1. Diagnostics @ThomX Beam Loss Monitors (BLM)
I. Chaikovska, V. Kubytskyi

2. Physics principle (FBLM)
Vacuum
Secondary electron
Chamber Wall
Upstream PMT
Downstream PMT
Fiber
Cherenkov light
FBLM is based on fibers installed alongside the whole accelerator.
Optical fiber attached to the vacuum chamber.
Electromagnetic shower generated when the main beam hits the vacuum chamber or any obstacle.
Cherenkov radiation produced in the optical fiber by the electromagnetic shower.
The fiber ends are coupled to the PMTs.
Cherenkov light converted to an electrical signal containing the information about the position and intensity of the beam losses.

3. Physics principle (FBLM)
Vacuum
Secondary electron
Chamber Wall
Upstream PMT
Downstream PMT
Fiber
Cherenkov light
FBLM is based on fibers installed alongside the whole accelerator.
For a given loss, the response may vary due to
the distance of the loss from the fiber
the direction of the scattered radiation
the amount of material between the loss and the fiber (beam hardware)
Fiber should be installed so that the fiber path length and the beam path are about equal.

4. Physics principle (FBLM calibration)
The calibration of the FBLM can be done by several techniques:
To use the beam loss signal produced by inserting a known device such as the vacuum valve, scrappers, screen, etc. as the reference
First negative edge of this signal from the fiber marks the location of the inserted obstruction
Tests have indicated that the speed of light in the fiber is about 0.63c (0.19 m/ns).
Knowing the speed of light in the fiber, one can calibrate the oscilloscope display to the real distance along the accelerator.
Calibration gives that every meter along the accelerator is 8.6 ns on the oscilloscope.

5. Physics principle (Scintillator)
FBLM is based on fibers installed alongside the whole accelerator.
In addition to the BLM we have also developed the compact BLM based on the CsI(Tl) scintillator coupled to the PMT. The system consists of the crystal CsI(Tl), which is attached to the PMT
CsI 2
10 mm
8 mm
PMT 2
Scintillator assemblies are attached to the vacuum chamber.
Electromagnetic shower generated when the main beam hits the vacuum chamber or any obstacle.
Scintillation radiation produced in the CsI(Tl) by the passage of a charge particles
Scintillation light is converted to an electrical signal containing the information about intensity of the beam losses.

6. Fibers and Detection system
Hamamatsu Photo sensor module (PMT)
H10721 (High Voltage power supply included)
Power Supply +5V, Gain Control : V
FC adaptor for Optical Fiber
Fibers are attached directly to PMT
Compact PMT for Diagnostics
Fiber HPCS600UVT
Fiber
Core 
600 μm ± 2%
Cladding 
630 μm ± 3%
Coating 
Buffer 
950 μm ± 5%
Clad material
Hardclad polymer
Buffer material
Tefzel®
350 nm
< 1.0 dB/m
Numerical Aperture
0.37 ± 0.02
@PHIL
Thanks to P. Cornebise

7. According to the drawing
FBLM PHIL
Calibration: typical signals
YAG1
YAG2
YAG3
Sapphire
PMT Gain = 1 V (~ 2*106)
ICT1 = 83 pC
FBLM
According to the drawing
YAG1-Sapphire
0.96 m
0.87 m
Sapphire-YAG2
0.2 m
0.28 m
YAG2-YAG3
4.22 m
4.11 m
Unlike other screens for the screen YAG1 we observed two separate peaks.

8. FBLM PHIL
YAG 1
Sapphire
YAG 2
YAG 3

9. Layout FBLM @ThomX 1 fiber on LI, 1 fiber on TL and 1 fiber on EL.
4 fibers cover the whole SR.
In SR, the FBLM has been installed in 4 sections so that losses from different turns can be separated.
FBLM is a “continuous” BLM => requires a special procedure/calibration to retrieve the position of the Beam Losses!

10. Layout
Additional BLM installed at the specific locations (injection/extraction, LI and TL on request…) => provide immediately additional to the FBLM information while the FBLM being calibrated to give a good precision in beam loss locations.
The light yield of the CsI is very high => very sensitive.
Auxiliary/complementary to FBLM.

11. Beam Loss Monitors @ ThomX
Wavecatchers x3
Fiber Beam Loss Monitor (FBLM)
1 fiber for the LINAC, 1 for the TL, 4 for the SR and 1 for the EL.
DAQ: Wavecatcher (Tango DS is ready) Scope for the SR (under the test, remote control) => inside crate Diag 5 and 6
Several beam PHIL
Wavecatcher and its Tango DS have been successfully tested with the FBLM.
Scintillators coupled to the PMT to monitor the local losses (auxiliary/complementary to FBLM tool)
A few assemblies are in preparation to be used during the commissioning and operation regions and can be used on demand).
DAQ: RedPitaya card (Tango DS is ready) => inside crate Diag 5
The assembly has been tested using the scope with the radioactive sources and with the PHIL.
RedPitaya and its DS have been successfully tested.
Scope x1
Red Pitaya x5

12. Beam Loss Monitors @ ThomX: Detection boxes
Detection board
Detection board to be
Thanks to P. Cornebise

13. Rack in preparation Ordered:
3 USB-Wavecatchers, sma cables and connectors.
Assembly by P. Rudnyckyj
Thanks to V. Chaumat

14. Software for the BLM MODEL (Tango data) DS Wavecatcher DS RedPitaya
no DS O-Scope sequence mode
DS BLMmanager
CONTROLLER
(process data)
Init
Subscribe event
Processing:
peaks, calibration, etc.
Write to DS
VIEW
(show data)
Taurus GUI,
Waveforms, control parameters
Synoptic
update
notify
config
Software for the BLM
Model–View–Controller is architectural pattern used for developing user interfaces.
It divides an application into three interconnected parts.

16. Progress status 1/3 Transfert des responsabilités SOLEIL=> LAL
Non applicable
Équipements manquants
All the main equipment is ordered (fibers, PMT, scint… )
To order: scope (if the one under the test will be not quialified),cables patchpanel-rack
Équipements pas encore testés
All the main equipment was tested at PHIL or on the test-bench.
Scope under the test.
The final campaign of the tests will be done on site in the beginning of next year.
Équipements pas encore testé avec le CC (si applicable)
All equipment (Wavecatcher, RedPitaya, Automat Siemens) passed through the CC
Scope and switch AC will be controlled remotely => later, control by Tango
Progrès de l'assemblage des composants (si applicable), intervention entreprise extérieure nécessaire (si applicable)
Rack is in preparation. Assembling of the scintillators are ongoing. Fibers will be cut and connectorized next year. DAQ boxes are ready.
Pas d’entreprises extérieures.

17. Progress status 2/3
Planning d'installation dans l'igloo (identification des étapes pour l'installation, durée, et date d'installation si celle-ci est définie, dépendance avec d'autres sous-systèmes)
Rack is in preparation, will be installed in the beginning of the next year
Fibers and scintillators will be installed after baking of the vacuum system
Dépendances: Câblage, Vide et CC.
Liste des tests de validation sur site.
The list of tests has been written (atrium).
4 days will be dedicated in the beginning of next year.

18. Progress status 3/3
Liste des tests de validation sur site avec le CC (si applicable).
Tests will be scheduled in Spring 2019 (exact days will be defined soon).
Control of the Wavecatchers (ER/CC/RAC.05-ELR.01-WAC.01, ER/CC/RAC.05-ELR.01- WAC.02 , ER/CC/RAC.05-ELR.01-WAC.03).
Control of the RedPitaya (ER/CA/RAC.05/ELR.01/RDP.01, ER/CA/RAC.05/ELR.01/RDP.02, ER/CA/RAC.05/ELR.01/RDP.03).
Control of the automat (ER/CA/RAC.05/API.01).
Control of the scope (ER/DG/RAC.06/OSC.01)
Control of the switch AC (ER/CA/RAC.05-SAC.01)
Interfaces graphiques:
Matlab GUI (was
A new Python (Taurus) GUI is under development
Will be available in Spring 2019.

19. Progress status: Planning
The final check of the whole system (including CS) before installation to be finished before the end of the year (beginning of 2019).
Installation of the FBLM and Scintillators => will be installed after baking of the vacuum system.
Installation of the electronics: rack in crate 5 will be installed in the beginning of 2019
Control system tests with tango (without beam) => will be done in Spring 2019 (~4 days are needed).
BLM tests with beam => ~2 days are needed (injector).
GUI available in the beginning of 2019
The BLM should be completely available in Spring 2019 and should be operational for the Injector commissioning.

20. Maintenance to be planned
Every “shut-down” check the whole system
Possible failures
Broken fiber, PMT, problem with scintillator
DAQ problem

21. BACKUP

22. FBLM PHIL
The fibers were PHIL alongside the vacuum chamber to cover continuously the total length of the photoinjector.
Position calibration was carried out using the YAG screens and Cherenkov monitor.
Fiber 1 (10.92 m)
Fiber 2 (11.04 m)
Dipole
Fiber 1 (15.82 m)
Leetech
YAG 1
YAG 2
Sapphire
YAG 3
YAG 4

23. FBLM PHIL
Beam loss signal generated by the dark current
(60 MV/m). The RF pulse duration is 3 μs which is clearly visible on the waveform.
Beam loss signal (averaged) generated by the Sapphire plate and the YAG-2 screen spaced by m.
One acquired waveform
Averaging over several waveforms
The measured position accuracy allows resolving the beam losses occurring as close as 30 – 40 cm with the 25 m fiber along the vacuum chamber.

24. Scintillator Tests @PHIL
The beam hits the Leetech (end of beamline)
Control Voltage [mV]
500
550
600
650
700
750
800
The beam hits the YAG2 screen
YAG2
τ = 1.5 μS
CsI near YAG2,
Gain of the PMT ~ 5*103
Charge (ICT1-60pC)
DC coupling on oscilloscope 1 MΩ
One acquire waveform for different Control Voltage

25. Physics principle (FBLM)
Downstream time difference
is compressed while upstream
one is expanded.
Upstream PMT is used to
get better FBLM position resolution.
Measurements of the beam loss position can be done by
knowing time difference between the BL signal and reference signal (loss signal produced by inserting a known devices)
having master trigger (beam arrival time).