1. Beam instrumentation for HIE-ISOLDE
Sergey Sadovich
on behalf of BE-BI group and HIE-ISOLDE collaboration
BI/TB – Thursday 2 Nov 2017

2. Agenda Current status Instruments: performance and issues
Planned activities for end beginning 2018

3. Current status

4. HIE-ISOLDE – stage 2A Beam diagnostic tasks:
to 9.3 MeV/u for beams with A/q = 4.5
to 14.3 MeV/u for beams with A/q = 2.5
Experimental targets
Beam diagnostic tasks:
Required by users and OP:
Max current of RIB
Intensity (transmission)
Position of the beam
Transverse profile
Transverse emittance
Absolute energy measurement (0.5% resolution)
Longitudinal profile
from 2.85 MeV/u

5. HIE ISOLDE layout – Beam Instrumentation
5 “short” and 13 “long” diagnostic boxes are installed
Instrumentation:
All boxes have:
Faraday Cup
Scanning Slit
Collimator blade
Additional devices:
Silicon Detectors (x5)
Stripping Foils (x4)
Silicon Telescope (x1)
USER’S Faraday Cup (x2 per line)
Note:
Current configuration is operational
Some work is still to be performed this year and beginning of 2018
XT02.BDB.1100
XT01.BDB.0900
XT03.BDB.0900
XT02.BDB.0630
XT01.BDB.0400
XT02.BDB.0400
XT03.BDB.0400
XLN2.BDB.0300
XLN3.BDB.0300
XLN4.BDB.0300
XLN5.BDB.0300
XT00.BDB.0700
XT00.BDB.1050
XT00.BDB.1300
XT00.BDB.1600
XT00.BDB.1900
XT00.BDB.2200
XT00.BDB.2500

6. Beam Diagnostic Box “Short” and “Long” type Collimators Scanning slit
Stripping foils
Faraday Cup
Si. detector
Collimators
beam
Si telescope
Vacuum pump
“Short” and “Long” type

7. Back in 2014… original layout
“Several” differences from the original spec
In short:
Short/long DB
6 type of instruments
3 different type of Silicon Detectors
Different holders for SD
Different holders for stripping foils
Different actuators for collimator slits
Every DB starts to be unique

8. BI-HIE ISOLDE web page Information about Instruments Diagnostic Boxes
Information about
Instruments
Diagnostic Boxes
Manual
Cabling

9. Instruments: performance and issues

10. Faraday Cups (direct charge collection):
Short and long Faraday Cups schematic design
*Short FC gives ~10% higher current (with repeller HV up to -300V) than Long FC
Installation two FC in one box is forseen

11. FC and Scanning slit (profile measurement)

12. FC and Scanning slit (profile measurement)
The beam reading in the FC is altered when the beam is off-centered / too large and hits repeller
Since 2017 available in OP application and actively used

13. FC and 2 Scanning slits (transverse emittance)
This measurement was planning but is postponed

14. Silicon detectors
Absolute energy measurement of the beam was proved: roughly measurement using energy output and fine correction using timing output.
Using TOF for energy measurement/phasing cavities was proved.
Time of flight measurement using two detectors (annular and entire) at the same time requires too much time for tuning the beam (position and intensity) and is not sufficient. Two silicon detectors can be used alternately. However holder for SD in XT00.BDB.1050 is modified and can be used with SD in XT00.BDB simultaneously with partial overlap.
Works well as sensitive faraday cup for RIB (single particle detection). Different applications
XLN2.BDB.0300
XT00.BDB.1300
XT00.BDB.1900
XT00.BDB.1050
XT01.BDB.0400
XT02.BDB.0400
XT03.BDB.0400

15. Cavity phasing

16. Cavity phasing using TOF information
Change in energy when the phase of a SRF cavity is changed
Phase [deg]
dE [bin]
-150
-100
-50 50
100
150
3800
3700
3600
3500
3400
3300
Change in TOF when the phase of a SRF cavity is changed
Phase [deg]
dTOF [ns]
-150
-100
-50 50
100
150 25 20 15 10 5
This method is faster than using the information on the energy since beam currents can be higher (i.e. less saturation constrains) and all the events can be used to build up the statistics in multi-ion beams

17. Relative energy measurements using dipole
B [T]
I / IMAX
Dipole scans for beams with different energies
1 mm vertical slits
All quads and steerers off
Silicon detector
Energy measurements using the first dipole magnet of the XT01 line:
Vertical slits (1 mm) were inserted before and after the dipole to select ions in the beam axis
Quads and steerers were turned off
The silicon detector in XT was used to measure the beam rates for different settings of the dipole

18. Energy Measurements Using TOF
XT Si detector
7.76 m
XT Si detector
time [ns]
N / NMAX
Bunch time structure for beams with different energies measured at XT Si detector
time [ns]
N / NMAX
Bunch time structure for beams with different energies measured at XT Si detector
The TOF system uses the time information provided by two silicon detectors separated 7.76 m from each other
Energy changes smaller than 0.5 % could be easily resolved
Bunch structure in second Si detector has partially degraded

19. Energy measurement: summary
3 different techniques were used for beam energy measurement (energy output of SD, (spectroscopy), dipole scan and time-of-flight measurements)
After cross-calibration all methods give consistent results
Changes of energy less than 0.5% could be resolved

20. Silicon detectors
Two more SD will (?) be installed in XT and XT
XLN2.BDB.0300
XT00.BDB.1300
XT00.BDB.1900
XT00.BDB.1050
XT01.BDB.0400
XT02.BDB.0400
XT03.BDB.0400
Sensitive FC:
“there is nothing more permanent than temporary…”
unknown author

21. Degradation of SD
Degradation (not critical for relative measurement, can affect final measurements)
SD in XLN2 should be changed.

22. Energy measurement: Pulse Height Defect
Cocktail of beams (EBIS and Xe from GPS target) sent to the XT silicon detector
PHD is visible for heavy ions – time of flight technique should be used for energy measurement
# Counts
Energy bin #
Energy spectrum for a beam with A/q = 4.0 and REX energy
132Xe33+
40Ar10+
20Ne5+
16O4+
4He1+
12C3+
XT deviation from linearity
Mass Number (A)
Ebin# / A
Mass Number (A)
Ebin# / A
Deviation from linearity as a function of mass number
XT deviation from linearity
Mass Number (A)
Ebin# / A

23. Stripping foils
Stripping foils have life time…

24. FESA and SW HW layer FESA layer VME board HREXDBOB HREXDBOX_BI
Control movement of devices
Faraday Cup acquisition
FC HV control
Beam profile scan
New release at the end of 2016y
HREXDBOB
HREXDBOX_BI
HREXDBOX_FC
HREXDBOX_SL
Digitizer CAEN V1724
Energy measurement using Silicon Detector
HREXDIGI
TDC Acqiris TC890
Energy measurement using Time Of Flight technique using Silicon Detector
HREXTOF
Devices in BDB:
Scanning slit
Faraday cup
Collimator slit
Stripping foil
Silicon detector
ISEG HV power supply
High Voltage control for Silicon Detector
BHVVDS24

25. FESA
HREXDBOB
Full control of the custom made VME card:
Stepping motors control
Acquisition of the FC
Control of custom made preamplifier for FC
HV control of the FC
Interlocks in VME to avoid collision of instruments
Interlock system on FESA level to avoid collision of instruments
Expert application
HREXDBOX_BI, HREXDBOX_FC, HREXDBOX_SL
Functionality and interface necessary for the specific type of the instrument
HREXDIGI
Control of CAEN V1724 digitizer
Energy measurement
Protection of the SD from damage by intense beam
Silicon telescope
HREXTOF
Time-of-flight measurements using AGILENT time to digital converter
BHVVDS24
Control of ISEG HV power supply used for SD
Several modifications will be done to improve performance (not critical bugs).
For all classes expert applications are available

26. Available infrastructure
TDC has 6 channels (5 SD) and used mostly for countrate (counts per second). Modification of FESA class HREXDIGI will be done to free channels of TDC.
Two Digitizer are available (8 channels each) (6 for all possible ST, 7 for all possible SD)
Two HV ISEG cards are available (8 channels each) .
Additional instruments (of the same type) can be added, but for new DB installation additional equipment is required.

27. Planned activities
Temporary installation of DB after ISS magnet December 2017 (scanning slit and FC should be available)
Installation CM4 – early 2018:
Movement of DB – connection / disconnection
Work on instruments/update SW can be done
(?) Silicon telescopes installation (XT01 and XT02)
(?) Silicon detectors installation (XT02 and XT03)

28. Summary
At the end 2017 all beam diagnostics (boxes and instruments) at HIE ISOLDE are installed and functional:
Software control system is available for all diagnostic devices (FESA and expert tools).
All the systems have been successfully commissioned and met specifications.
Physics campaign since July 2017… still going well.
Several improvements are foreseen for end 2017 – beginning 2018

29. Acknowledgements
This presentation includes work and contribution from many CERN colleagues, in particular William Andreazza, Stephane Bart Pedersen, Enrico Bravin, Stephane Burger, Esteban Cantero, Michel Duraffourg, Martino Ferrari, Gerrit Jan Focker, Alberto Rodriguez, Jean Tassan-Viol.