| 1. |
- Ahdida, C., et al.
(författare)
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Fast simulation of muons produced at the SHiP experiment using Generative Adversarial Networks
- 2019
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Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a fast approach to simulating muons produced in interactions of the SPS proton beams with the target of the SHiP experiment. The SHIP experiment will be able to search for new long-lived particles produced in a 400 GeV/c SPS proton beam dump and which travel distances between fifty metres and tens of kilometers. The SHiP detector needs to operate under ultra-low background conditions and requires large simulated samples of muon induced background processes. Through the use of Generative Adversarial Networks it is possible to emulate the simulation of the interaction of 400 GeV/c proton beams with the SHiP target, an otherwise computationally intensive process. For the simulation requirements of the SHiP experiment, generative networks are capable of approximating the full simulation of the dense fixed target, offering a speed increase by a factor of O(10(6)). To evaluate the performance of such an approach, comparisons of the distributions of reconstructed muon momenta in SHiP's spectrometer between samples using the full simulation and samples produced through generative models are presented. The methods discussed in this paper can be generalised and applied to modelling any non-discrete multi-dimensional distribution.
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| 2. |
- Ahdida, C., et al.
(författare)
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The magnet of the scattering and neutrino detector for the SHiP experiment at CERN
- 2020
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 15:01
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Tidskriftsartikel (refereegranskat)abstract
- The Search for Hidden Particles (SHiP) experiment proposal at CERN demands a dedicated dipole magnet for its scattering and neutrino detector. This requires a very large volume to be uniformly magnetized at B > 1.2 T, with constraints regarding the inner instrumented volume as well as the external region, where no massive structures are allowed and only an extremely low stray field is admitted. In this paper we report the main technical challenges and the relevant design options providing a comprehensive design for the magnet of the SHiP Scattering and Neutrino Detector.
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| 3. |
- Ahdida, C., et al.
(författare)
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Sensitivity of the SHiP experiment to Heavy Neutral Leptons
- 2019
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Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; :4
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Tidskriftsartikel (refereegranskat)abstract
- Heavy Neutral Leptons (HNLs) are hypothetical particles predicted by many extensions of the Standard Model. These particles can, among other things, explain the origin of neutrino masses, generate the observed matter-antimatter asymmetry in the Universe and provide a dark matter candidate. The SHiP experiment will be able to search for HNLs produced in decays of heavy mesons and travelling distances ranging between O(50 m) and tens of kilometers before decaying. We present the sensitivity of the SHiP experiment to a number of HNL's benchmark models and provide a way to calculate the SHiP's sensitivity to HNLs for arbitrary patterns of flavour mixings. The corresponding tools and data files are also made publicly available.
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| 4. |
- Ahdida, C., et al.
(författare)
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The experimental facility for the Search for Hidden Particles at the CERN SPS
- 2019
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Ingår i: Journal of Instrumentation. - : Institute of Physics Publishing (IOPP). - 1748-0221. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The Search for Hidden Particles (SHiP) Collaboration has shown that the CERN SPS accelerator with its 400 GeV/c proton beam offers a unique opportunity to explore the Hidden Sector [1-3]. The proposed experiment is an intensity frontier experiment which is capable of searching for hidden particles through both visible decays and through scattering signatures from recoil of electrons or nuclei. The high-intensity experimental facility developed by the SHiP Collaboration is based on a number of key features and developments which provide the possibility of probing a large part of the parameter space for a wide range of models with light long-lived super-weakly interacting particles with masses up to O(10) GeV/c(2) in an environment of extremely clean background conditions. This paper describes the proposal for the experimental facility together with the most important feasibility studies. The paper focuses on the challenging new ideas behind the beam extraction and beam delivery, the proton beam dump, and the suppression of beam-induced background.
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| 5. |
- Ahdida, C., et al.
(författare)
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Measurement of the muon flux from 400 GeV/c protons interacting in a thick molybdenum/tungsten target
- 2020
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 80:3
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Tidskriftsartikel (refereegranskat)abstract
- The SHiP experiment is proposed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. About 1011muons per spill will be produced in the dump. To design the experiment such that the muon-induced background is minimized, a precise knowledge of the muon spectrum is required. To validate the muon flux generated by our Pythia and GEANT4 based Monte Carlo simulation (FairShip), we have measured the muon flux emanating from a SHiP-like target at the SPS. This target, consisting of 13 interaction lengths of slabs of molybdenum and tungsten, followed by a 2.4 m iron hadron absorber was placed in the H4 400 GeV/c proton beam line. To identify muons and to measure the momentum spectrum, a spectrometer instrumented with drift tubes and a muon tagger were used. During a 3-week period a dataset for analysis corresponding to (3.27 +/- 0.07)x1011protons on target was recorded. This amounts to approximatively 1% of a SHiP spill.
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| 6. |
- Ahdida, C., et al.
(författare)
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Sensitivity of the SHiP experiment to dark photons decaying to a pair of charged particles
- 2021
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Ingår i: European Physical Journal C. - : Springer Nature. - 1434-6044 .- 1434-6052. ; 81:5
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Tidskriftsartikel (refereegranskat)abstract
- Dark photons are hypothetical massive vector particles that could mix with ordinary photons. The simplest theoretical model is fully characterised by only two parameters: the mass of the dark photon m(gamma)D and its mixing parameter with the photon, epsilon. The sensitivity of the SHiP detector is reviewed for dark photons in the mass range between 0.002 and 10 GeV. Different productionmechanisms are simulated, with the dark photons decaying to pairs of visible fermions, including both leptons and quarks. Exclusion contours are presented and compared with those of past experiments. The SHiP detector is expected to have a unique sensitivity for m. D ranging between 0.8 and 3.3(-0.5)(+0.2) GeV, and epsilon(2) ranging between 10(-11) and 10(-17).
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| 7. |
- Ahdida, C., et al.
(författare)
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Sensitivity of the SHiP experiment to light dark matter
- 2021
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :4
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Tidskriftsartikel (refereegranskat)abstract
- Dark matter is a well-established theoretical addition to the Standard Model supported by many observations in modern astrophysics and cosmology. In this context, the existence of weakly interacting massive particles represents an appealing solution to the observed thermal relic in the Universe. Indeed, a large experimental campaign is ongoing for the detection of such particles in the sub-GeV mass range. Adopting the benchmark scenario for light dark matter particles produced in the decay of a dark photon, with αD = 0.1 and mA′ = 3mχ, we study the potential of the SHiP experiment to detect such elusive particles through its Scattering and Neutrino detector (SND). In its 5-years run, corresponding to 2 · 1020 protons on target from the CERN SPS, we find that SHiP will improve the current limits in the mass range for the dark matter from about 1 MeV to 300 MeV. In particular, we show that SHiP will probe the thermal target for Majorana candidates in most of this mass window and even reach the Pseudo-Dirac thermal relic.
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| 8. |
- Ahdida, C., et al.
(författare)
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The SHiP experiment at the proposed CERN SPS Beam Dump Facility
- 2022
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Ingår i: European Physical Journal C. - : Springer Nature. - 1434-6044 .- 1434-6052. ; 82:5
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Tidskriftsartikel (refereegranskat)abstract
- The Search for Hidden Particles (SHiP) Collaboration has proposed a general-purpose experimental facility operating in beam-dump mode at the CERN SPS accelerator to search for light, feebly interacting particles. In the baseline configuration, the SHiP experiment incorporates two complementary detectors. The upstream detector is designed for recoil signatures of light dark matter (LDM) scattering and for neutrino physics, in particular with tau neutrinos. It consists of a spectrometer magnet housing a layered detector system with high-density LDM/neutrino target plates, emulsion-film technology and electronic high-precision tracking. The total detector target mass amounts to about eight tonnes. The downstream detector system aims at measuring visible decays of feebly interacting particles to both fully reconstructed final states and to partially reconstructed final states with neutrinos, in a nearly background-free environment. The detector consists of a 50m\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm { \,m}$$\end{document} long decay volume under vacuum followed by a spectrometer and particle identification system with a rectangular acceptance of 5 m in width and 10 m in height. Using the high-intensity beam of 400GeV\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\,\mathrm {GeV}$$\end{document} protons, the experiment aims at profiting from the 4x1019\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$4\times 10<^>{19}$$\end{document} protons per year that are currently unexploited at the SPS, over a period of 5-10 years. This allows probing dark photons, dark scalars and pseudo-scalars, and heavy neutral leptons with GeV-scale masses in the direct searches at sensitivities that largely exceed those of existing and projected experiments. The sensitivity to light dark matter through scattering reaches well below the dark matter relic density limits in the range from a few MeV/c2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm {\,MeV\!/}c<^>2}$$\end{document} up to 100 MeV-scale masses, and it will be possible to study tau neutrino interactions with unprecedented statistics. This paper describes the SHiP experiment baseline setup and the detector systems, together with performance results from prototypes in test beams, as it was prepared for the 2020 Update of the European Strategy for Particle Physics. The expected detector performance from simulation is summarised at the end.
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| 9. |
- Ahdida, C., et al.
(författare)
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Track reconstruction and matching between emulsion and silicon pixel detectors for the SHiP-charm experiment
- 2022
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Ingår i: Journal of Instrumentation. - : IOP Publishing. - 1748-0221. ; 17:3
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Tidskriftsartikel (refereegranskat)abstract
- In July 2018 an optimization run for the proposed charm cross section measurement for SHiP was performed at the CERN SPS. A heavy, moving target instrumented with nuclear emulsion films followed by a silicon pixel tracker was installed in front of the Goliath magnet at the H4 proton beam-line. Behind the magnet, scintillating-fibre, drift-tube and RPC detectors were placed. The purpose of this run was to validate the measurement's feasibility, to develop the required analysis tools and fine-tune the detector layout. In this paper, we present the track reconstruction in the pixel tracker and the track matching with the moving emulsion detector. The pixel detector performed as expected and it is shown that, after proper alignment, a vertex matching rate of 87% is achieved.
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| 10. |
- Milstead, David A., et al.
(författare)
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The active muon shield in the SHiP experiment
- 2017
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The SHiP experiment is designed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. An essential task for the experiment is to keep the Standard Model background level to less than 0.1 event after 2 x 10(20) protons on target. In the beam dump, around 10(11) muons will be produced per second. The muon rate in the spectrometer has to be reduced by at least four orders of magnitude to avoid muon-induced combinatorial background. A novel active muon shield is used to magnetically deflect the muons out of the acceptance of the spectrometer. This paper describes the basic principle of such a shield, its optimization and its performance.
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| 11. |
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| 12. |
- Edwards, K, et al.
(författare)
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Using Chronicle Workshop to quantify impact of context in case studies
- 2014
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Ingår i: In: Kasper Edwards & Jørgen Winkel (Eds.) Abstract book, The 8th Novo symposium: Sustainable Health Care Production Systems, Copenhagen, November 6 - 7, 2014, Technical University of Denmark..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 13. |
- Siikanen, J, et al.
(författare)
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Cyclotron-produced 68Ga from enriched 68Zn foils
- 2021
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Ingår i: Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine. - : Elsevier BV. - 1872-9800. ; 176, s. 109825-
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Tidskriftsartikel (refereegranskat)
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| 14. |
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| 15. |
- Winkel, Jörgen, 1946, et al.
(författare)
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Factors facilitating and inhibiting Value Stream Mapping processes at hospital units in three Nordic countries - A Nordic Multicenter study
- 2014
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Ingår i: O. Broberg, N. Fallentin, P. Hasle, P.L. Jensen, A. Kabel, M.E. Larsen, T.Weller (Editors). 11th International Symposium on Human Factors in Organisational Design and Management 46th Annual Nordic Ergonomics Society Conference. - 9788793130135
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- 1.Conceptual framework and Purpose In healthcare Value Stream Mapping (VSM) is a common Lean tool used to improve the efficiency of patient flows by identifying and minimizing waste (Keyte & Locher, 2004). It is a participatory tool, i.e. those affected by this type of rationalization are performing the analyses and subsequently suggesting appropriate interventions. Participation has been shown to be crucial to obtain ownership of the suggested interventions and thereby increase impact. VSM has been shown to be a powerful rationalization tool. However, the resulting interventions may imply physical work intensification and impaired psychosocial work environment. Due to this, Lean is often perceived as a “threat” by employees at hospitals (Härenstam et al 2000, personal communications). Physical and psychosocial working conditions should therefore be taken into account in the rationalization process to obtain sustainable solutions, i.e. solutions that allow for competitive performance and acceptable work environment in a long term perspective. On this background we have complemented the VSM tool by an ergonomic module assisting the users to consider also physical and psychosocial implications of the suggested interventions. This ErgoVSM tool is now evaluated in a Nordic Multicenter Study including Denmark, Iceland and Sweden (Winkel et al, 2012). The aim of this paper is to present observations that may indicate facilitating and inhibiting factors for the VSM process. 2.Methods Seven wards have used the ErgoVSM and seven the traditional VSM. Information was obtained by screening key hospital documents and interviewing participants in the VSM processes. 3.Results In Sweden one out of three wards using VSM decided not to fulfil the VSM process. On Iceland the only ward using VSM also decided not to fulfil their VSM process. The hospitals of the investigated wards using VSM in Sweden and Iceland had a strong primary focus on financial balance of the business according to key documents. Decisions on when and which value stream to analyse were made by management with little/no dialog with the employees. Work environment issues were not discussed as part of this. In addition, Iceland had a short experience of Lean, mainly based on support from McKinsey, an American global management consulting firm that focuses on solving issues of concern to senior management (http://en.wikipedia.org/wiki/McKinsey_%26_Company). Thus, they had no attention to the wellbeing to the employees and their work environment when introducing Lean. In general, the Icelandic Lean coaches had problems motivating the employees. However, they perceived a facilitated VSM process at the investigated ErgoVSM ward. Due to this, the main Lean coach decided to include work environment aspects in the VSM processes performed at other wards not part of the present Multicenter Study. Positive effects on those VSM processes were reported back to the researchers. In Denmark all three wards using VSM fulfilled their VSM process. This hospital had a long Lean experience. The main Lean coach reported process problems during their 3 initial years when using a top-down approach. Before the present project was initiated they had turned to a bottom-up initiation of the VSM processes. The Lean coach also expressed that work environment issues might be articulated as part of the VSM process. All seven wards using ErgoVSM in the 3 countries fulfilled the process. 4.Conclusion When using the Lean tool “Value Stream Mapping” it seems to be important not only to focus on efficiency but also on issues that are perceived important for the well-being of the individual employee. 5.Financial support The Nordic Council of Ministers and national grants. 6.References Härenstam A, Bejerot E, Johansson K, Leijon O, Schéele P. “Mager och god” eller ”Lean and mean”? Samband mellan organisationsförändringar och arbetsförhållanden. In: Barllöf K (Ed.) Smärtgränsen? En antologi om hälsokonsekvenser I magra organisationer. Rådet för arbetslivsforskning, pp 2000 Keyte, B., Locher, D., 2004. The Complete Lean Enterprise. Value Stream Mapping for Administrative and Office Processes. Productivity Press, New York. Winkel J, Birgisdóttir B D, Dudas K, Edwards K, Gunnarsdóttir S, Jarebrant C, Johansson Hanse J (2012). A Nordic work environment complement to Value Stream Mapping (VSM) for sustainable patient flows at hospitals – A NOVO Multicenter study. 6th NOVO Symposium: Sustainable Health Care: Continuous Improvement of Processes and Systems. Karolinska Institute, Stockholm Sweden. November 15-16, 2012, pp 58-59. ISBN: 978-91-637-2380-3
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| 16. |
- Winkel, Jörgen, 1946, et al.
(författare)
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Introduction of Lean/Value Stream Mapping at hospital units in three Nordic countries and expected impact on the working environment - A Nordic Multicenter study
- 2013
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Ingår i: International HELIX Conference 2013.
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Konferensbidrag (refereegranskat)abstract
- Conceptual framework and Purpose A recent review has documented mostly negative effects of rationalization on musculoskeletal and mental health and corresponding risk factors. This goes in particular for the healthcare sector (Westgaard & Winkel, 2011). Lean Practices are increasingly used in healthcare and Value Stream Mapping (VSM) seems to be a commonly used tool to identify and minimize waste (Keyte & Locher, 2004). The health impact of Lean varies considerably between investigations. This may to a large extend be due to differences in the operationalization of Lean (Brännmark et al, 2012). VSM is a participatory tool, i.e. those affected by this type of rationalization are performing the analyses and subsequently suggesting the interventions. Participation has been shown to be crucial to obtain ownership of the suggested interventions and thereby increased impact. On this background rationalizations based on VSM may offer a procedure that also includes working environment issues. In addition, workplaces in the Nordic countries seem to offer good opportunities for realizing a true participatory approach considering also working environment issues when rationalizing a value stream (Guðmundsson, 1993; Westgaard & Winkel, 2011). VSM has been shown to be a powerful rationalization tool in the elimination of non-value-adding tasks (non-VAT). Several studies show that non-VAT generally offer less risky physical and mental exposures (e.g. Kazmierczak et al, 2005; Østensvik et al, 2008; Palmerud et al, 2012; Jonker et al, 2013). According to this, non-VAT is usually named “the porosity of the working day” (Marx, 1867; Westgaard & Winkel, 2011; Winkel & Westgaard, 2001). Strong political demands to maximize efficiency in healthcare may thus potentially result in an excessive rationalization causing a too large reduction in porosity and thus too risky work intensification. In practice Lean is often perceived as a “threat” by employees at hospitals (Härenstam et al, 2000; many personal communications). In contrast, most Lean consultants generally describe Lean as an opportunity for improvements also in terms of the working environment (numerous personal communications). On this background an ergonomic complement to VSM, the ErgoVSM, has been developed based on existing scientific evidence and in close co-operation with Swedish industry and the healthcare sector (Jarebrant et al, 2013). The ErgoVSM also considers health issues, i.e. risk factors for musculoskeletal and mental health in addition to reduction of waste (Jarebrant et al, 2004; 2009). In this paper we present some preliminary data based on 1st line managers’ assessments of expected impact of action plans based on VSM and ErgoVSM. The presented data are retrieved from a larger NOVO Multicenter Study (Winkel et al, 2012). Design/Methodology Fourteen hospital wards in Denmark, Iceland and Sweden are investigated. Seven of these are using VSM and the remaining the ErgoVSM to improve the efficiency of their patient flows. Current and future states are assessed and action plans presented. 1st line managers are then interviewed and asked to assess expected impact of each suggested intervention in the action plan in terms of efficiency, treatment quality, physical and psychosocial working environment. So far five of the fourteen 1st line managers have been interviewed. Two of the wards have used the VSM tool and 3 the ErgoVSM tool. Results and Discussion All together 103 amendments for improved performance have been assessed in the five action plans. Eighty-one of these were assessed also to imply improvements in the working environment. Three suggestions were expected to imply a negative impact and four no impact on the working environment. Fifteen suggestions were not rated as they were decided not to be realized. Using VSM or ErgoVSM did not influence the assessment of expected impact of amendments in the action plan. The dominance of expected positive impact on the working environment of the amendments will be discussed in terms of potential bias and real opportunities. The Multicenter Study includes follow-up investigations of realized impact on the working environment as well as potential national differences between the three investigated countries (cf. Birna & Gunnarsdóttir, 2012; Edwards & Winkel, 2012; Jarebrant et al, 2012).
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