Alvarez-Pol, H.

Aumann, T.

Avdeichikov, V.

Bendel, M.

Benlliure, J.

Bertini, D.

Bezbakh, A.

Bloch, T.

Borge, M. J. G.

Briz, J. A.

Böhmer, M.

Cabanelas, P.

Carmona Gallardo, M.

Casarejos, E.

Cederkäll, J.

Chulkov, L.

Cortina-Gil, D.

Di Julio, D.

Dierigl, M.

Duran, I.

Fiori, E.

Fomichev, A.

Galaviz, D.

Gascon, M.

Gerl, J.

Gernhäuser, R.

Golovkov, M.

Golubev, P.

Gonzalez, D.

Gorshkov, A.

Heil, M.

Heinz, A.

Heiss, B.

Henning, W.

Ickert, G.

Ignatov, A.

Jakobsson, B.

Johansson, H. T.

Kmiecik, M.

Krupko, S.

Kröll, T.

Krücken, R.

Kurz, F.

Le Bleis, T.

Löher, B.

Maj, A.

Nacher, E.

Nilsson, T.

Perea, A.

Pfeffer, C.

Pietralla, N.

Pietras, B.

Reifarth, R.

Sanchez del Rio, J.

Savran, D.

Schnorrenberger, L.

Sidorchuk, S.

Simon, H.

Tengblad, O.

Teubig, P.

Thies, R.

Vilan, J. A.

von Schmid, M.

Wamers, F.

Winkel, M.

Winkler, S.

Yanez, P.

Zieblinski, M.

GSI Repository

Progress report of the CALIFA/R3B calorimeter∗D. Cortina-Gil †1, H. Alvarez-Pol1, T. Aumann13, V. Avdeichikov4, M. Bendel7, J. Benlliure1, D.Bertini5, A. Bezbakh11, T. Bloch13, M. Böhmer7, M.J.G. Borge2, J.A. Briz2, P. Cabanelas1, E.Casarejos8, M. Carmona Gallardo2, J. Cederkäll4, L. Chulkov12, M. Dierigl7, D. Di Julio4, I.Durán1, E. Fiori10, A. Fomichev11, D. Galaviz9, M. Gascón1, R. Gernhäuser7, J. Gerl5, P. Golubev4,M. Golovkov11, D. González1, A. Gorshkov11, A. Heinz3, M. Heil5, B. Heiss7, W. Henning7, G.Ickert5, A. Ignatov13, B. Jakobsson4, H.T. Johansson3, M. Kmiecik14, Th. Kröll13, R. Krücken ‡ 7, S.Krupko11, F. Kurz7, T. Le Bleis7, B. Löher10, A. Maj14, E. Nacher2, T. Nilsson3, A. Perea2, C. Pfeffer7,N. Pietralla13, B. Pietras1, R. Reifarth6, J. Sanchez del Rio2, D. Savran10, S. Sidorchuk11, H. Simon5,L. Schnorrenberger13, O. Tengblad2, P. Teubig9, R. Thies3, J.A. Vilán8, M. von Schmid13, M. Winkel7,S. Winkler7, F. Wamers13, P. Yañez8, and M. Zieblinski141Universidad de Santiago de Compostela; 2Instituto Estructura de la Materia, CSIC Madrid; 3Chalmers University ofTechnology, Göteborg; 4Lund University; 5Helmholtzzentrum für Schwerionenforschung, Darmstadt; 6GoetheUniversity Frankfurt am Main; 7Technische Universität München; 8Universidad de Vigo; 9Centro de Física Nuclear daUniversidade de Lisboa; 10Extreme Matter Institute and Research Division, GSI; 11Joint Institute for Nuclear Research,Dubna; 12Nuclear Reseach Center, Kurchatov Institute Moscow; 13Technische Universität Darmstadt; 14Institute ofNuclear Physics PAN, Krakow, PolandCALIFA, the CALorimeter for In Flight detection of γrays and light charged pArticles, surrounds the R3B reac-tion target and is one of the key detectors of the R3B exper-iment [1]. The CALIFA design is optimised for the require-ments given by the ambitious physics program proposed forthe R3B facility and combines very stringent calorimetricand spectrometric properties.The Technical Design Report [2] of the Barrel sec-tion, with a polar angular coverage of 43.2-140.3 o,was approved in January 2013 by FAIR, following therecommendation of the Expert Committee Experiments(ECE) 1. The technical solution adopted for this section,needed to reach the required spectrometric properties,defines a very segmented device with 1952 CsI(Tl) crystalsthat are readout by Large Area Avalanche Photodiodes(LAAPDs). The crystals are orientated within a compactgeometry, with an internal radius of 30 cm, to optimise thecalorimetric properties.The Forward EndCap section (polar angular coverage7-43.2o) is in the R&D phase.The main activities of the CALIFA Working group over2013 have concentrated around three lines of work: a)determination of the final technical specifications and thepurchase of "Barrel" detector components, b) developmentof innovative solutions to fulfil the requirements of the"Forward EndCap" and c) realisation of in-beam tests ofdifferent small size prototypes.The performance of single elements of the CALIFABarrel have been carefully evaluated. Light collection∗Work performed in the CALIFA/R3B Working group and supportedby the Helmholtz International Centre for FAIR† Convener of the CALIFA Working group‡ Also affiliated to TRIUMF1decision adopted in the ECE first meeting in November 2012Figure 1: Prototypes detectors surrounding a 50μm Titarget at IFJ PAN, where irradiation with protons 70 -230 MeV was possible with a beam energy spread betterthan 1%.and output signal proportionality over the crystal lengthare central when long scintillator crystals are used forspectroscopic purposes. These properties can be adjustedby surface treatment, in the CALIFA case by surfacelapping. Considering the large number of crystals involvedin CALIFA it is also important to investigate if an optimumstrategy for surface treatment can be found that couldsimplify industrial production. For this reason models ofthe different crystal geometries have been introduced inGEANT4 and testing procedures for the surface lappinghave been simulated for a large number of different casesby tracing optical photons through the crystals. This workcontinues in parallel with laboratory tests on individualcrystals, already at this stage clear trends can be identidiedbetween the size and position of lapped areas and thelinearity of the response.NUSTAR-KR-09 GSI SCIENTIFIC REPORT 2013144 doi:10.15120/GR-2014-1-NUSTAR-KR-09Beam tests were undertaken at the IFJ PAN Kraków cy-clotron. This accelerator, designed for medical treatment,provides mono-energetic proton beams over an energyrange of 70-230 MeV with a beam energy spread betterthan 1%. A range of smaller size prototypes, correspond-ing to different sections of the CALIFA detector, weretested using scattered protons on a 50μm thick Ti target,the setup is shown in Fig. 1.• A scattered proton beam with energies ranging from70 to 230 MeV was used to irradiate a 4x8 array(ProtoDemo) of 180 mm long CsI(Tl) crystals with atruncated pyramidal shape corresponding to a crystalgeometry used in the Barrel section. The dimensionsof the exit face are well matched to the HamamatsuS12102 double LAAPDs. The signals from the APDswere fed into MPRB-16 preamplifiers. The amplifiedsignals are distributed to FEBEX3 boards, whichcontain two 8-channel fast-sampling ADCs and oneFPGA [3]. To fit the output range of the preamplifierexactly to the input range of the FEBEX boards, anew add-on board was developed for the FEBEXmodule (FAB for FEBEX Addon Board). It adjuststhe baseline of the input signals and implements aNyquist filter to avoid aliasing effects due to the 50MHz sampling of the ADCs. The baseline correctionis active and the correction is directly controlledby the FPGA. The first FAB prototypes have beenimplemented and tested during this beam time,validating the principle of the method. In a secondrevision currently under test, the noise figure and dy-namic range of the boards have been further improved.In addition to detector response to protons over thefull energy range, the prototype was used in variousconfigurations to probe inactive matter effects, whichmay be extrapolated from using the R3BRoot dedi-cated simulation framework. The response to protonswas complemented by a gamma calibration reachingup to 6.13 MeV. A direct scaling of the gamma- proton linear fits reveals a surprisingly uniformrelation, where a common factor of 10.24 (close tothe MPRB-16 preamplifier high - low gain factorof 10) applied to the gamma calibration matchedwell to calibrate over the proton energy range. Theimportance of extending the gamma calibrationenergy is evident on examination of the residuals, asseen in Fig. 2.The high linearity of the CsI(Tl)+LAAPD com-bination looks promising to allow simple gammacalibration scaling to be used as a method to calibrateCALIFA at the R3B proton energies.A new algorithm for particle identification, adapted toFigure 2: Mean proton energy residuals for a sample offive 180 mm CsI:Tl crystals after scaling a 137Cs, 60Cogamma calibration with, and without, the inclusion of the6.13 MeV photopeak (244Cm+13C).real-time use in logic electronics, has been developedfrom the observation and concepts reported in [4].The algorithm showed a clear separation between γrays and protons. Several papers published in 2013detail the R&D campaign and report progress inareas such as advancement in event reconstructionalgorithms and characterization of a range of CALIFAprototype detectors at a number of international facil-ities [5, 6, 7]. They are complemented by R3BRootsimulations which allow to extrapolate to the fullcalorimetric performance of CALIFA.• We also tested a new prototype of the Forward End-Cap: CEPA4. This is an array of 4 individual scin-tillator detectors, each of them consisting of 4 cmof LaBr3(Ce) crystals optically coupled to 6 cm ofLaCl3(Ce) in phoswich configuration (see Fig. 3).Figure 3: Left: schematic view of CEPA4 with its crystals,casing and photomultiplier tubes. During the experiment itwas coupled to a DSSSD allowing the study of proton re-sponse at different positions. Right: proton spectrum at 220MeV. The horizontal axis represent, respectively, the totalenergy deposited in the phoswich (LaBr3+LaCl3) and thepartial energy deposited in the first part of it (the LaBr3).At the top there is a 2-dimensional projection of the plot.The peak corresponding to 220 MeV protons is clearly sep-arated from the rest.GSI SCIENTIFIC REPORT 2013 NUSTAR-KR-09doi:10.15120/GR-2014-1-NUSTAR-KR-09 145The response of CEPA4 to high-energy protons wasmeasured with the available proton beams. The max-imum energy was just enough to test the punch-through of protons in a 10 cm phoswich, which hap-pens at 200 MeV. Fig. 3 right shows a 220 MeV pro-ton spectrum. In this plot the XY-plane represents theenergy deposited in the LaBr3(Ce) versus the total en-ergy deposited in the phoswich, and the Z-axis repre-sents the number of events. The method used to disen-tangle the energy deposited in each of the two crystalsis explained in Ref. [8]. In the plot one can clearly seethe peak corresponding to the 220 MeV protons thathave passed through the two crystals leaving part oftheir energy in each of them. This is the first time theinitial energy of the protons have been reconstructedfrom the partial deposition of their energy in two dif-ferent crystals.• The LaBr3-LaCl3 phoswich concept functions wellover the IFJ PAN proton energy range, though simu-lations highlight potential energy resolution concernswhen employed at the R3B operational energies. Ad-ditionally, the encapsulation required due to the ma-terial’s high hygroscopy introduces inactive matter,which does not aid optimisation of calorimetric per-formance. Therefore, alternative solutions are alsoinvestigated. In particular, the concept of a CsI(Tl)-LYSO phoswich was studied as it contains cheapermaterial which is less hygroscopic and may reducethe amount of dead material required. It would notrequire new readout electronics as the time constants(600 ns and 3200 ns for CsI(Tl) and 40 ns for LYSO)allow for a clear signal separation, however the inter-nal radioactivity of LYSO is a subject of concern aswhen scaled to EndCap proportions the backgroundradiation would be non-negligible. The tested proto-type was composed of two crystals of 1 × 1 × 1cm3from each material coupled with optical glue. Theelectronic pulse allowed a good qualitative identifica-tion of the signals from the energy deposited in bothcrystals. A modified version of the algorithm men-tioned above allowed the reconstruction of the energydeposited as shown in Fig. 4. The illustrated exam-ple shows a good energy reconstruction for the testedenergies, validating this concept for a phoswich. Thecounts outside the branches are related to the differentparticle types and arises from surface effects of thesmall prototype crystals.The development of CALIFA is now entering a very in-tense period. The purchase and construction of 20% of theBarrel has started. The full implementation and commis-sioning of the CALIFA Demonstrator is expected in 2014-2015. In parallel, the submission of the Technical DesignReport corresponding to the Forward section is foreseen bythe end of 2014. According to our schedule, the completeCALIFA could be installed and operational in the R3B caveby the end of 2016.Figure 4: Reconstructed energy deposited in CsI(Tl) as afunction of the reconstructed energy deposited in LYSO forprotons at various energies. Protons punching through the1 cm CsI layer show an increasing signal in LYSO whilethe CsI amplitude is dropping. Protons with energies largerthan ∼95 MeV are not stopped any more and appear in thelower branch of the figure.AcknowledgementsWe would like to thank the full crew of the IFJ PANcyclotron for the support provided during the realizationof the experiment. This work has been supported bythe following projects MINECO (FPA2012-39404-C02-01, FPA2012-39404-C02-02, FPA2012-32443), Xuntade Galicia (GRC2013-11), Swedish research coun-cil (VR 2009-3939, VR 2012-4550, VR 2013-4178),GANAS (Eranet), ENSAR (VII PM), HIC for FAIR,BMBF (05P12WOFNF, 05P12WOFNUE, 05P12RDFN8)and DFG (EXC153).References[1] T. Aumann et al., Technical Proposal for the design, con-struction, commissioning and operation of R3B, A universalsetup for kinematical complete measurements of Reactionswith Relativistic Radioactive Beams (2005).[2] T. Aumann et al., Technical report for the Design, Construc-tion and Commissioning of the CALIFA Barrel: The R3BCALorimeter for In Flight detection of γ rays and high en-ergy charged particles (2011)[3] T. Le Bleis et al., Test of Integration of CALIFA into R3B,GSI SCIENTIFIC REPORT 2012[4] M. Bendel et al., Eur. Phys. J. A. 49 (2013) 69[5] R. Wirth et al., Nucl. Instr. and Meth. A 717 (2013) 77[6] B. Pietras et al., Nucl. Instr. and Meth. A 729 (2013) 77[7] M. Gascon et al., Jour. of Inst. 8 (2013) P10004[8] O. Tengblad et al., Nucl. Instr. and Meth. A 704 (2013) 19NUSTAR-KR-09 GSI SCIENTIFIC REPORT 2013146 doi:10.15120/GR-2014-1-NUSTAR-KR-09

Progress report of the CALIFA/$R^3B$ calorimeter

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Progress report of the CALIFA/ $R^3B$ calorimeter

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Progress report of the CALIFA/R3BR^3BR3B calorimeter

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Progress report of the CALIFA/ $R^3B$ calorimeter