Beam Condition Monitor Introduction Martin Bieker on behalf of the - - PowerPoint PPT Presentation

Beam Condition Monitor Introduction

Martin Bieker on behalf of the Dortmund BCM group

BCM / WPE introduction meeting— 06.07 .2020

Martin Bieker | BCM Introduction

Motivation

• LHCb Experiment at the LHC
• Sensitive detectors close the high energy LHC

beams

• Susceptible to adverse beam conditions
• Misaligned beams
• Particle showers
• LHCb Vertex Locator with small aperture

2

Martin Bieker | BCM Introduction

Beam Conditions Monitor

• 2 Stations
• BCM-U: Shielding wall in VELO alcove
• BCM-D: Between TT/UT and magnet

3

BCM-U BCM-D

Martin Bieker | BCM Introduction

BCM components

• 8 diamond sensors per station
• 10 mm × 10 mm × 0.5 mm
• Circular support structure
• BCM-U: Aluminium
• BCD-D: Tecapeek
• Read out by charge to frequency

converter (CFC) cards

• Modified LHCb backend board

4

Martin Bieker | BCM Introduction

Front-end electronics

• Current Frequency Converter (CFC) cards
• 8 channels
• Current integrated over 40 μs
• 12bit ADC
• Data transfer
• 2 redundant optical links
• 800 Mbit/s 8b10b encoded data stream
• CRC-32 for error detection

5

Martin Bieker | BCM Introduction

Diamond sensors

• Polycrystalline CVD diamonds
• 8 mm x 8mm Ti/Au metallisation
• Operated @ 200 V bias voltage
• ≅3 fC deposited charge per Sr-90

electron

• < 1 pA dark currents measured in lab

setup

6

Martin Bieker | BCM Introduction

Lab setup

• Single diamond in holder inside light/

EMI shielding box

• Steady state DC current measured

with pico ampere meter

• 13.4 MBq Sr-90 source with variable

distance

7

Martin Bieker | BCM Introduction

Characterisation test beam

• Currently no CCE/CCD measurement

possible

• Measure charge deposited by single

particles (DONNA project WIP)

• Use defined particle flux -> accelerator beam
• Previous iteration of BCM diamonds

characterised at ELBE source

• 20 MeV electron beam
• Beam current: 71 fA to 225 pA

8

[arXiv: 1001.2487]

Backup

Martin Bieker | BCM Introduction

Beam dump logic

10

Current Measurements every 40 μs Short range abort (~1 LHC turn) Long range abort (~14 LHC turn) Sum current per diamond

• ver 32 measurements

Sum diamonds in each station (excluding 2 largest and smallest) Apply threshold Apply threshold for each diamond and frame Threshold passed for two consecutive measurements ? Request beam dump via LHC interface In three neighbouring diamonds?

Martin Bieker | BCM Introduction

Readout during run 1&2

11

Martin Bieker | BCM Introduction

Data generator & input chain

12

CFC data 8b10b encoded Arria V LVDS RX Word Aligner 8b10b decoding word

• rdering

Data stripping FIFO Data CFC data Generator Data Framer FIFO Arria V LVDS RX

800 MHz 80 MHz 40 MHz

Data valid

Bit slip

Frame Encoder

Parallel Loopback Serial Loopback

1b 8b 10b 16b 20b

Bus widths

Martin Bieker | BCM Introduction

Upgrade readout

13 Mini crate Mini crate CFC-U CFC-D PP

D3 rack

MIBAD Card SFP+ SFP+ Mezzanine VELO CIBU PMT PCIe40 Slow Control/ WinCC Full Stream Data

Computing Farm

OM 3/4 12 xOM 2

UX85B

Post Mortem data

Martin Bieker | BCM Introduction

MIBAD Board

• Based on Arria V Starter Kit
• 8 optical links via TerasIC SFP-

HSMC Card

• 4x LVDS “downlink” to CFC cards
• 4x XCVR “uplink” to PCIe40
• Interface to LHC(b) via custom

BCM mezzanine card

14

Machine Interface Beam Abort Decision

Martin Bieker | BCM Introduction

MIBAD architecture

15

Machine Interface (CIBU, BCM_OK, PMT) CFC Input/ Data Generator Uplink to PCIe 40 Frame check&sync Data processing Abort Decision

Data & Monitoring Info Threshold settings, Configuration command, LHC state, etc BCM D BCM U

Control Unit