Activation and radiation damage in the environment of hadron accelerators

A component which suffers radiation damage usually also becomes radioactive, since the source of activation and radiation damage is the interaction of the material with particles from an accelerator or with reaction products. However, the underlying mechanisms of the two phenomena are different. These mechanisms are described here. Activation and radiation damage can have far-reaching consequences. Components such as targets, collimators, and beam dumps are the first candidates for failure as a result of radiation damage. This means that they have to be replaced or repaired. This takes time, during which personnel accumulate dose. If the dose to personnel at work would exceed permitted limits, remote handling becomes necessary. The remaining material has to be disposed of as radioactive waste, for which an elaborate procedure acceptable to the authorities is required. One of the requirements of the authorities is a complete nuclide inventory. The methods used for calculation of such inventories are presented, and the results are compared with measured data. In the second part of the paper, the effect of radiation damage on material properties is described. The mechanism of damage to a material due to irradiation is described. The amount of radiation damage is quantified in terms of displacements per atom. Its calculation and deficiencies in explaining and predicting the changes in mechanical and thermal material properties are discussed, and examples are given.Comment: 27 pages, contribution to the CAS - CERN Accelerator School: Course on High Power Hadron Machines; 24 May - 2 Jun 2011, Bilbao, Spai

Po-production in lead: A benchmark between Geant4, FLUKA and MCNPX

On the last SATIF a comparison between the measured activities of the polonium isotopes Po-208, Po-209 and Po-210 and the simulated results using MCNPX2.7.0 was presented. The lead samples were cut from the SINQ spallation target at the Paul Scherrer Institut (PSI) and irradiated in 2000/2001 by 575 MeV protons. The Po-isotopes were separated using radiochemical methods by the group of D. Schumann at PSI and measured. Choosing the default model in MCNPX, Bertini-Dresner, the prediction underestimated the measured activities by up to several orders of magnitude. Therefore the Li\`ege intranuclear-cascade model (INCL4.6) coupled to the de-excitation model ABLA07 were implemented into MCNPX2.7.0 and very good agreement was found to the measurement. The reason for the disagreement was traced back to a suppression of alpha reactions on the lead isotopes leading to Po and neglecting the triton capture on Pb-208, which leads to Pb-210 and decays into Po-210 with a much longer life time (22.3 years) than the decay of Po-210 itself (138 days). The prediction of the Po-isotope activities turns out to be a sensitive test for models and codes as it requires the accurate treatment of reaction channels not only with neutrons, protons and pions but also with alphas and tritons, which are not considered in intra-nuclear cascade models of the first generation. Therefore it was decided to perform a benchmark by comparing the results obtained with MCNPX2.7.0 using INCL4.6/ABLA07 to the predictions of FLUKA and Geant4. Since the model of the SINQ spallation source requires an elaborate geometry a toy model was setup. The toy model has a simplified geometry preserving the main features of the original geometry. The results for the activities of the three Po-isotopes and Pb-210 as well as the energy spectra for alphas and tritons obtained with the three particle transport Monte Carlo codes are presented.Comment: 15 pages, 11 figures, Presented paper at the 13th Meeting of the task-force on Shielding aspects of Accelerators, Targets and Irradiation Facilities (SATIF-13), HZDR, October 10-12, 2016, Dresden, German

Voluntary sports programs for individuals with mental health disorders: The trainer’s view

There is strong evidence that physical activities (PAs) are an important factor in increasing and maintaining mental health as well as in preventing relapse after mental health disorders. Physical activity is an important part of the treatment program in psychiatric hospitals. However, when individuals with mental health disorders (IMHD) leave the hospitals in Switzerland (CH), there are few possibilities to do physical activity in a given setting. One of them are voluntary sports groups for individuals with mental health disorders (SGPSY), which have been growing continuously in CH since 2016. Yet, little is known about these groups and their training settings. Therefore, the present study explores challenges, barriers, and enablers for participation in SGPSY from the point of view of the trainers of these groups. Additionally, as the sustainable implementation of SGPSY relies on the trainer, the study aims to identify reasons/motivations as well as the personality characteristics of the SGPSY trainers. Semi-structured interviews were conducted with 15 trainers of SGPSY in CH during spring 2022. Interviews were audiotaped, transcribed, and analyzed using thematic analysis in nVivo. Participants identified several intrapersonal (lack of motivation and fitness, mood problems, etc.), interpersonal (conflicts between participants), and structural barriers (time/location) that hinder IMHD from participating in SGPSY. The participating trainer reported that trainer might be helpful in overcoming the barriers by supporting IMHD as enablers. They rate social skills to be essential for the successful management and organization of SGPSY, as well as the ability to set boundaries to protect one’s private life and sports skills expertise. The reasons for their engagement as trainers of SGPSY were the satisfaction of doing sports with IMHD and to improve the physical activities habits of IMHD. The findings of the study highlight the need to upskill the trainers of SGPSY in order to improve recruitment of the future trainers of SGPSY by focusing on the assessment of appropriate personality characteristics of trainers and their motives. Additionally, these findings should be integrated in the educational materials of Swiss disabled sports systems. Further research should validate the results from SGPSY participants’ point of view

Radiochemical analysis of concrete samples from accelerator waste

For the decommissioning and disposal of shielding concrete from accelerator facilities, the Swiss Authorities require information on the radionuclide inventory. Besides the easy-to-measure γ-emitters 152Eu, 60Co, 44Sc, 133Ba, 154Eu, 134Cs, 144Ce, 22Na, also long-lived radionuclides emitting α- or β-radiation like 129I, 10Be, 36Cl, 239/240Pu and 238U have to be studied in order to obtain an overview to which extent they are produced and whether they represent a safety issue. In this study, we present the chemical separation and determination of selected radionuclides in shielding concrete from two different positions in the accelerator facilities at the Paul Scherrer Institute (PSI), the BX2 station, which was shut down in 1998, and the environment of the target M station, where the samples were taken in 1985 during reconstruction. The results of the measurements show that in no case the radionuclide content represents a safety risk. The components can be decommissioned corresponding to the Swiss safety regulation

Improved radiative corrections for (e,e'p) experiments - A novel approach to multi-photon bremsstrahlung

Radiative processes lead to important corrections to (e,e'p) experiments. While radiative corrections can be calculated exactly in QED and to a good accuracy also including hadronic corrections, these corrections cannot be included into data analyses to arbitrary orders exactly. Nevertheless consideration of multi-photon bremsstrahlung above the low-energy cut-off is important for many (e,e'p) experiments. To date, higher-order bremsstrahlung effects concerning electron scattering experiments have been implemented approximately by employing the soft-photon approximation (SPA). In this paper we propose a novel approach to multi-photon emission which partially removes the SPA from (e,e'p) experiments. In this combined approach one hard photon is treated exactly; and additional softer bremsstrahlung photons are taken into account resorting to the soft-photon approximation. This partial removal of the soft-photon approximation is shown to be relevant for the missing-energy distribution for several kinematic settings at MAMI and TJNAF energies.Comment: 10 pages, 21 figure

Voluntary sport programs for individuals with mental health disorders: The trainer’s and participant’s view

Introduction There is strong evidence that physical activities are important in increasing and maintaining mental health as well as in preventing relapse after mental health disorders (Schulz et al., 2011). Physical activity is an integral part of the treatment program in psychiatric hospitals in Switzerland (CH; Brand et al., 2016). However, after discharge from the hospital in CH, there are insufficient opportunities to engage in physical activity for individuals with mental health disorders (IMHD). To close this gap, voluntary sports groups (VSG) for IMHD have been growing in Switzerland since 2016, mainly organized by the PluSport Umbrella Organization of Swiss Disabled Sports (Kiselev & Loosli, 2019). Yet, little is known about these VSG and their training settings. The perspectives of IMHD and trainers of these groups as well as the perceived barriers and facilitators for participating for IMHD have neither been assessed nor included in the design of sports programs. Therefore, two studies aimed to explore the point of view of the IMHD (first study) and the trainers of these groups (second study) on challenges, barriers, and facilitators for IMHD regarding participation in VSG for IMHD. Additionally, given the crucial role of the trainers in the training process and the importance of their interpersonal characteristics, both studies aimed to identify reasons/motivations and proper personality characteristics of the VSG trainers from the interviewees’ perspective. Methods Both studies consisted of 15 semi-structured interviews each (with participants (1st study) and with trainers (2nd study) of VSG for IMHD). The results were analyzed using thematic analysis using Nvivo (Guest et al., 2012). Results Several training facilitators and trainers’ characteristics supporting the participation of the IMHD in VSG for IMHD were named by interviewees (e.g., offer-specific, emotional, rational motives, social skills of the trainers, and ability to set boundaries). At the same time, respondents reported several barriers as possible inhibitors for the participation of IMHD in VSG for IMHD (e.g., intrapersonal, structural, offer-specific, interpersonal and socio-cultural). Within the interviews, IMHD described predominantly positive perceived outcomes from participating in VSG for IMHD. On the other side, trainers of VSG for IMHD highlighted the satisfaction of doing sports with IMHD and of the contribution to improving the physical activity habits of IMHD as the main factors for their commitment as coaches (Baumberger et al., under review; Epiney et al., 2023). Discussion/Conclusion IMHD benefit socially, physically, and psychologically from participating in VSG for IMHD. However, participation is associated with barriers that need to be minimized in the future to make participation more accessible. Furthermore, the findings suggest improving the recruitment of future trainers of VSG for IMHD by focusing on assessing the appropriate personality characteristics of trainers and their motives. Additionally, findings should be integrated into the educational materials of Swiss disabled sports systems to ensure the proper upskilling of the new and present trainers of VSG for IMHD and ensure the quality and attractiveness of these groups for the target population . Finally, a large-scale survey is necessary to validate the results among the population. References Baumberger, C., Wieber, F., Pauli, C., Loosli, D., Kleim, B., & Kiselev, N. (under review). Active bodies - Active minds? A deep dive into the voluntary sports programs for individuals with psychiatric disorders in Switzerland: Participants view. BMC Public Health. Brand, S., Colledge, F., Beeler, N., Pühse, U., Kalak, N., Sadeghi Bahmani, D., Mikoteit, T., Holsboer-Trachsler, E., & Gerber, M. (2016). The current state of physical activity and exercise programs in German-speaking, Swiss psychiatric hospitals: Results from a brief online survey. Neuropsychiatric Disease and Treatment, 12, 1309-1317. https://doi.org/10.2147/NDT.S107313 Epiney, F., Wieber, F., Loosli, D., Znoj, H., & Kiselev, N. (2023). Voluntary sports programs for individuals with mental health disorders: The trainer’s view. Plos one, 18(10), Article e0290404. https://doi.org/10.1371/journal.pone.0290404 Guest, G., MacQueen, K., & Namey, E. (2012). Applied Thematic Analysis. SAGE. https://doi.org/10.4135/9781483384436 Kiselev, N., & Loosli, D. (2019). Kann ich mitmachen? Behinderten- und Rollstuhlsportclubs in der Schweiz und der Zugang zum Behinderten- und Rollstuhlsport [Disabled and wheelchair sports clubs in Switzerland and access to disabled and wheelchair sports]. Schweizerische Zeitschrift für Heilpädagogik, 25(5-6), 13-20. Schulz, K. H., Meyer, A., & Langguth, N. (2011). Körperliche Aktivität und psychische Gesundheit [Physical activity and mental health]. Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz, 55(1), 55-65. https://doi.org/10.1007/s00103-011-1387-

Structural and socio-cultural barriers to accessing mental healthcare among Syrian refugees and asylum seekers in Switzerland.

Background: Due to their experiences of major stressful life events, including post-displacement stressors, refugees and asylum seekers are vulnerable to developing mental health problems. Yet, despite the availability of specialized mental health services in Western European host countries, refugees and asylum seekers display low mental healthcare utilization. Objective: The aim of this study was to explore structural and socio-cultural barriers to accessing mental healthcare among Syrian refugees and asylum seekers in Switzerland. Method: In this qualitative study, key-informant (KI) interviews with Syrian refugees and asylum seekers, Swiss healthcare providers and other stakeholders (e.g. refugee coordinators or leaders) were conducted in the German-speaking part of Switzerland. Participants were recruited using snowball sampling. Interviews were audiotaped and transcribed, and then analysed using thematic analysis, combining deductive and inductive coding. Results: Findings show that Syrian refugees and asylum seekers face multiple structural and socio-cultural barriers, with socio-cultural barriers being perceived as more pronounced. Syrian key informants, healthcare providers, and other stakeholders identified language, gatekeeper-associated problems, lack of resources, lack of awareness, fear of stigma and a mismatch between the local health system and perceived needs of Syrian refugees and asylum seekers as key barriers to accessing care. Conclusions: The results show that for Syrian refugees and asylum seekers in Switzerland several barriers exist. This is in line with previous findings. A possible solution for the current situation might be to increase the agility of the service system in general and to improve the willingness to embrace innovative paths, rather than adapting mental healthcare services regarding single barriers and needs of a new target population

Feasibility and acceptability of Problem Management Plus (PM+) among Syrian refugees and asylum seekers in Switzerland: a mixed-method pilot randomized controlled trial

Background: Syrian refugees in Switzerland face several barriers in accessing mental health care. Cost-effective psychological interventions are urgently needed to meet the mental health needs of refugees. Problem Management Plus (PM+) is an evidence-based, psychological intervention delivered by trained non-specialist ‘helpers’. Objective: To assess the feasibility and acceptability of PM+ among Syrian refugees in Switzerland. Methods: We conducted a single-blind pilot randomized controlled trial (RCT) with Syrian refugees impaired by psychological distress (K10 > 15 and WHODAS 2.0 > 16). Participants were randomized to PM+ or Enhanced Treatment As Usual (ETAU). Participants were assessed at baseline, and 1 week and 3 months after the intervention, and completed measures indexing mental health problems and health care usage. Semi-structured interviews were conducted with different stakeholders. Results: N = 59 individuals were randomized into PM+ (n = 31) or ETAU (n = 28). N = 18 stakeholders were interviewed about facilitators and barriers for the implementation of PM+. Retention rates in the trial (67.8%) and mean intervention attendance (M = 3.94 sessions, SD = 1.97) were high. No severe events related to the study were reported. These findings indicate that the trial procedures and PM+ were feasible, acceptable and safe. Conclusions: The findings support the conduct of a definitive RCT and show that PM+ might have the potential to be scaled-up in Switzerland. The importance, as well as the challenges, of implementing and scaling-up PM+ in high-income countries, such as Switzerland, are discussed

Induced radioactivity studies of the shielding and beamline equipment of the high intensity proton accelerator facility at PSI

The Paul Scherrer Institute (PSI) is the largest national research center in Switzerland. Its multidisciplinary research is dedicated to a wide ↓eld in natural science and technology as well as particle physics. The High Intensity Proton Accelerator Facility (HIPA) has been in operation at PSI since 1974. It includes an 870 keV Cockroft-Walton pre-accelerator, a 72 MeV injector cyclotron as well as a 590 MeV ring cyclotron. The experimental facilities, the meson production graphite targets, Target E and Target M, and the spallation target stations (SINQ and UCN) are used for material research and particle physics. In order to ful↓ll the request of the regulatory authorities and to be reported to the regulators, the expected radioactive waste and nuclide inventory after an anticipated ↓nal shutdown in the far future has to be estimated. In this contribution, calculations for the 20 m long beamline between Target E and the 590 MeV beam dump of HIPA are presented. The ↓rst step in the calculations was determining spectra and spatial particle distributions around the beamlines using the Monte-Carlo particle transport code MCNPX2.7.0 [1]. To perform the analysis of the MCNPX output and to determine the radionuclide inventory as well as the speci↓c activity of the nuclides, an activation script [2] using the FISPACT10 code with the cross sections from the European Activation File (EAF2010) [3] was applied. The speci↓c activity values were compared to the currently existing Swiss exemption limits (LE) [4] as well as to the Swiss liberation limits (LL) [5], becoming e↑ective in the near future. The obtained results were used to estimate the total volume of the radioactive waste produced at HIPA and have to be reported to the Swiss regulatory authorities. The comparison of the performed calculations to measurements is discussed as well