VtMax) * Vt
Itotal = Ile + Ihe + Iprb

Corona Probe Position

A table containing corona probe positions and terminal voltages is created for the usual tank pressure. The corona probe position is determined by doing a table lookup in this table.

Corona Probe Quiescent Current

This does nothing.

Manual page revision

$Id: scale_formulae.3,v 1.1 2002/04/07 19:18:06 kitchen Exp $

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