This is a draft for documenting the BPTX monitoring system

This page serves the purpose of collecting information over time, to build the documentation for the BPTX monitoring system.

General

The BPTX system, short for Beam Pick-up Timing system for Experiments, is developed to measure timing of the two beams in the LHC by acquiring the analog signal from the corresponding pick-ups (sensors) and process it. The system detects wrong positions of single bunches and a possible drift of the Orbit clock with respect to each beam. Furthermore, it contains a visualization tool, to represent the data in a human readable way, as well as pushing the data for longtime storage.

Production Setup

The oscilloscopes used in the BPTX production setup is two identical Agilent DSO9254A running Windows XP. Both scopes are located underground at CMS P5 USC in a 19" rack labeled TTC S1E01 and can be accessed from both sides. The tables below shows the input and output setup for the two oscilloscopes.

Description (Master)	Signal	Input / Output
Orbit 1 for synchronization and timing	Orbit 1	Input, Channel 1
Orbit 2 for timing measurement	Orbit 2	Input, Channel 2
BPTX 1 for timing measurement	BPTX 1	Input, Channel 3
BPTX 2 for timing measurement	BPTX 2	Input, Channel 4
Synchronization of master and slave trigger	Trigger	Output, Trigger Out

Description (Slave)	Signal	Input / Output
Orbit 1 for synchronization and timing measurement	Orbit 1	Input, Channel 1
BC Main for timing measurement	BC Main	Input, Channel 2
BPTX 1 for timing measurement	10MHz Clock	Input, 10MHz
BPTX 2 for timing measurement	Trigger	Input, AUX

The BPTX channels are terminated with 1 MΩ . This is crucial to prevent reflections in the signal and interference with other systems dependent on the signal. Due to the internal 1 MΩ an additional external 50 Ω resistor is added to avoid additional reflections in the transmission lines. All these terminations are done on the Master scope.

Networking

Both of the oscilloscopes are connected to the CMS-Cluster machine "srv-s2b16-28-01". This machine is located inside the .cms network and can be accessed via x2go or .cmsusr. from the .cern.ch network. Both scopes are running a VNC server, and can be used for both monitoring as well as control. To access these, use the hostname and the IP adresses listed below.

Unit	IP
srv-s2b16-28-01	10.176.6.22
bptxmon-master	192.168.100.2
bptxmon-slave	192.168.99.2

Monitoring Software

The BPTX monitoring software is developed in C++ and is compiled in CentOS 7. This was then implemented to the CMS XDAQ framework, and is running by the XML-file of the project. This project can be accessed via the SVN repository (SETT IN REPO HER)... The programmed software connects via Ethernet sockets to the two oscilloscopes and starts to configure those. First the setup method will stop and reset both scopes, then the channel configuration will be started. The start configuration of both BPTX scopes can be seen in the table below.

Parameter	Value	Name in config*
Coupling	DC	master_ch3_CouplingAndTermination
Termination	1MΩ	master_ch3_CouplingAndTermination
Bandwidth Limit	off	master_ch3_BandwidthLimit
offset	0 V	master_ch3_offset
Scale	1 V/div	master_ch3_Scale
Skew	0 s	master_ch3_skew

Start configuration for the BPTX channels * For BPTX 1 use "ch3" and for BPTX 2 use "ch4" in the config name.

Parameter	Value	Name in config*
Coupling	DC	master_ch1_CouplingAndTermination
Termination	50 Ω	master_ch1_CouplingAndTermination
Bandwidth Limit	off	master_ch1_BandwidthLimit
offset	0 V	master_ch1_offset
Scale	300 mV/div	master_ch1_Scale
Skew Orbit 1	0 s	master_ch1_skew
Skew Orbit 2	30 μs	master_ch2_skew

Start configuration for Orbit input channels * For Orbit 1 use "ch1" and for Orbit 2 use "ch2"

Parameter	Value	Name in config*
Coupling	DC	master_ch2_CouplingAndTermination
Termination	50 Ω	master_ch2_CouplingAndTermination
Bandwidth Limit	off	master_ch2_BandwidthLimit
offset	0 V	master_ch2_offset
Scale	200 mV/div	master_ch2_Scale
Skew	0 s	master_ch2_skew

Start configuration for BC main

Further the Master and Slave is configured with the following settings. Note the 8 times averaging on the master and the zero averaging at the Slave. It's impossible to average due to the fact that BC-main can be generated without phase lock on the signal which is triggered. This ensures reduced noise on the signals which are always phase locked and in case of internal generation of the BC-main, the capability to analysis BC-main independent signals from the software.

Parameter	Value	Name in config*
Recording length	10E6 sample	master_recordingLength
Sample rate	10E10 sample/s	master_sampleRate
Average Mode	on	master_averagingMode
Average count	8	master_avgCount
Acquire mode	RTIMe (real time)	master_acquireMode

Skriv nå her MASTER

Parameter	Value	Name in config*
Recording length	10E6 sample	slave_recordingLength
Sample rate	10E10 sample/s	slave_sampleRate
Average Mode	off	slave_averagingMode
Average count	1	slave_avgCount
Acquire mode	RTIMe (real time)	slave_acquireMode

Skriv nå her SLAVE

Web Interface

Write a quick guide and a overview of the web interface and its framework

SVN repository for the website

-- NicholasSkram - 2017-05-10