BSRT CALIBRATION MDSUMMARY

LSWG #6-15/09/2015

BSRT TEAM

LHC MD475: Calibration of the BSRT created by Enrico Bravin accepted

Time required (hours): 6

Assigned time slots:•26 August 2015 13:00 – 26 August 2015 16:00

Merit:The BSRT beam size measurement relies on the knowledge of several calibration and correction parameters. These parameters can only be inferred from dedicated beam based measurements. This MD covers the beam manipulations needed to calculate the BSRT calibration parameters.

Description:Inject few small emittance indiv bunches, blow up some bunches with the ADT in order to obtain bunches with emittances covering the largest possible range. Perform orbit bumps around the undulators in IR4 and perform measurement with several telescope settings. Perform wire scan measurements for each bump step. Dump and inject the beams again, ramp to 6.5TeV and perform the same procedure described above.

Beam energies:•Injection•Flat top

Optics: Injection, flat-top, squeezed

Orbit change: Yes

What else should be changed: Need to use the ADT to blow up the beams

Beam parametersBunch intensity (1011 ppb): 1.1Number of bunches: about 10Transverse emittance (μm): large range 1 to 10Bunch length: 1

LHC MD475: Calibration of the BSRT created by Enrico Bravin accepted

Time required (hours): 6

Assigned time slots:•26 August 2015 13:00 – 26 August 2015 16:00

Merit:The BSRT beam size measurement relies on the knowledge of several calibration and correction parameters. These parameters can only be inferred from dedicated beam based measurements. This MD covers the beam manipulations needed to calculate the BSRT calibration parameters.

Description:Inject few small emittance indiv bunches, blow up some bunches with the ADT in order to obtain bunches with emittances covering the largest possible range. Perform orbit bumps around the undulators in IR4 and perform measurement with several telescope settings. Perform wire scan measurements for each bump step. Dump and inject the beams again, ramp to 6.5TeV and perform the same procedure described above.

Beam energies:•Injection•Flat top

Optics: Injection, flat-top, squeezed

Orbit change: Yes

What else should be changed: Need to use the ADT to blow up the beams

Beam parametersBunch intensity (1011 ppb): 1.1Number of bunches: about 10Transverse emittance (μm): large range 1 to 10Bunch length: 1

LHC MD475: Calibration of the BSRT created by Enrico Bravin accepted

Time required (hours): 6

Assigned time slots:•26 August 2015 13:00 – 26 August 2015 16:00

Merit:The BSRT beam size measurement relies on the knowledge of several calibration and correction parameters. These parameters can only be inferred from dedicated beam based measurements. This MD covers the beam manipulations needed to calculate the BSRT calibration parameters.

Description:Inject few small emittance indiv bunches, blow up some bunches with the ADT in order to obtain bunches with emittances covering the largest possible range. Perform orbit bumps around the undulators in IR4 and perform measurement with several telescope settings. Perform wire scan measurements for each bump step. Dump and inject the beams again, ramp to 6.5TeV and perform the same procedure described above.

Beam energies:•Injection•Flat top

Optics: Injection, flat-top, squeezed

Orbit change: Yes

What else should be changed: Need to use the ADT to blow up the beams

Beam parametersBunch intensity (1011 ppb): 1.1Number of bunches: about 10Transverse emittance (μm): large range 1 to 10Bunch length: 1

MD Philosophy Along the MD continuous emittance measurement with the reference device: WS

=> Have the “real” emittance under control

Change the BSRT telescope configuration (move the lens and move the camera)At each configuration:

Diagonal orbit bumps (SR source “the beam” is moved by a known quantity measured by the BPMs)=> Observing the shift of the light beam on the Camera, obtain the optical magnification

Correct the BSRT measurement by the magnification

Deduce the BSRT optical resolution (correction to be applied) to measure the same emittance as the WS

Identify the telescope configuration that yields the highest resolution (Lower correction to be applied)

Parasitically Bumps in IR4 includes the WS as well => use the bump amplitude to crosscheck the WS scaling factor

WS PARASITIC STUDIES(however necessary for the calibration)

SPREAD Before

SPREAD After

SPREAD Before

SPREAD After

Slope : 1.0272.7%

Slope : 0.9891.01%

SCALING FACTOR TO CORRECT WS MEASUREMENTS

WS BEFORE SCALINGWS AFTER SCALINGLINEAR FIT USED FOR BSRT CALIBRATION (as real emittance)

WS BEFORE SCALINGWS AFTER SCALINGLINEAR FIT USED FOR BSRT CALIBRATION (as real emittance)

WS BEFORE SCALINGWS AFTER SCALINGLINEAR FIT USED FOR BSRT CALIBRATION (as real emittance)

WS BEFORE SCALINGWS AFTER SCALINGLINEAR FIT USED FOR BSRT CALIBRATION (as real emittance)

BSRT STUDIES

LENS POSITION

CAMERA POSITION

ORBIT BUMPS

OLD WORKING POINT

OLD WORKING POINT

Necessary Validation

B1 HProfiles from WS validation during

high beta with pilots

B1 VProfiles from WS validation during

high beta with pilots

B2 HProfiles from WS validation during

high beta with pilots

SATURATED

B2 VProfiles from WS validation during

high beta with pilots

SATURATED