cern-lhcc-2010-013 atlas tdr 19 a t l a sdarbo/ibl/stuff/ibl_tdr_addendum_v1.3.pdf ·...

A T L A S Insertable B-Layer Technical Design Report

TDR

CERN-LHCC-2010-013

ATLAS TDR 19 4 May 2012

Addendum

IBL TDR Addendum

ATLAS Project Document No: Institute Document No. Created: 17/03/2012 Page: 1 of xx

ATL-SYS-XX-XXX

Modified: Rev. No.: 1

IBL TDR Addendum Abstract

This document is an addendum of the ATLAS IBL TDR of September 2010. This document focuses on the “Mixed Scenario” where staves are populated in the centre with two-chip planar sensor modules and with single-chip 3D sensors at the two extremities. We also describe the diamond beam monitor that uses the diamond sensors originally developed for the IBL.

Prepared by: IBL Management Board + D. Ferrere, C. Gemme, W. Trischuk.

Checked by:

Approved by: G. Darbo, H. Pernegger, M. Nessi, B. Di Girolamo

Distribution List ATLAS IBL Collaboration for comments

ATLAS Project Document No: Page: 2 of 13

ATL-IP-XX-XXX Rev. No.: 1

History of Changes

Rev. No. Date Pages Description of changes

1 1.1 1.2 1.3

17/03/2012 30/04/2012 4/05/2012 7/05/2012

All All, Sec.2.4 Sec. 2.3, 3 All

First Draft Overall editing. Added section 2.4. Added section 2.3 and 3. Improvement from W. Trischuk.



Table of Contents

1 INTRODUCTION ................................................................................................................ 4

1.1 Sensor Qualification and Production Status ............................................................................................................... 4

2 MIXED SENSOR SCENARIO ............................................................................................ 6

2.1 Module Layout ............................................................................................................................................................... 6

2.2 Stave Layout ................................................................................................................................................................... 7

2.3 Module Loading on Stave .............................................................................................................................................. 8

2.4 Electrical services ......................................................................................................................................................... 10

3 DIAMOND BEAM MONITOR (DBM) ............................................................................... 11

4 REFERENCES ................................................................................................................. 13



1 INTRODUCTION At the time the IBL TDR [1] was submitted in September 2010, the sensor technology was not decided. Three technologies were considered for the IBL: planar sensors (n-on-n and n-on-p), 3D sensors (with active or slim edge) and diamond sensors. A program of extensive testing of detector assemblies irradiated to IBL fluence of 5x1015 neq/cm2 and 250 Mrad was carried out through the Spring of 2011. Results were presented to a sensor technology review in July 2011. The review panel recommendation was to investigate a “mixed scenario”, in which the 3D technology populates the highest eta region of the IBL where the tracking could take advantage of the electrode orientation to give a better z-resolution after heavy irradiation. The implications of the IBL “mixed scenario” are presented in section 2 of this Addendum document with emphasis on how this affects the module, stave and services design. The Diamond Beam Monitor (DBM) [5] is presented in section 3, which is a spin-off from the IBL technology with prototype assemblies of FE-I4 and diamond sensors. The DBM is a detector that is constructed by the IBL collaboration and will only be installed, if the existing ATLAS Pixel detector is brought to the surface in 2013 to replace the Service Quarter Panels (nSQP project Error! Reference source not found.).

1.1 Sensor Qualification and Production Status Between the end of 2010 and early 2011, the plans for construction of the IBL were substantially modified by two events: the change in the LHC long shutdown planning (necessary to install the IBL) and the very good results of the FE-I4A front-end chip. The latter raised confidence that only minor changes would be needed for the production version of this chip. The LHC shutdown to install the IBL, assumed in the IBL TDR, was for the end of 2015. The decision of LHC (Chamonix 2011) to have a long shutdown in 2013/14 offered ATLAS the serious possibility to install the IBL two years earlier. From all the sensor technologies under study for IBL the two that were more advanced and at asufficiently mature stage for possible production were: planar n-in-n and double sided 3D sensors. It was therefore decided to restrict the qualification to these two technologies and develop FE-I4 modules from these two to be fully qualified in test beam studies and at full IBL radiation dose. To fulfil this “sped up schedule” it was decided, in January 2011, to launch a pre-production of planar sensors from CiSi and of double sided 3D sensors from CNMii and FBKiii. A further idea behind these production runs was to already have between 30% and 50% of the sensors available by the time of the qualification deadline and sensor review. The path chosen to streamline the sensor prototyping and decision, the success of version A of the FE-I4 with minor needs for modification together with the high production yield, also streamlined the production of the FE-I4B by making engineering and production in an single run. Together these saved over one year in the IBL schedule. Further optimization and reduction of the originally generous contingency in the schedule gained the needed time to be ready for the phase 0 LHC shutdown in 2013/14. Figure 1 compares the IBL TDR schedule with the present schedule for the major detector items. The FE-I4B and sensor production were almost completed as of March 31st 2013, meeting the new schedule for these critical items.

Figure 1: Comparison between the IBL TDR schedule (version v.3) and the version prepared for the IBL installation in the 2013/14 LHC shutdown. The comparison is made for the major production items going into the detector.

i CiS: Forschungsinstitut fur Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Strasse 14, 99099 Erfurt, Germany ii CNM: Centro Nacional de Microelectronica (CNM-IMB-CSIC), Campus Universidad Autonoma de Barcelona, 08193 Bellaterra (Barcelona), Spain. See http://www.imbcnm.csic.es. iii FBK: Fondazione Bruno Kessler (FBK), Via Sommarive 18, 38123 Povo di Trento, Italy. See http://www.fbk.eu.

28.09.201116.09.2011

28.11.2011 26.10.2012 333 16.09.2011 09.12.2011 84 26.08.2011 24.02.2012 182 28.02.2011 03.02.2012 340 19.08.2011 17.08.2011 2- 01.01.2011 03.02.2012 398 09.04.2012 25.06.2013 442 27.09.2011 17.10.2012 386 27.08.2012 16.09.2013 385 27.04.2012 18.01.2013 266 21.11.2011 24.08.2012 277 09.01.2012 22.11.2012 318 30.07.2013 21.03.2014 234 12.07.2012 20.03.2013 251

Schedule v3 (ready for installation in 2015) Ready for installation (18.05.2015)

Schedue v5.3a (ready for installation in 2013) Ready for installation (01.07.2013)

Bare stave production & QA

Module loading, testing and QA

FE-I4B Design

FE-I4B Production

Slim edge planar sensor production

Slim edge 3D sensor production

Bump-bonding production

Module assembly

3 4 1 2 3 41 2 3 4 1 2

2013 2014 20151 2 3 4 1 2 3Task Name Start End Days

2011 20124



The recommendation from the sensor review panel, in July 2011, were that both sensor technologies fulfilled the IBL requirements, and that there was an opportunity to populate the forward region with 3D where the tracking could take advantage of the electrode orientation to give a better z-resolution after heavy irradiation. The IBL collaboration, following that recommendation from the review panel, decided to complete the production of planar and 3D sensors and endorsed the proposal to build enough modules for a mixed IBL sensor scenario where 25% of 3D modules populate the forward and backward part of each stave. The production of planar sensors will also allow coverage of 100% of IBL in case that is needed. The fractions of planar and 3D sensors that can be put in the IBL are quantized by the granularity of the high voltage services, which individually bias a group of four FE-I4 equivalent area of sensors (i.e. 4 FE-I4 out of 32 in a stave). Preserving backward/forward symmetry of the IBL restricts to multiples of 25% the fraction of planar/3D that can populate each stave. Table 1 and Table 2 show a summary of the planar and 3D sensor production as of the 31st of March 2012. There are enough sensors from both technologies to fulfil the mixed scenario, considering the expected overall yield for the module production and stave loading.

Batch # 1 2 3 4 5 6 Total

Received wafers 20 22 18 20 17 22 119

Good DC sensors 69 76 64 70 62 83 424

Yield 86.3 % 86.4 % 89.9 % 87.5 % 91.2 % 94.3 % 89.1%

Table 1: Status of two-chip planar sensor production at the end of March 2012. The IBL in the 75% of planar scenario has 168 sensors.

Status Produced Wafers

Selected Wafers

Yield on selected

Good sensors

FBK-A10 Completed 20 12 60 % 58



FBK-A13 In proc. (backup batch) - -

CNM-1 Completed 19 18 60 % 86

CNM-2 Completed 17 15 71 % 85

CNM-3 In proc. - - - -

Total 62 62 % 306

Table 2: Status of planar single-chip 3D sensor production at the end of March 2012. The IBL, in the 25% of 3D scenario, has 112 sensors.

In addition to the sensor qualification and production, thin modules have been developed with both sensor technologies, making single and double-chip assemblies. The prototyping was carried out with 100 µm and 150 µm thin FE-I4A chips. For the aggressive IBL installation plan, it was decided to use the 150 µm thickness to be on the safe side to avoid unexpected yields issues.

Table 3 summarizes the production of thin modules. Several such modules have been dressed with the flex hybrids and are ready to be installed on “stave 0”.



FE-I4 Thickness

Planar (200µm) Single Chip Double Chip

3D (230µm) Single Chip

Total FE-I4

100 µm 4 22 7 55

150 µm 16 17 20 70

Total 20 39 27 125

Table 3. Modules bump-bonded at IZMiv with thin FE-I4A chips to qualify the stave assembly procedure.

2 Mixed Sensor Scenario This section describes the main changes from the IBL TDR design to execute the mixed sensor scenario. The impact of the mixed sensor scenario on the IBL construction is on the following items:

• Module design. • Stave layout. • Module loading on stave. • Electrical services.

2.1 Module Design. The IBL module outlines for two-chip modules and one-chip modules are geometrically compatible; the physical size of two single-chip 3D sensor assemblies is the same width as a single planar two-chip module. The differences in rφ between the two sensor technologies are compatible with the overall IBL envelopes. In Table 4 are listed the geometric parameters for the sensors used in the IBL mixed scenario. Bare module assemblies are dressed by gluing a flex hybrid circuit on the sensor side; there are two circuits, one for single-chip 3D assembly and another for the planar double-chip assembly. Such circuits are shown in Figure 2. They are mechanically different, but electrically very similar once the test pigtail is cut. Having two flex-circuits eases the assembly procedure, but does not change the electrical connections, which will basically remain separate for each of the two FE-I4 chips in the double-chip version. In the case of the double-chip module flex, there are two separate wire-bonding fields that bring the signals from the stave flex “wings” together. The connection step, once the modules are on the stave, is the same for two single and one double module. In this way the stave flex connections are compatible for either single or double chip modules.

Table 4: Main geometrical parameters of the IBL sensor used for planar and 3D sensor modules.

A few special precautions have been used in the design of the module flex:

• The back of the flex (which is glued on the module) uses a 25µm thick polyimide film based coverlayv which is rated to stand 100V/µm to hold the 1000V needed by the planar modules once they have received their full integrated radiation dose. It was sensible to do the same for the 3D modules, even if it is planned to have between 160 and 180 V as the maximum operation voltage. The extra radiation length is very small.

iv Fraunhofer IZM-Berlin, Gustav-Meyer-Allee 25, 13355 Berlin v SF302C polyimide film from Shengyi (http://www.syst.com.cn/en/index.html)

Structure Planar 3D

Gap b/w modules 205 µm 205 µm

Sensor thickness 200 µm 230 µm

Module width (along z) 41 315 µm 20 450 µm

Bias tab / guard-ring extension (in rφ) 630 µm 1 230 µm



• The high voltage capacitors are encapsulated using an isolating resin. The prime candidate is a Polyurethane resin

(PUR)vi that was used for the ATLAS SCT.

Figure 2: Module Flex Hybrid for single chip (left) and double chip module (right). The flexes come with a pigtail and a test connector, which is cut away before loading on stave. The stave flex wing is glued on the module flex and then connections are provided by wire bonding. The double chip flex is electrically equivalent to two single chip ones.

The clock and data signals, which are individual lines on the stave flex, are routed separately on the double module flex to the input of each FE-I4. Each line is terminated with a 160Ω resistance. This is acceptable as the two stubs only 4 cm long and the frequency of the signals are 40/20 MHz for the clock/data. Single-chip modules use the same routing topology on two separated flexes.

• The two FE-I4 chips on a single module are differentiated by having their ID addresses connected to a pull-up wire-bond connected to VDD.. For the double-chip module, the additional wire-bond is used for only one of the two chips. When the single-chip modules are mounted on a stave, the wire-bond of one of the two chips making a logical module will have the ID address wire-bond removed.

• The module flexes are produced with a surrounding frame having precision holes for positioning pins in the mounting jigs. When the pigtail is cut, the frames are removed and the modules can then picked up by vacuum tools. This is done at the last moment, before loading to the stave.

All tooling and jigs for assembling the modules are made such as to be compatible with both designs. The module testing is done using the USBPix readout system. Two USBPix systems are connected in master/slave configuration to a double-module using the test connector and an adapter card. Both single and double-chip modules use the same adapter cards; double modules use an additional pin for the extra signal on the test connector.

2.2 Stave Layout The mixed sensor scenario stave layout is shown in Figure 3. The 3D sensors populate the 2 extremities. The area covered with planar and 3D sensors is, respectively, 75 % (equivalent to 24 FE-I4 chips) and 25 % (equivalent to 4+4 FE-I4 chips). The modules have a fixed gap of 205 µm. The planar and 3D modules differ slightly in thickness: from 200 µm to 230 µm; and in rφ where the 3D modules are 700 µm wider. The 3D design is compliant for the double and single sided design (active edge), having the second one the high voltage connection being made on the same side as the bump-bonding. For this compliant reason the sensor extends beyond the FE-I4. Figure 4 shows a cross-section of the stave, (top) at the position of a planar double-chip module and (bottom) at the position of a 3D single-chip module.

vi VU 4453 from Peters (www.peters.de).



Figure 3: Stave layout for the mixed sensor scenario. 3D sensor modules populate the two stave extremities. The gaps betweenneighbouring modules is fixed at 0.205 mm.

Figure 4: Stave cross sections at the position of a planar module (top) and a 3D module (bottom).

2.3 Module Loading on Stave The module loading integrates the stave and stave-flex together with the planar and 3D detector modules while targeting for the highest quality in term of working pixel and modules and the long term reliability. The 16 procedural steps, followed by the module loading and QA sites are:

1. The reception of the completed stave with the stave-flex. This is part of the QA to validate that the stave with the glued stave-flex has a conformal geometry after it has been thermally cycled 10 times from -40°C to +40°C.

2. The reception tests of modules. Detector modules qualified at the assembly sites pass visual inspection and basic electrical readout tests at loading site, before the module-flex test pigtail is cut to load them on the stave.

3. A “Guillotine tool” cuts the module pigtail. The next operation consists in the removing the wire bonds from the pads that will be re-used to connect the stave-flex wings. These same pads were previously used to electrically connect the module test pigtail before loading the module to the stave (see Figure 2).

4. The modules are loaded on the first half of the stave (Figure 5). Six planar and four 3D modules are positioned using precise mechanical references (dowel pins). Module placement accuracy is based on the sensor dicing accuracy, which is +/- 10 microns. The gap between modules of 205 µm (see Figure 3) is fixed by polyimide-coated shims that have a thickness of 190 µm.

5. The modules are loaded on the second half stave with the same positioning technique.



6. The 32 flex-wings that are retracted during loading are then released and glued on the module flex with Araldite

2011 (epoxy glue) (see Figure 5). 7. Once the wings are glued, the electrical interconnection between the module-flex and the stave-flex (wings) is

done by wire-bonding. Multiple wire-bonds are used for redundancy. The connections bring out FE-I4 power and I/O LVDS signals, sensor bias and connections to NTC temperature sensors placed on the module-flexes. Test wire-bonds are then pulled to control the quality of the wire-bonding process.

8. The loaded stave is electrically connected through an adapter card to the readout system and cooled by a CO2 system. This step qualifies the stave in near real operating conditions. Reworking is done in case as needed before shipping to CERN for integration into the IBL.

9. The module positions are surveyed with respect to stave references. 10. The complete stave is thermally cycled. Ten thermal cycles from -40°C to +40°C are foreseen in the QC

procedure. Assembly weaknesses and infant mortality are detected and corrected in this way. 11. The survey is repeated and the results are compared with those from step 9. If displacements or distortions are

seen, rework will be considered. Such positions are recorded and will be used for initial alignment of the detector modules in the IBL.

Figure 5: Tooling to load modules on stave. On the right side are visible four 3D single-chip modules, while another six double-chip planar modules are shown toward the centre of the stave. Modules are positioned with respect to the cut edge of the sensors. In the 200µm gap between modules a PEEK spacer is inserted to electrically isolate neighbouring sensors. Bottom left illustration shows a planar module loaded with ~40g. The bottom right illustration shows the wing to module flex gluing operation with a jig defining the wing shape during the polymerization.



12. A complete functional test with cooling and readout is performed. This test checks integrity and full functionality

of all the modules. Bump integrity can be checked with pixel noise measurements. Pixels that have lower noise with sensor bias and that have no difference with bias on/off have high probability to be disconnected from the sensor.

13. Adherence to the IBL envelope is verified. This is particularly critical with respect the neighboring IBL staves where the minimum distance is as small as 0.8 mm. Stave-flex wings will be the subjects of the highest attention.

14. The last operations on the stave are to add an insulation spacer in the gap between module groups sharing the same sensor bias and a spacer protecting wire-bonds from mechanical damage from touching another stave during integration in IBL.

15. The stave is finally transported to CERN SR1 surface building for extensive QA test: burn-in, source scan and cosmic tests.

Each stave, before loading with modules, is mounted onto a “handling frame” support jig (see Figure 6). The stave stays on the handling frame for all of its life, until it is integrated as a long (7 m) object (stave + internal services) around the beam-pipe in the IBL. This minimizes mechanical stress in handling staves. The handling frame is made of carbon fibre reinforced plastic (CFRP). Its CTE is about zero and very close to that of the stave. In this way thermal excursions during the thermal cycles do not affect the stave with mechanical stress. Module thermal contact to the stave is guaranteed by thermal grease, which has been qualified for IBL radiation requirements. Two drops of araldite are added to mechanically stabilize the module attachment to stave. The loading tools consist of almost 80 mechanical parts that are linked to the cradles for the various operations. A few of them are specific to the module geometry like: the grease mask, the alignment ruler and guides, the loading weight. The basic tooling set is therefore compatible for a scenario with different fractions of 3D and planar sensor modules: 25/75 mixed scenario or, in case is needed, full planar scenario.

Figure 6: CFRP Handling Frame holding a real stave with mechanical fixation at the two end-blocks and at the middle of the stave (mounted as integrated around the beam pipe). One handling frame is dedicated per loaded stave for all loading, QA and integration operations.

2.4 Electrical services Electrical services have been designed maintaining compatibility between planar and 3D sensors. In particular the high voltage maximum rating of all the components is designed for 1000 V, needed to bias the planar sensors when they reach their full radiation dose. The modularity in the sensor bias voltage was decided as best compromise between having every single sensor tile controlled individually and the constraints from service routing. This modularity was defined in the IBL TDR being a sensor area equivalent to four FE-I4 chips. This is maintained in the mixed scenario. The planar and 3D sensors will see



quite different operating voltages before and after irradiation. For this reason they need to be connected to separate HV supplies. This constraint, together with the modularity in the sensor power distribution, requires a minimum modularity of four FE-I4 chips equivalent in area for each sensor flavour. The additional backward-forward symmetry in the stave limits to multiples of 25% (8 out of 32 FE-I4 chip area per stave) the coverage with either of the technologies. The 25% (3D) / 75% (planar) scenario will use two bias lines for the 3D and six lines for the planar sensors in each stave. For the 3D it is planned to use sensors from both CNM and FBK. They are similar in operational voltage, but for optimal control of the operational settings each HV channel will be connected to only one of the 3D sensor flavours. The bias current requirement for the HV power supply is defined by the sensor leakage current after the integrated dose at the operation temperature. From measurements made during the sensor qualification phase it is found that the planar and 3D sensor have similar currents, between 300 and 400 µA for the area of a single FE-I4 chip at -15ºC and after a dose of 5x1015 neq/cm2 [2]. The difference in the range of operating voltages between planar and 3D suggests the selection of different models of HV power supplies. The two models of power supplies from isegvii:

• Mod. EHS F205n_R51: Voutnom = 500 V / Ioutnom = 10 mA per channel • Mod. EHS F210n_R51: Voutnom = 1000 V / Ioutnom = 10 mA per channel

is an optimal solution to fulfil the sensor requirements. The exisiting ATLAS pixel detector uses HV power supply from the same series. This will simplify the control and monitor software in the experiment.

3 Diamond Beam Monitor (DBM) Beam monitoring, luminosity measurement and tracking in ATLAS, in the future, must continue to operate in radiation environments at least an order of magnitude harsher than experienced by the current detectors. It is observed that, as the environment becomes harsher, detectors lacking fine spatial or timing granularity are challenged to separate of signal from background. To remedy this problem, detectors close to the interaction region are becoming ever more highly spatially segmented. We propose to add the Diamond Beam Monitor (DBM) [5] to ATLAS, which is a spatially segmented upgrade to complement the timing granularity of the existing Beam Crossing Monitor (BCM). Chemical Vapour Deposition (CVD) diamond has a number of properties that make it an attractive alternative for high-energy physics detector applications. Its large band-gap (5.5 eV) and large displacement energy (42 eV/atom) make it a material that is inherently radiation tolerant with very low leakage currents and high thermal conductivity. ATLAS already uses this material in its highly time-segmented (sub-ns) BCM that provides stable luminosity measurements and detailed background characterisations in both during stables beams and while the LHC machine is setting up for collisions.

Figure 7: CAD view of the DBM telescopes inside the new Service Quarter Panels (nSQP) Error! Reference source not found.. Left: An isometric view of the four telescopes, with their type-0 cables (orange) and PP0 patch panels (green) mounted on the innermost nSQP cruciform. Right: Details of the DBM cooling channel (blue) and it’s connection to the from SQP cooling channel (red) between the quarter panel (brown) that will be in place when the DBM telescopes are mounted in July 2013.

The DBM capitalises on R&D undertaken for the diamond bid to be the IBL sensor. We produced 20 single-chip FE-I4 modules with diamond sensors in 2011. When the IBL insertion schedule was advanced to 2013 it was not possible to produce the more than 500 diamond sensors in time to meet the IBL schedule. Instead, we propose to install 24, single-chip IBL modules, with diamond sensors in the forward region of ATLAS, at r = 65 mm from the beam line and |z| ~ 1m, at rapidities from 3.0 to 3.4. Figure 7 shows two views of the DBM telescopes (on one side of ATLAS – the full system has similar arrangements on both sides of ATLAS). Each telescope consists of three single-chip sensors, spread over a 10 cm lever arm. Parametric tracking simulations show this arrangement gives impact parameter resolution of better than 1 mm vii iseg GmbH, Bautzner Landstr. 23, D-01454 Radeberg / OT Rossendorf



for tracks from the interaction point (IP) and allowing us to distinguish them from charged particles originating in the up/down-stream collimators. Even for µ = 40 (µ is the mean events number per bunch-crossing) we expect an average of 4 tracks per telescope from the IP. Initial pattern recognition studies show that the DBM modules will have the granularity to un-ambiguously reconstruct 10 or more tracks per telescope arm with low fake-rates. We are implementing a full GEANT model of the DBM in the ALTAS/IBL/Pixel simulation and will continue performance studies for proton collisions, detector albedo/afterglow and representative beam loss and beam-gas background samples, in the coming months. Conversely for µ = 40 we expect to acquire 10,000 tracks per bunch-crossing over a period of one minute, allowing a 1% precision on the bunch-by-bunch luminosity on a time-scale comparable to the basic ATLAS luminosity block. This should not only preserve the precision of the current BCM luminosity measurements, as the LHC rates continue to increase, but also make it more robust as we get to higher doses with correspondingly higher albedo and background rates. Beyond the DBM patch-panel 0 (the green quarter-circle boards in Figure 7) the signals are bundled into cables that are identical to the IBL half-staves. These, in turn, will feed standard IBL type-2 services and IBL RODs. The DBM event fragments will appear as two additional IBL half-stave. The DBM channels will have twelve FE-I4 chips’ worth of data instead of the sixteen in a real IBL half-stave. The DBM modules will be powered with standard IBL low-voltage (LV) and high-voltage (HV) power supply modules controlled through the standard pixel/IBL control and monitoring system. The only DBM-specific piece of the readout we are developing is an LVDS hit-bus chip that will allow us to accumulate telescope track multiplicities independent of the ATLAS data acquisition system, as a monitor of backgrounds and luminosity even when ATLAS is not taking data. We have assembled and tested ten DBM modules and are working with IZM to finalise the metallisation and bump-bonding procedures. We have studied the performance of four modules in test beams at CERN and DESY and are learning how to calibrate the charge gain for the FE-I4 chip and set the single-channel thresholds to optimise the hit efficiencies for our diamond devices. Over the last year, we have been actively working with a second diamond sensor supplier to complement our erstwhile single source of diamond sensor material. We have received four sensors from this new company that show comparable, or better, signal sizes and have placed an order for ten additional DBM sensors from this new vendor. We expect delivery of these ten additional sensors in July 2012. Finally, we have done extensive thermal and mechanical modelling of the support structure design to ensure that the DBM will be thermally neutral in ATLAS. We are beginning the process of manufacturing the mechanical parts to arrive at CERN by the end of 2012. Table 5 provides details of the remaining DBM construction and installation milestones. More details can be found in [5].

DBM Milestones Date

Testbeam results from Module 0 June 1, 2012

Sensors 1-20 at IZM for module production July 1, 2012

Modules 1-15 ready for Q/A September 1, 2012

Sensors 21-40 at IZM for module production November 1, 2012

Support Mechanics ready at CERN December 1, 2012

Modules 16-32 ready for Q/A January 1, 2013

DBM telescopes 1-5 ready for mounting May 1, 2013

DBM telescopes 6-9 ready for mounting June 15, 2013

Mount DBM telescopes in nSQP July 1, 2013

Table 5: Milestones for DBM construction, assembly, testing and installation in ATLAS nSQP.



4 References [1] ATLAS Collaboration, ATLAS Insertable B-Layer Technical Design Report, ATLAS TDR 19, CERN/LHCC

2010-013, 15 September 2010. [2] IBL Collaboration, Prototype ATLAS IBL Modules using the FE-I4A Front-End Readout Chip, to be published

on JINST. [3] R. Klingenberg, D. Muenstermann and T. Wittig, Sensor Specifications and Acceptance Criteria for Planar Pixel

Sensors of the IBL at ATLAS, ATL-IP-QA-0030, https://edms.cern.ch/document/1212891/1 [4] C. Da Via ̀, M. Boscardin, G. Pellegrini, G-F. Dalla Betta, Technical Specifications and Acceptance Criteria for

the 3D Sensors of the ATLAS IBL, ATU-SYS-QC-0004, https://edms.cern.ch/document/1162203/1 [5] H. Kagan, M. Mikuž and W. Trischuk, ATLAS Diamond Beam Monitor (DBM), ATL-IP-ES-0187,

https://edms.cern.ch/document/1211792/1. [6] Share Point Site of the ATLAS Pixel Service Quarter Panel Reproduction, https://espace.cern.ch/atl-pix-sqp-

ero/Pages/Default.aspx

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