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M.Moll , M.Glaser, C.Joram CERN – PH – TA1 – SD (cern.ch/ssd/) F.Ravotti CERN – TS -LEA

RADMON – Working group meeting – 6.April 2004. Radiation Monitoring for the LHC Experiments - Towards a common activity ? -. M.Moll , M.Glaser, C.Joram CERN – PH – TA1 – SD (http://cern.ch/ssd/) F.Ravotti CERN – TS -LEA. Outline. Our Aim (PH-TA1-SD) Why do we want to start this activity?

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M.Moll , M.Glaser, C.Joram CERN – PH – TA1 – SD (cern.ch/ssd/) F.Ravotti CERN – TS -LEA

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  1. RADMON – Working group meeting – 6.April 2004 Radiation Monitoring for the LHC Experiments- Towards a common activity ? - M.Moll, M.Glaser, C.JoramCERN – PH – TA1 – SD(http://cern.ch/ssd/)F.Ravotti CERN – TS -LEA

  2. Outline • Our Aim (PH-TA1-SD) • Why do we want to start this activity? • What exactly do we want to do? • Radiation Monitoring Technologies • passive devices • active devices • Dosimeter Integration – How to do? • Radiation Monitoring for the LHC Experiments • … Some questions to be answered by the LHC Experiments • Proposal: Rough outline of a work plan • Proposal: Organization of the working group • Proposal: Manpower and Financing of the working group (… to be discussed in the closed session) Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -2-

  3. Our Aim (PH-TA1-SD) Why do we want to start this activity? • Alice, ATLAS, CMS and LHCb expressed their strong interest in monitoring the radiation levels within their detectors. • We (PH-TA1-SD) are running the irradiation facilities in the PS East Hall: • Experience in radiation monitoring for radiation experiments (mainly passive dosimeters) • Experience in irradiation experiments and radiation damage in all kind of equipment/devices, Strong involvement in RD50 Collaboration • Since 2003 Federico Ravotti (TS/LEA) is attached to our group and we are also working on active dosimeters • Federico working on online monitors for CMS / we on monitors for our irradiation facility • From our point of view:(1) Highly interesting work that we want to continue(2) Our developments have reached a quality and status which is extending by far our first interest as monitor for our radiation facility Motivation+ Experience + Interest Start this project to be able to : • Continue and extend our dosimeter developments to serve all LHC experiments • Keep Federico and his experience in our group Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -3-

  4. Our Aim (PH-TA1-SD) What do we want to do? • Develop and characterize dosimeter boards with on-line readout for and together with the LHC experiments • Boards being as flexible as possible (dose/fluence range, sensitivity, particle type, shape of board …) in order to allow and optimal adoption to specific sub-detector environments. • Output signal compatible to all Detector Control Systems • Provide the dosimeter boards and/or active dosimeters to the experiments • Support the experiments in qualifying passive dosimeters What do we not want to do? • Impose our radiation monitoring concepts on the experiments • Integrate the dosimeters / dosimeter boards into the experiments Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -4-

  5. Radiation Monitoring Technologies- Some passive devices - • Polymer-Alanine dosimeters (PADs) • Irradiation breaks up bonds and forms free radicals • EPR can quantify the number of free spins • Radiophotoluminescent glass dosimeters (RPLs) • Ionization charges color centers • UV light excitation releases visible light • Thermoluminescence dosimeters (TLDs) • Emission of light when the material is heated after irradiation • Can be reused after reading (heating) • 7LiF for ionizing radiation • 6LiF for ionizing radiation and neutrons (n,a) capture • Hydrogen Pressure Dosimeters (HPDs) • Polyethylene in a sealed quartz container • Disintegration of the polyethylene by irradiation releases hydrogen • Hydrogen gas pressure is proportional to the received dose • LiF Crystals • Formation of color centers increases light absorption • Activation foils • Nuclear reaction form radioactive isotopes • …. many more, including many active dosimeters: • RADFETs, PIN diodes, OSLs …. Figure: I.Floret (TIS/RP) Note: CERN has a High-Level Dosimetry group in SC(TIS)/RP (H.Vincke, I.Brunner et al.)! Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -5-

  6. Passive Dosimeters Data: I.Floret (SC/RP – High level dosimetry) Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -6-

  7. Radiation Monitoring Technologies- Active devices - … most of the ‘active devices’ can be used as passive dosimeters …. technical details were given in Federicos talk …. just to remind you: Devices and their flexibility • RADFETs • different gate oxide thicknesses (change of sensitivity) • different gate voltages (change of sensitivity) • different producers, different packaging (change of response, fading) • OSLs - Optical Stimulated Luminescence • doping of the substrate • Standard devices (“pure” OSLs) sensitive to ionizing radiation • Boron doping: increased sensitivity to thermal neutrons • Mixing with Polyethylene: increased sensitivity to fast neutrons • Reverse biased Pin diodes • Equivalent principle to the Inner Silicon Tracker detectors • different size and thickness, epitaxial detectors • different doping levels, oxygenated • Forward biased Pin (photo) diodes • commercial devices – little flexibility Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -7-

  8. Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -8- Fluence to Dose (MIP): 2.666x10-10 Gy cm2

  9. (0.4 mm) BPW34F/Pad  Fequivalent[cm-2] {HEP, nF} (1.6 mm) OSLs  D [Gy] {g, HEP} Pad BPW34F n-OSLth  Fth [cm-2] {nth} Front-end Front-end Front-end n-OSLF  FF [cm-2] {nF} DCS Dosimeter Integration • The most complete option could contain all type of active devices: RadFETs  TID [Gy] {g, HEP} We plan to put a very early prototype board into our irradiation facility this year Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -9-

  10. Dosimeter Integration • The most complete option could contain all type of active devices. • Not for all experiments all dosimeters are of interest and the expected radiation levels in the sub-detectors are very different Build a flexible system: Our present vision of the system: • Maybe a few different boards (shape and number of components) • e.g. with or without the OSLs • most complete system could have e.g. 3cm x 8cm x 3 cm • Maybe modular boards that can be connected together • e.g. one board with RADFETs and Diodes and another one with the OSLs • Foresee a device mounting allowing to plug different kind of devices into the same slot • e.g. RADFETs with different gate oxide fit in the same slot • Foresee to be able to replace dosimeters on a board • e.g. replacement of strongly irradiated or damaged dosimeters Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -10-

  11. …. towards LHC Rough estimate of doses/year Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -11-

  12. Towards a workplan (1/2)…. some questions to be discussed • Measurement for which purpose? • (Beam dump?  Beam Condition Monitor Group) • Detector protection (e.g. switching off a sub-detector) ? • Test of radiation shielding? • Long term monitoring? • Analysis of beam accidents? • Instantaneous dose rate measurement needed ? • trigger on too high dose rate/flux needed? if so, in which time scale? • Measure which kind of information? • ionizing dose • displacement damage • thermal neutrons • Dose/Fluence range and sensitivity needed? • Active and/or passive devices ? • readout cycle? / replacement cycle? Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -12-

  13. Towards a workplan (2/2)… some questions to be discussed • Number of monitoring modules? • Environment of module? • Temperature and Temperature stability? • Space constrains? • Maximum size of sensor module? • Distance between sensor and readout electronics (cable length)? • Lifetime of modules? • Will we be able to repair/replace/upgrade them? • Readout: • Radiation hard electronics on-board needed (OSL needed)? • Specific restrictions due to the individual experiments? • Which kind of signals can be accepted by the detector control system of the Experiment? • Deadlines • Decision about size of the module • Decision about number of cables • Decision about signal type • Installation deadline • Service/Maintenance after installation • Which kind of service/maintenance is expected after installation? Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -13-

  14. A possible work plan • 6/2004 Specification of requirements • Each LHC Experiment documents about its specific requirements • Written agreement between Experiments and dosimeter working group specifying: • responsibilities • work plan and milestones. A work plan could then look like: • End of 2004 • First prototype of an integrated board tested • First prototype of basic readout system ready • Integration into experiments clarified (positions, cabling, signal type) • Middle of 2005 • Components for the radiation monitoring boards ‘fixed’ • End of 2005 • Prototypes of integrated boards with full readout electronics tested • Series production ready to start • Beginning 2006 • First boards ready (Is this too late?) • 2006: Series of radiation tests of full dosimeter boards (final calibration) Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -14-

  15. Organization of the working group • PH-TA1-SD (M.Moll, M.Glaser, F.Ravotti) + external collaboratorstogether with the Experiments: • Design, develop and provide dosimeters and dosimeter module(s) • Coordination of the common efforts within the dosimeter group • Design of front-end electronics (if OSL needed) • Design of basic prototype readout card with standardized output signals • LHC Experiments • Clarification of the specific requirements of the Experiment • Integration into the Experiment (space, mounting, cabling, power supply,..) • Experiment specific detector control interface • Provide one responsible for these activities: Alice (Marc Tavlet, CERN) ATLAS (?) CMS (?) LHCb (?) Michael Moll - CERN PH-TA1-SD – RADMON Meeting, April 6, 2004 -15-

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