1. Fast BLM acquisition system
Bernd Dehning
CERN BE/BI
Plots are taken from:
Tobias Baer, Henrik Janson, Maria Hempel, Elena Castro, Christoph Kurfuerst
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Fast BLM acquisition system, B.Dehning

2. Fast BLM acquisition system, B.Dehning
Content
The diamond detector
CERN installations
Specification
Signal versus time
Arrival time histogram
Acquisition systems
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Fast BLM acquisition system, B.Dehning

3. Fast BLM acquisition system, B.Dehning
Beam loss sensors
IC Diamond PM (ACEM)
Response time: ns < ns ns
Pulse duration: 100 us ns few ns
Dynamic orders orders orders
Radiation tolerance MGy several 10 MGy kGy
Volume l cm cm3
Signal degradation factor 10
50 ns bunch spacing
Risetime: 2.34ns Falltime: 10.34ns Amplitude: 397mV Background noise: 9.9mV Temporal width: 6.06ns
MGy
Leakage current
CVD detector superior in terms of response time,
pulse duration and dynamic range
Often it is the case that the acquisition chain is limited by the sensor; diamond sensor (CVD) exploitation requires high performance electronics
Max 20 pA
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Fast BLM acquisition system, B.Dehning

4. BLMED Installation Overview
Acc IP
Position
Detector
LHC 2
BLMED.04L2.B1I10_TCTVB.4L2
CIVIDEC 3
BLMED.06L3.B1I10_TCP.6L3.B1
BLMED.06R3.B2E10_TCP.6R3.B2 6
BLMED.04L6.B2I10_TCSG.4L6.B2
BLMED.04R6.B1E10_TCSG.4R6.B1 7
BLMED.06L7.B1E10_TCHSS.6L7
BLMED.06R7.B2I10_TCHSS.6R7 8
BLMED.04R8.B2C10_TCTVB.4R8
SPS 4
MSE 41876
TPSG 61773
BLMED.04L2.B1C10_TDI.4L2.B1
BCM1F4LHC
BLMED.04R8.B2C10_TDI.4R8.B2
BLMED.05L4.B1C10_BGI
BLMED.05R4.B2C10_BGI 5
BLMED.04L5.B1I10_TCTVA.4L5.B1
BLMED.04R5.B2I10_TCTVA.4R5.B2
Following detectors are foreseen to be installed during LS1 and LS2:
1 detector for Fast Servo spill in the SPS TT20 (LS1)
1 detector for HiLumi in the LHC (LS1)
8 detectors for Booster dump (LS2)
10 (12) Detectors for PS (LS2)
Fast BLM acquisition system, B.Dehning
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5. Location of Diamond Detectors at CERN Accelerators
Status and Application of Diamond BLMs; B.Dehning 5

6. Location of Diamond Detectors at CERN Accelerators
Status and Application of Diamond BLMs; B.Dehning 6

7. Optical diamond detector (BCM1F4LHC)
All detector signals arrive at the same position
Easy access of data acquisition system
Lower dynamic range
Fast BLM acquisition system, B.Dehning
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8. Tunnel set ups CIVIDEC system CMS DESY/Zeuten system Optical fibre
Status and Application of Diamond BLMs; B.Dehning 8

9. Technical Specification of Fast DAQ
Analogue bandwidth
DC – 500 MHz
V In min
10 mVpp
V In max
10 Vpp
 7V RMS
Acquisition:
Resolution
8/10/12 bit
 Solution specific
Sampling rate
1Gs/s (2.5ns – 1ns)
Sampling length
10ms 1Gs/s per channel
 selectable
8 bit
10k – 1G (points) = 240kbit – 24Gbit (4Gbyte)
4 Channels
12 bit
10k – 1G (points) = 360kbit – 36Gbit (
3 Channels
Trigger system:
Signal input
Edge (Threshold set with 10bit DAC)
Min. 5mV
Ext. Input 2
Edge
TTL signal
Software trigger
On event
via data transmission
Histogram:
ns (57024 bins)
 Bunch length / 16
Trigger threshold
min. 5mV
 10 bit DAC
Counter
20-24 bit per bin
Update rate 1s
Scaler:
20-24 bit
Controller or FPGA software:
Source code
User accessible for modifications
Preferable
Drivers & Control software
Driver
Open source Linux  
Control
Linux
Fast BLM acquisition system, B.Dehning
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10. Fast BLM acquisition system, B.Dehning
Specification PS
SPS
LHC
Dynamic [orders of magnitude ]
5-6
Sampling frequency [GS/s] 1
Number of value to be stored per channel
2E6
22E6
1E9
Synchronisation with machine events y
Sampling frequency, bandwidth
500 MHz analogue bandwidth relates to a rise time of 0.7 ns (10 – 90%)
Rise time observation 2.3 ns, limited by 1GHz sampling frequency and cable, rise time contribution from analogue part of acquisition almost negligible
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11. Fast BLM acquisition system, B.Dehning
Signal versus time acquisitions
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Fast BLM acquisition system, B.Dehning

12. Diamond Measurement 4 batches
4·36 bunches
LHC injection gap
SPS injection gaps
36 bunches

13. Diamond Measurement 1 batch
36 bunches
All bunches contribute to the beam losses, as expected for a macro particle interaction.
50ns spacing between bunches

14. Event Sequence Start of B1 losses in IR7.
Fire MKD.B2
No IR5 bb kick
Losses in IR7
IR1
IR6
IR7
IR5
IR3
IR4
IR2
IR8
1/8
3/8
8/8 turns
Pacman structure of beam losses.

15. Event Sequence
Losses due to uncaptured beam in abort gap during MKD rise time observable in IR7.
No IR2, IR1, IR8 bb kick
Fire MKD.B2
Dump losses
No IR5 bb kick
Losses in IR7
IR1
IR6
IR7
IR5
IR3
IR8
IR4
IR2
1/8
3/8
6/8
8/8

16. Event Sequence
Losses due to uncaptured beam in abort gap during MKD.B1 rise time observable in IR7.
No IR2, IR1, IR8 bb kick
Fire MKD.B2
B2 dumped
Fire MKD.B1
Dump losses
No IR5 bb kick
Losses in IR7
Dump losses
IR1
IR6
IR7
IR5
IR3
IR8
IR4
IR2
1/8
3/8
6/8
8/8
10/8

17. Bucket counting on consecutive turns
MKI UFO dump which illustrates the timing. The data is acquired by the IR7 diamond BLM for B1. The yellow line shows the losses during the last turn incl. the spike due to the MKD rise time. As reference in red the losses around the abort gap in the previous turn. One can see that the losses which are observable in IP7 occur about 875ns after the beginning of the abort gap and about 1.8us after the last bunch.
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18. CNGS - SPS extracted pulse
10 us
5 ns
SPS 5 ns bunch structure measureable with 150 m of Cu cable
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19. Ring BLM Measurements Spatial loss profile
UFO Location: BSRT.05L4.B2 Temporal loss profile B1 B2
UFO location
Diamond BLM
B2 direction
On the following slides: Measurements with BMLED.06R7.B2I10_TCHSS.6R7.B2. 40dB signal amplification.

20. Diamond Measurement Overview
1 turn
Losses due to beam dump

21. Diamond Measurement 1 turn
Beam abort gap
Losses due to beam dump
4·36 bunches
2·36 bunches

22. Bunch by bunch tune measurement
The data was taken during the EOF test of the beam-beam MD on , where B2 was dumped first, which led to a coherent oscillation of B1 due to the missing LRBB deflections.
The frequency resolution is limited, because the losses were acquired for only ~200 turns.
The duration of recording (1s) determines
the required memory size
(IEC team, T. Pieloni)
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23. Fast BLM acquisition system, B.Dehning
Arrival time histogram referenced to revolution period
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Fast BLM acquisition system, B.Dehning

24. HERA Scraping Beam with Wires
Inner wire
wire ~ 4 sig
begin fill
HERA
Bunch spacing 96 ns
Samples taken every 21 ns
No coasting beam halo
3 samples with zero intensity (left, top)
Partially coasting halo
Inter bunch samples measure intensity (left, middle)
Only coasting halo
(left bottom)
Strong coasting component at begin of fill (centre top)
Bunched halo only minutes later (centre, middle)
With retracted wire diffusion of coasting component into cleaned area (centre bottom), SPS
Effect caused by RF system noise, faulty amplifier
wire ~ 4 sig
Outer wire
4 min later
Halo Intensity
wire ~ 6 sig
Outer wire
wire retracted
LMC
B.Dehning 24

25. Arrival time histogram IP5 CMS system
With 25 ns spacing and debris from
the IP spacing reduced to 12.5 s
Allows details of bunch spacing
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Fast BLM acquisition system, B.Dehning

26. Arrival time histogram with simulated and CVD signal
Bunch period
signal at input of
acquisition system
CVD detector
signal at input
acquisition system
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Fast BLM acquisition system, B.Dehning

27. Arrival time histogram during ramp
Bunch spacing reduced due to cross talk
Sub 25 ns resolution required
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28. Arrival time histogram - Coasting beam and instabilities
By continues updated display observation of all bunches possible
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Fast BLM acquisition system, B.Dehning

29. Arrival time histogram with the CMS system
IP2, 5 and 8 losses from tails and experiment
IP4 losses from core of beam
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30. Arrival time histogram & injection losses
Before injection
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31. Arrival time histogram & injection losses
After injection
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32. Arrival time histogram & injection losses
later after injection
Clean injection check should also be possible at the PS and SPS
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33. New Diamond Detector Cascade Schemes
tunnel
side tunnel
Detector signal split in two signal paths (direct and 40dB amplified)
Monitoring of complete dynamic range possible
No need to access tunnel to exchange amplifier for different users
Fast BLM acquisition system, B.Dehning
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34. System propositions 8 - 10 - 12 bit solution possible
3 – 4 channel per system needed
Splitter and/or optical input
can be separated form DAQ
In case of a modular system more than 4 channel possible
Parallel processing of histogram and loss versus time mode preferable
Fast BLM acquisition system, B.Dehning
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35. System Comparison Fast BLM acquisition system, B.Dehning
Important Technical Aspects
BI/BL Man power
Dead line
Comments
Storage per Ch
Resolution
Rate
FPGA
CPU
Production
BI/BL
8 MByte
10 bit
1 GSPS
Yes No
Tender for FMC needed
Tender 1
1.25 GByte
1.25 GSPS
Offer is without chassis and CPU
Tender 2
2 GByte
12 bit
1.6 GSPS
Modular system, Onsight consualtion
Tender 3
4 GByte
8 bit
QT GUI exist, Future option 12 bit
Tender 4
1.5 GByte
Completely new development
Tender 5
250 MByte
Future option 8 Gbyte
OASIS
250kbyte
8 bit
1-2 GSPS No
Yes
The FPGA can not be programmed
Fast BLM acquisition system, B.Dehning
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36. Fast BLM acquisition system, B.Dehning
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Fast BLM acquisition system, B.Dehning

37. Fast BLM acquisition system, B.Dehning
CMS system
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Fast BLM acquisition system, B.Dehning

38. Fast BLM acquisition system, B.Dehning
IP4 abort gap recording
Cross talk from other beam dominant
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Fast BLM acquisition system, B.Dehning

39. Fast BLM acquisition system, B.Dehning
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Fast BLM acquisition system, B.Dehning