this draft presentation shows a comparison between the measured projection

This draft presentation shows a comparison between the measured projectionof the wire and the theoretical projection of the wire. The measured projectionof the wire has been performed using the PS laser calibration system.

The measurement has been performed for the scan speeds of 10 and 15 m/sfor the IN and OUT movements. The measurements has been repeated 3 times for each movement and speed.

This study is based in the following assumptions and parameters:- the distance from the fork axis to the beam axis (OBF) is 100,44 mm- the total angle of the fork travel (Th) is 136 degrees- the angle between the fort at IN position and the projection axis (Th0) is 0- the positive direction of the fork rotation is defined from the IN to the OUT- the distance between the laser and the beam (OL) is 0- the distance from the axis of the fork to the wire (FL) is 164 mm- the potentiometer value at IN position (potIN) is 41215 bits- the potentiometer value at OUT position potOUT) is 24345 bits- the total angle travelled by the motor is 180 degrees

see next slide for more details

Review of the New CERN Fast WirescannerJuan Herranz 18.04.20139th DITANET Topical Workshop on Non-Invasive Beam Size Measurements for High Brightness Proton and Heavy Ion Accelerators

PhotodiodeLaser DisplacerBeam

expender DisplacerScanner

+/- 50 mm Calibration table

Minimization strategies - Calibration

time

diod

e sig

nal

IN OUT

Thanks to Jonathan Emery

ThOFB

Beam axis (center of the tank)

tank wall

fork axis

projection axis

FL

Th0Laser axis

OL

IN

OUT

Scanner configuration

shows the calibration region location respect to the total projection of the fork travel

projection~ 288.3 mm

calibration region100 mm

motor position (bits)

wire

pro

jecti

on (m

m)

Scanner configuration

-50

0

50

-100

250

Scanner configuration

The following plots show the comparison between the wire projected positionrecorded with the laser calibrations system and the theoretical projection of thewire based in the kinematic chain of the scanner.

In principle the differences between both projections are due to the deformationson the mechanical parts of the system and on the carbon wire during the movement.

In order to have a more realistic comparison, most of the parameters used in this analysishave to be verified with the scanner used in the calibration system .For example the assumption that the angle between the fork of the scanner at IN position and the projection plane (Th0) is 0 is maybe not fully right.

The following plots are equivalent to the previous plots with the difference that the the value Th0 is set to 3 degrees.

calibration region

calibration region

PART 2

Bits

Volts

G1 @ 15 m/s

OUT

IN

OUTOffset between IN and OUT

0.25 V ~ 40 um

IN

OUT

After fixing electrical cable !

PART 3

??

beating phenomena