CERN ATLAS Pixel Sensors LASER Setup

Under construction!!!

Introduction

dsfdfsdfsfd frfsfesef dggdhfjf v hfh fj The laser setup schematics show the ....

Theory

If a photon energy is greater than the bandgap energy of a metal, the photon is absorbed through the photoelectric effect. With this energy, an electron in valence band passes to the conduction band; hence, an electron-hole pair is created. In the Silicon, the penetrating light intensity decreases exponentially as I=I0×exp(-αz) in which z is depth and α is the photon absorption probability per unit length. On the other hand, penetration depth is a measure showing how deep an EM radiation can penetrate into a material and it is equal to the reciprocal of α.

The figure shows the change of penetration depth with the wavelength of the light. LASERs are collimated, monochromatic lights having spatial coherence. In our project, we have two different LASER source. Their working frequency are 660 nm(red LASER) and 1060 nm(infrared LASER). By seen on the graph, the 660 nm LASER causes a high energy deposition on the surface of the Si sensor, so it produces charges in 5 µm depth; however, the 1060 nm LASER produces uniformly distributed electron-hole pairs along the beam path inside the detector bulk. Thus, while 660 nm LASER is used for surface charge collection, the 1060 nm LASER is used for deep charge generation.

A relativistic charged particle passes a 300 µm thick sensor in 1 ps and it creates charge in a narrow tube of 1 µm radius around its trajectory. If the lateral size of the LASER beam is much smaller than the detector strip pitch, then the detector response to the LASER will be similar to that of a relativistic charge particle. Hence, by moving LASER across the sensor, charge collection of individual pixels, charge sharing of adjacent pixels can be measured easily and the non-working pixels can be found.

Trigger system

XYZ Stage

Newport
CERN order: EDH 4525355

• 2 Platine de translation motorisée à moteur pas-à-pas UTS100PP, Course: 100 mm, Résolution: 0,1 μm (1/100 pas entier), Répétabilité unidirectionnelle: 1,5 μm, Capacité de charge centrée: 200 N, Vitesse max: 20 mm/s, Longueur du câble: 3 m
• 1 Platine de déplacement vertical motorisée à moteur pas-à-pas UZS80PP, Course: 4,5 mm, Résolution: 0,01 μm (sans codeur), Capacité de charge centrée: ± 30 N, Origine: au centre de la course, Vitesse max: 2 mm/s, Longueur du câble: 3 m
• 1 Contrôleur pour 3 axes ESP301-3N, Pour moteurs pas-à-pas ou à courant continu, 3 A maxi par axe, Puissance maxi disponible: 150 W, Commandes manuelles et affichage en face avant, Interfaces RS232 et USB

RS-212 Communication

The Motion Controller can be controlled by either USB or RS-232 Communication. To control motion controller via RS-232 is still in progress. However, two power sources, HP(Agilent) E3631A and ISEQ SHQ-224M can be controlled by RS-232 communication.

The code to control the power sources can be accessed from the authorities. Basically, it first opens the port according to the specified data frame and then, it asks for commands to send to the power sources. For opening the port, it first asks whether there is an echo from the power source while you are sending your command. 224M sends an echo of each character of command whereas E3631A does not send. So, the code makes two read operation in the first case, but just one read operation in the other. Moreover, to open the port, the code asks the baud rate, number of data bits, parity type, flow control type and number of stop bits to be used. These information are given in the next table.

These information are according to the datasheets. However, in reality, 224M works for any parity type,flow control type and number of stop bits. Also, E3631A works for any flow control type and number of stop bits.

After adjusting the settings, the program asks for command type that you will send. If you want to get some information from power sources, it is a 'Read' command. If you just want to change some parameters of the power sources, it is a 'Write' command. After choosing the type of command, the program asks for the commands to be sent until you want to exit.

Laser system

Laser system

PicoQuant GmbH
CERN order: EDH 4409358

• 1 910002 PDL 800-B
  PDL 800-B Diodenlasertreiber für Pikosekunden Pulse - 5 interne Wiederholraten (5 bis 80 MHz) - externer Triggereingang
• 2 75106
  Kompakte Faserkopplung für einen einzelnen LDH-Laserkopf - Singlemode-Faserkoppler - inkl. variable Abschwächereinheit - inkl. Montage-Fussplatte - Faser wird separat angeboten
• 1 910661 LDH-P-C-660
  Laserkopf für Pikosekunden Pulse - 660 ± 10 nm - inkl. Kollimator und Temperaturstabilisierung
• 1 01958
  Singlemode-Faserkabel - Länge 2.0 m, cutoff < 620 nm - MFD = 4.0 \x{03bc}m, NA = 0.12 - Ausgangsstecker FC/PC - Achtung: Faser nicht vom Koppler entfernen, da dadurch Neujustage notwendig wird
• 1 911063 LDH-P-C-1060
  LDH-P-C-1060 Laserkopf für Pikosekunden Pulse - 1060 ± 10 nm - inkl. Kollimator und Temperaturstabilisierung
• 1 02938
  Singlemode-Faserkabel - Länge 2.0 m, cutoff < 780 nm - MFD = 5.6 \x{03bc}m, NA = 0.12 - Ausgangsstecker FC/PC - Achtung: Faser nicht vom Koppler entfernen, da dadurch Neujustage notwendig wird

Laser optics

Schäfter+Kirchhoff GmbH
CERN order: EDH 4711654

• 1 Fiber Collimator (660nm)
  60FC-T-0-M40-10 Fiber Collimator, focusable, housing diam. 25 mm Monochromat f'40 mm / NA 0.21 / AR 630 - 1080 nm Paraxial coupling axis, FC-PC connection TILT adjustment flange
• 1 Microoptics (660nm)
  13M-M60-10-S Micro-focus optics Monochromat f'60 / NA 0.125 / AR 630 - 980 nm Working distance 54 mm
• 1 Fiber Collimator (1060nm)
  60FC-T-0-M60-08 Fiber Collimator, focusable, housing diam. 25 mm Monochromat f'60 mm / NA 0.14 / AR 980 - 1550 nm Paraxial coupling axis, FC-PC connection TILT adjustment
• 1 Microoptics (1060nm)
  13M-M60-08-S Mikrofokusoptik Monochromat f'60 mm / NA 0,125 / AR 980-1550 nm Arbeitsabstand 54 mm

Optomechanics

Thorlabs GmbH
CERN order: EDH 4711715
CERN order: EDH 4716744
CERN order: EDH 4732937

Related Publications

Related Talks

• Lukas Katzenmeier, Sebastian Dehe - Upgrade des ATLAS-Pixeldetektors, Programme für Messungen an Sensorchips - German Internship Programme 2011 - (Slides pdf,Slides pptx,video)
• Yasin Buyukalp - The Automated Control of the ATLAS Pixel Sensor LASER Setup - Summer Student session 2012 - ( Slides)
• Yasin Buyukalp - The Automated Control of the ATLAS Pixel Sensor LASER Setup - Summer Student session 2012 - Starts at 52th slide - (Video)
• Branislav Ristic - Design and commissioning of a LASER setup for testing ATLAS pixel sensors - Summer Student session 2011 - (Slides)
• Julian Bender, Marc Syväri - Kühlung einer Testapparatur für Sensorchips - German Internship Programme 2012 - (Slides pdf,Slides pptx)

Related Papers

• M. Köhler - Double-sided 3D silicon detectors for the high-luminosity LHC

Useful links

Cern Atlas Pixel Sensors RD TWiki
UsbPix Readout System
STcontrol User Guide FE-I3
STcontrol User Guide FE-I4

• lasersetupschematics.pdf: Laser Setup Schematics

• Penetration Depth vs Wavelength for Si:

• LaserTestsofSiliconDetectors.pdf: Laser Tests for Si Detectors Presentation from Charles University Prague

• SiliconDetectorswithInfraredLaser.pdf: Characterization of Si Strip Detectors with the Infrared Laser

• MotionControllerUserManual.pdf: User's Manual of Newport Motion Controller Model ESP301

• PDL800BUserManual.pdf: User's Manual of PICOQUANT Pulsed Diode Laser PDL 800-B

• UTS-SeriesXYStageUserManual.pdf: User's Manual of Newport UTS-Series XY Stage

• UZS-SeriesZStageUserManual.pdf: User's Manual of Newport UZS-Series Z Stage

• E3631A-PowerSource-UserManual.pdf: HP(Agilent) Power Source E3631A User Manual

• ISEGSHQ224M-PowerSource-UserManual.pdf: ISEG High Voltage Power Supply SHQ 224M Operator Manual