Commissioning document of the CLAS12 RICH

M. Contalbrigo, V. Kubarovsky, M. Mirazita

June 8, 2016

Abstract

This is an integration to the CLAS12 Commissioning Document describing the Commissioning procedure for the RICH detector.

Contents

1 Executive Summary 2

2 Quality Assurance and System Checkout 2 2.1 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.2 System Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3 Commissioning Without Beam 7 3.1 Special Calibration Procedures . . . . . . . . . . . . . . . . . . . . . . . 7 3.2 Calibration with Cosmic Rays . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3 Commissioning With Beam . . . . . . . . . . . . . . . . . . . . . . . . . 9

4 Contact Persons 10

1 Executive Summary

2 Quality Assurance and System Checkout

2.1 Quality Assurance

RICH Mechanic structure survey (EEL124) Description Check of the relative position of the panels forming the

RICH structure.

The target points installed on the RICH mechanics will be used for the survey. The measured positions must match the ones measured during the assembly test performed at the company.

Special equipments Laser tracker.

Faro-arm.

Softwares  NA
Manpower and time needed  2 days
Information to be saved in database NA

RICH Mirrors (EEL-121) Description Check of the accuracy of the spherical mirror surface with

spot size and Shack-Hartmann measurements.

1. Alignment of the Shack-Hartmann sensor axis.

2. Alignment of the mirror axis with respect to the Shack-Hartmann axis.

3. Alignment of the light source and photocamera for the spot size measurement.

4. Measure the spot size as a function of the distance from the mirror.

5. Wave-front measurement with the Shack-Hartmann sensor at the minimum spot size distance.

6. Shape of the surface with a CMM.

Special equipments Two optical tables.

Shack-Hartmann sensor. Point-like source with LED and optical fiber. CCD photocamera. Remotely controlled motors for the alignment of the system. Coordinate Measuring Machine (CMM)

Softwares Linux software for the remote control of the motors and CCD. Root analysis software for the spot size measurements. Shack-Hartmann reconstruction software.

Manpower and time needed  About 2 days per mirror, based on previous experience
Status  First 4 mirrors tested in June
Information to be saved in database Radius of the mirrors

RICH Mirror alignment (EEL124) Description Verify the relative alignment of the RICH mirrors.

Four mirror systems must be aligned:

1. the frontal planar panel.

2. the lateral planar panel.

3. the bottom planar panel.

4. the spherical panel.

The relative alignment of the mirrors composing each panel will be checked first. Then the panel will be installed in the RICH and its alignment with respect to the others will be checked with optical methods. The position of the panel can be optimized by acting on the adjusting screws of the three attaching points on the RICH structure.

Special equipments Laser tracker.

Faro-arm.

Softwares  NA
Manpower and time needed  one week
Information to be saved in database NA

RICH Aerogel: Catholic University (Washington) Description Check of the optical quality of the aerogel tiles

Special equipments  Spectrophotometer

Manpower and time needed About 1 day per 10 tiles, based on previous experience The work is performed at the Catholic University (Washington).

Status  10 tiles already tested
Information to be saved in database Average transparency and refractive index of the tiles

RICH Aerogel (Ferrara) Description Check of the optical quality of the aerogel on a subsample

of tiles

Special equipments Laser.

CCD photocamera.

Remotely controlled motors to scan the surface of the tile.

Manpower and time needed About 1 day per tile, based on previous experience The work is performed in Ferrara.

Status  Started in October 2015
Information to be saved in database NA

RICH Multi-Anode PMT Description Characterization of the MAPMT Special equipments Laser source.

Flash-ADC.

Remote-controlled motors to scan the MAPMT entrance window.

Status  Completed

Results Measurement of the Single-photon spectrum per each pixel of all the MAPMTs.

Information to be saved in database Gain and single photon resolution of each channel

RICH Electronics: EEL-121 Description Special equipments Manpower and time needed Information to be saved in database

2.2 System Checkout

Checkout of High Voltage system Description Connect the detector to HV supply, verify cable map,

switch on, check of current monitor.

Manpower and time needed

Software  CLAS12 slow control
Computing resources  NA

Dependencies from other systems Cooling system must be checked out prior to HV system.

Information to be saved in database HV distribution map

Checkout of Low Voltage system Description Connect the detector to LV supply, verify cable map,

switch on, check of current and voltage monitor.

Manpower and time needed

Software  CLAS12 slow control
Computing resources  NA

Dependencies from other systems Cooling system must be checked out prior to HV system.

Information to be saved in database LV distribution map

Checkout of the Gas systems Description 1. Nitrogen lines: gas flow, humidity, leak tests.

2. Cooling air lines: gas flow, temperature, humidity,

leak tests.

Manpower and time needed  two weeks
Software  CLAS12 slow control
Computing resources  NA

Dependencies from other systems HV and LV must be checked out prior to gas systems.

Information to be saved in database Flow, pressure, humidity and temperature data

Checkout of the Safety System Description Checkout and test of the interlocks between HV, LV, cool-

ing, gas systems

Manpower and time needed  one week
Software  CLAS12 slow control and safety system
Computing resources  None
Dependencies from other systems  All interlocked systems

Information to be saved in database Minimum pressures, temperatures and flows for the interlocks

Checkout of the Front-End electronics Description ASIC and FPGA configuration, calibration, channel

mapping, noise level, etc

Manpower and time needed

Software  CLAS12 DAQ and slow control, calibration software

Computing resources Dependencies from other systems Cooling system, HV and LV must be checked out prior

to HV system.

Information to be saved in database Channel map, calibration data

Checkout of the DAQ and trigger Description Test of different DAQ and trigger configurations

Manpower and time needed  1 week
Software  CLAS12 slow control and DAQ
Computing resources  Computer farm
Dependencies from other systems  Need DC information
Information to be saved in database RICH electronics configuration data

Cosmic runs with the electronic panel (EEL124) Description Check of the full electronic system.

Data will be acquired with the electronic panel put in horizontal position, with the MAPMT entrance window up. A simple tracking system could be setup for determining the cosmic trajectories.

DAQ configuration and trigger  RICH DAQ software, dedicated trigger
Manpower and time needed  two weeks
Software for analysis of results  RICH analsys software
Computing resources  Access to batch computing farm
Dependencies from other systems  Cooling system and interlocks must be on.
Information to be saved in database NA

Cosmic runs with the whole RICH (EEL-124) Description Check of the RICH with cosmics.

Data will be acquired with the RICH put in horizontal position on its transportation trolley, with the aerogel panel down. Cherenkov photons will be produced in the aerogel, then reflected back by the frontal mirror toward the photodetectors. A simple tracking system could be setup for determining the cosmic trajectories.

DAQ configuration and trigger  RICH DAQ software, dedicated trigger
Manpower and time needed  two weeks
Software for analysis of results  RICH analisys software
Computing resources  Access to batch computing farm
Dependencies from other systems  Cooling system and interlocks must be on.
Information to be saved in database NA

3 Commissioning Without Beam

3.1 Special Calibration Procedures

Pedestal runs Description Determine the baseline of the Front-End electronics

DAQ configuration and trigger  Clock trigger

Manpower and time needed Software for analysis of results Computing resources

Dependencies from other systems  HV on/off to compare noise levels
Information to be saved in database Pedestals

Dark runs Description Calibration of the Front-End electronics using thermal

noise.

DAQ configuration and trigger  Internal trigger

Manpower and time needed Software for analysis of results Computing resources Dependencies from other systems

Information to be saved in database Single p.e. level and resolution

Charge injector runs Description Calibration of the Front-End electronics using the inter-

nal charge injector

DAQ configuration and trigger  Internal trigger

Manpower and time needed Software for analysis of results Computing resources Dependencies from other systems

Information to be saved in database Single p.e. level and resolution

3.2 Calibration with Cosmic Rays

Cosmic runs in Hall B Description Check of the RICH with cosmics.

DAQ configuration and trigger  CLAS12 DAQ and trigger for cosmics
Manpower and time needed  two weeks
Software for analysis of results  CLAS12 analysis software
Computing resources  Access to batch computing farm
Dependencies from other systems  RICH fully operating, CLAS12 tracking system
Information to be saved in database NA

3.3 Commissioning With Beam

RICH detector reconstruction calibration Description After initial system checkout, a series of runs with differ-

ent conditions will be performed.

1. Runs at different beam current to study the noise level.

2. Runs with torus off to check the detector geometry.

3. Runs with different torus magnetic field, including reverse field, to study the performance of the detector.

DAQ configuration and trigger  CLAS12 electron trigger
Manpower and time needed  one day of CLAS12 data taking
Software for analysis of results  CLAS12 tracking and RICH reconstruction software
Computing resources  Access to batch computing farm
Dependencies from other systems  All the CLAS12 detector on

Information to be saved in database Several tuning parameters for the RICH reconstruction (background level, tracking resolution, single photon resolution, etc.).

RICH detector PID in the direct light case

Description Study the Kaon/Pion and Kaon/Proton rejection powers in the case of direct detection of the Cherenkov photons. Production data taken with liquid hydrogen target. Narrow resonances will be used to verify the RICH PID, for example:

1. K_{S} for pions.

2. ϕ for kaons.

3. Λ for protons.

DAQ configuration and trigger  CLAS12 electron trigger
Manpower and time needed  few hours of CLAS12 data taking
Software for analysis of results  CLAS12 and RICH reconstruction and PID software
Computing resources  Access to batch computing farm
Dependencies from other systems  All the CLAS12 detector calibrated

Information to be saved in database Kaon detection efficiency vs pion and proton contamination.

4 Contact Persons

RICH contac persons

Name  Affiliation  email  Area of responsibility
V. Kubarovsky  JLab  vpk@jlab.org  Hardware/Software
M. Contalbrigo INFN-Fe mcontalb@fe.infn.it Hardware/Software
M. Mirazita INFN-LNF mirazita@lnf.infn.it Hardware/Software