AIDA-2020 Advanced European Infrastructures for Detectors at Accelerators. Milestone Report

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1 AIDA-2020-MS15 AIDA-2020 Advanced European Infrastructures for Detectors at Accelerators Milestone Report Design specifications of test stations for irradiated silicon sensors and LHC oriented front-end electronics Curras, E. (CERN) et al 24 June 2016 The AIDA-2020 Advanced European Infrastructures for Detectors at Accelerators project has received funding from the European Union s Horizon 2020 Research and Innovation programme under Grant Agreement no This work is part of AIDA-2020 Work Package 14: Infrastructure for advanced calorimeters. The electronic version of this AIDA-2020 Publication is available via the AIDA-2020 web site < or on the CERN Document Server at the following URL: < Copyright c CERN for the benefit of the AIDA-2020 Consortium

2 Grant Agreement No: AIDA-2020 Advanced European Infrastructures for Detectors at Accelerators Horizon 2020 Research Infrastructures project AIDA MILESTONE REPORT DESIGN SPECIFICATIONS OF TEST STATIONS FOR IRRADIATED SILICON SENSORS AND LHC ORIENTED FRONT- END ELECTRONICS MILESTONE: MS15 Document identifier: AIDA-2020-MS15 Due date of milestone: End of Month 12 (April 2016) Report release date: 24/06/2016 Work package: Lead beneficiary: Document status: WP14: Infrastructure for advanced calorimeters CERN Final Abstract: The energy resolution in sampling calorimeters with silicon sensor read out is strongly affected by energy-loss fluctuations (Landau fluctuations) in the energy deposits of charged particles in the thin sensor layer. Studying these effect requires the development of a specific test station that is described in this document. This test station allows the study of the landau distribution of highly irradiated silicon sensors operating at temperatures of -35 C and below with low humidity (RH < 5 %) and using a very low noise amplifier for the readout of the sensors. A successful program of first measurements carried out on the newly constructed setup demonstrates the ability of the test set up to meet the requirements for the silicon sensor development associated with future High Granularity Calorimeters. AIDA-2020 Consortium, 2016 Grant Agreement PUBLIC 1 / 7

3 AIDA-2020 Consortium, 2016 For more information on AIDA-2020, its partners and contributors please see The Advanced European Infrastructures for Detectors at Accelerators (AIDA-2020) project has received funding from the European Union s Horizon 2020 Research and Innovation programme under Grant Agreement no AIDA-2020 began in May 2015 and will run for 4 years Authored by Delivery Slip Name Partner Date E. Curras M. Moll CERN 29/04/2016 Edited by M. Mannelli CERN 06/06/2016 Reviewed by V. Boudry R. Pöschl [WP coordinator] F. Simon [WP coordinator] F. Sefkow [Scientific coordinator] CNRS-LLR CNRS-LAL MPG-MPP DESY 24/06/2016 Approved by Scientific Coordinator 24/06/2016 Grant Agreement PUBLIC 2 / 7

4 TABLE OF CONTENTS 1. Introduction Test stations Description Test Station's elements Measurements and results Conclusion References... 7 Annex: Glossary... 7 Grant Agreement PUBLIC 3 / 7

5 Executive summary This activity concerns the development of a test station for the characterization of irradiated silicon sensors and LHC-oriented front-end read-out electronics. The development of the front-end electronics test-stations is less well advanced, as the chips in question are still under development, and a good understanding of the features of the electronics is necessary in order to properly specify the corresponding requirements for the stations. With this in mind, and given that the requirements for the silicon test stations are better understood, the priority so far has been put on the development of the silicon sensor test facility. Energy-loss fluctuations (Landau fluctuations) in the energy deposits of charged particles in the thin sensor layers and the high radiation levels characteristic for hadron colliders will affect the energy resolution at low energy and the efficiency in sampling calorimeters. Studying these effects, and in particular the impact of radiation damage, requires the development of a dedicated test station. A test station was designed and built according to these requirements and is presented in this report. The setup can be operated at temperatures of -35ºC and below with low humidity (RH < 5 %) and is using a very low noise amplifier for the readout of the sensors. An extensive measurement campaign on irradiated silicon diodes of different physical thickness for the CMS HGC (High Granularity Calorimeter) has been performed using this test station. The campaign served to commission the setup and to obtain valuable data for understanding the sensor performance in harsh radiation environments. The measurements were already presented in an international conference in February and will soon be published in the conference proceedings. It is foreseen to extend the functionality of the test set up such that it can also be used for the characterization of irradiated SiPMs, which is of high importance for scintillator-based High Granularity Calorimeters. 1. INTRODUCTION The energy resolution at low energy, and the efficiency in sampling calorimeters with silicon sensor readout is strongly affected by the Landau fluctuations in the energy deposits of charged particles in the thin sensor layer. The high radiation levels characteristic of hadron colliders will reduce the charge collection efficiency and increase the noise; both affect the characteristics of the observed pulse height distribution. Studying this effect requires test stations capable of operating at or below -35ºC, to reduce the noise due to radiation-induced leakage current, and instrumented with a fast (~20ns) and low noise (~1000e-) amplifier and read-out chain. Grant Agreement PUBLIC 4 / 7

2. TEST STATIONS 2.1. DESCRIPTION Following the requirements described in the introduction, a test station has been built, which is now fully operational.

6 2. TEST STATIONS 2.1. DESCRIPTION Following the requirements described in the introduction, a test station has been built, which is now fully operational. This test station allows the study of the Landau fluctuations of energy deposition and charge collection efficiency by observing the width of the resulting pulse height distribution of highly irradiated silicon sensors operating at temperatures of -35 C (and lower temperatures if necessary) with low humidity (RH < 5 %). A Sr-90 source is used to produce the signal in the sensors which is picked up by a very low noise amplifier (( /pF) electrons). Figure 1 shows all the relevant elements of the test station. The elements are numbered in the picture and will be described in detail in the next section. Fig. 1 Elements of the test station. Left: Outside view with the electronics rack to the left and the climate chamber holding the sensor under test in the inside. Right top: Radioactive Source, amplifier and sample holder inside the climate chamber. Right bottom: GUI of the LabVIEW software controlling the system components and performing the data acquisition. Grant Agreement PUBLIC 5 / 7

7 2.2. TEST STATION'S ELEMENTS Binder climatic chamber MKT115 (1): can be set to temperatures between -70 C and +180 C, keeping inside a low humidity atmosphere (below 5% RH) Agilent 2.5GHz oscilloscope (2): for the triggering and data acquisition. Low voltage power supply (3): up to 25V for biasing the amplifiers (7) and photomultiplier (12) Digital multimeter (4): reads a pt1000 resistance placed close to the sensor that is used for obtaining the correct value of the temperature in the sensor. Despite the temperature inside the climatic chamber being very stable and quickly settled, the cooling of the sensor towards ambient temperature needs more time such that the extra reference provided by the sensor is required. High voltage power supply (5) for biasing of the sensor while measuring the leakage current at the same time. It can go up to 1000V. PC and GUI (6): A PC controls the different devices of the set up through a LabVIEW GUI customized for this test station. CIVIDEC amplifier (7): is used for the readout of the sensors. It is a very low noise charge amplifier that has been optimized in collaboration with the company CIVIDEC for measuring highly irradiated sensors. Strontium-90 radioactive source (8): The beta source is used for the measurements and characterization of the energy loss distribution in the irradiated silicon sensors. Collimator (9): Different size collimators are used for controlling the trigger rate and the beam spot under the strontium-90 radioactive source. Support for the silicon sensor (10): The sensor has to be aligned with the radioactive source and the photomultiplier. NewPort XY stages (11): Special stages for the positioning of the sensor are used. They can be operated at very low temperatures inside the climatic chamber with a precision of a few microns. Scintillator and Photomultiplier (12): These are needed for the triggering. 3. MEASUREMENTS AND RESULTS A complete campaign of measurements of silicon diodes for the HGCAL has been carried out to commission and optimize the test station. Silicon diodes of 5 5 mm 2 and thicknesses between 50 μm and 300 μm have been measured. The diodes have been irradiated to neutron fluences up to n/cm 2. Fig. 2 shows the energy loss distribution for 300 μm thick diodes. It is seen clearly how the charge distribution is changing (degrading) with increasing radiation damage (neutron fluence). Grant Agreement PUBLIC 6 / 7

8 Fig.2: Distribution of the pulse height (in mv), proportional to the collected charge obtained with a Strontium- 90 beta source on 300 μm thick sensors operated at a temperature of -20 C and a depletion voltage of 600V. Some important results from the measurement campaign have been presented in the 14 th Vienna Conference on Instrumentation in February 2016 and will soon be published in the conference proceedings [1]. 4. CONCLUSION A laboratory test stand for the characterization of the charge collection efficiency and energy loss fluctuations of highly irradiated silicon sensors has been designed and built according to the specifications corresponding to the requirements for the sensor use in future high granularity hadron calorimeters. A very successful program of measurements carried out on the test stand has served for the commissioning. The fact that first data obtained on the setup are now under publication in a scientific journal, clearly demonstrates that the setup is fully operational. It is foreseen to extend the functionality for the characterization of irradiated SiPMs which are of importance for scintillator based High Granularity Calorimeters. 5. REFERENCES [1] E. Curras, et al., (2016) Radiation hardness and precision timing study of silicon detectors for the CMS High Granularity Calorimeter (HGC). 14 th Vienna Conference on Instrumentation proceeding, Feb 15-19, Vienna (Austria). Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment; accepted for publication. ANNEX: GLOSSARY Acronym HGC CMS Definition High Granularity Calorimeter Compact Muon Solenoid Grant Agreement PUBLIC 7 / 7

Radiation hardness and precision timing study of Silicon Detectors for the CMS High Granularity Calorimeter (HGC)

Radiation hardness and precision timing study of Silicon Detectors for the CMS High Granularity Calorimeter (HGC) Esteban Currás1,2, Marcos Fernández2, Christian Gallrapp1, Marcello Mannelli1, Michael