Tomography reconstruction of beams extracted from an ion source

Commissioning of the CANREB (CANadian Rare isotope facility with Electron Beam ion source) system and its associated beamlines has recently begun at TRIUMF. At the head of this beamline is an ion source used to produce stable alkaline ions with energy up to 60 keV for the CANREB system. Throughout commissioning, it is essential to have a means of verifying beam quality and ensuring that the required beam parameters along the beamline are met. This is accomplished using tomography reconstruction, which consists of taking one-dimensional scans at different projections and reconstructing an image of the beam in two dimensions using the maximum entropy algorithm. Tomography enables the visualization of the shape of the beam as well as the investigation into the possible presence of aberrations. Initially, tomography reconstruction is performed by using simulated beam profiles at the measurement locations and is then performed by using measured beam profiles. Additionally, these measurements are benchmarked by fitting the initial beam parameters in our beam optics model, and the results are presented.

Charge state breeding experiences and plans at TRIUMF

At the Isotope Separation and ACceleration (ISAC) facility at TRIUMF, an electron cyclotron resonance ion source (ECRIS) has been set up for the charge state breeding of radioactive ions. In order to reduce background from stable ions generated in the ECRIS, several measures, including changing materials for the plasma chamber and the surrounding components, have been implemented. Further reduction has been achieved by using the post-accelerator chain as a mass filter. Since the implementation of those measures in 2013, physics experiments with accelerated radioactive isotopes of Rb, Sr, K, and Mg have been performed. In most cases, a charge breeding efficiency of several percent has been achieved. With the planned expansion of the isotope production capabilities at TRIUMF within the Advanced Rare IsotopE Laboratory project, two new target stations, one using photo-fission induced by a high-power electron beam at 50 MeV and the other one using 480 MeV protons as at ISAC, will be put into operation within the next 5 yr. Additionally, a new electron beam ion source (EBIS) based charge state breeding system will be installed. Background from such a source is expected to be much lower. The drawback is that for the efficient operation of such a system, pulsed beam operation is required, which makes the installation of an additional ion buncher in front of the EBIS necessary.

A multicharge ion source (Supernanogan) for the OLIS facility at ISAC/TRIUMF

The Off-Line Ion Source (OLIS) [K. Jayamanna, D. Yuan, T. Kuo, M. MacDonald, P. Schmor, and G. Dutto, Rev. Sci. Instrum. 67, 1061 (1996); K. Jayamanna, Rev. Sci. Instrum. 79, 02711 (2008)] facility consists of a high voltage terminal containing a microwave cusp ion source, either a surface ion source or a hybrid surface-arc discharge ion source [K. Jayamanna and C. Vockenhuber, Rev. Sci. Instrum. 79, 02C712 (2008)], and an electrostatic switch that allows the selection of any one of the sources without mechanical intervention. These sources provide a variety of +1 beams up to mass 30 for Isotope Separator and ACcelerator (ISAC) [R. E. Laxdal, Nucl. Instrum. Methods Phys. Res. B 204, 400 (2003)] experiments, commissioning the accelerators, setting up the radioactive experiments, and for tuning the beam lines. The radio frequency quadrupole (RFQ) [M. Marchetto, Z. T. Ang, K. Jayamanna, R. E. Laxdal, A. Mitra, and V. Zvyagintsev, Eur. Phys. J. Spec. Top. 150, 241 (2005)] injector accelerator is a constant velocity machine designed to accept only 2 keV/u and the source extraction energy is limited to 60 kV. Further stripping is then needed downstream of the RFQ to inject the beam into the drift tube linac [M. Marchetto, Z. T. Ang, K. Jayamanna, R. E. Laxdal, A. Mitra, and V. Zvyagintsev, Eur. Phys. J. Spec. Top. 150, 241 (2005)] accelerator that requires A/q up to 6. Base on this constraints a multicharge ion source capable to deliver beams above mass 30 with A/q up to 6 was needed in order to reach full capability of the ISAC facility. A Supernanogan [C. Bieth et al., Nucleonika 48, S93 (2003)] multicharge ion source was then purchased from Pantechnik and was installed in the OLIS terminal. Commissioning and performance of the Supernanogan with some results such as emittance dependence of the charge states as well as charge state efficiencies are presented.

Off-line ion source terminal for ISAC at TRIUMF

The off-line ion source (OLIS) terminal consists of a microwave cusp ion source, either a surface ion source or a hybrid surface-arc discharge ion source and an electrostatic switch that allows selecting any one of the sources without mechanical intervention. These sources provide variety of beams to ISAC experiments, for commissioning the accelerators, for setting up the radioactive experiments, and for tuning the beam lines. The microwave ion source has been operational since 1995 and provides singly and doubly charged beams from various stable isotopes for many ISAC experiments at high and low energy areas. Originally its prime goal was to provide beams from gaseous elements, but later two ovens and a sputtering system were added in order to provide beams from liquids and from solids. The surface ion source installed in 2002 can provide low energy spread beams from alkali and semialkali elements. It also has three separate ovens and an ionizer. Therefore, it can provide three different temperature regions simultaneously to provide different beams to ISAC. It is mainly used for laser spectroscopy experiments and other experiments, which require a finite beam quality. A hybrid surface-arc discharge ion source was also developed and installed in order to meet specific demands from experiments. This source terminal is now automated for start up and for mass selection. It is capable of providing stable beams for months without maintenance and it is also capable of providing negative ion beams if required. To date, over 40 different isotopes including many rear isotopes were delivered to various experiments from the OLIS source terminal. Performances of the ion sources and some of the results are discussed.

High-rate dissolved air flotation for water treatment

This paper presents the results of an experimental investigation about the performance of a horizontal flow high-rate pilot scale Dissolved Air Flotation (HRDAF) unit containing inclined parallel plates for treating a coloured and low turbidity raw water. Experiments were performed with the DAF unit in order to verify the influence on flotation of: (i) the water velocity (Vh) between the plates, in the range 18 to 96.5 cm.min-1 with corresponding Reynolds numbers between 240 and 1060; (ii) the supplied air (S*) value ranging from 2.2 to 8.5 g of air/m3 of water; (iii) the angle of the plates (60 degrees or 70 degrees). The best pilot plant operational condition was obtained applying only 4.0 g/m3 (S*) with Vh around 18 cm.min-1 for treatment of water coagulated with a Al2(SO4)3 dosage of 40 mg.l-1. In these conditions, the unit presented very good removal efficiencies of colour (90%, residual of 10 uC), turbidity (88%, residual of 0.8 NTU) and TSS (94%, residual of 1.8 mg.l-1). Furthermore, the unit could operate at higher Vh values up to 76 cm.min-1 and still present good results. The DAF unit thus behaved as a high rate unit presenting good performance with low air requirement.

Daily gastric pH in controls and in duodenal ulcer patients: basal condition and response to treatment

Gastric pH was monitored, by means of a computerized system, in healthy controls (C) and in patients with active duodenal ulcer (ADU) and inactive duodenal ulcer (IDU). The test was performed before treatment and during administration of a single dose of ranitidine 150 mg, cimetidine 400 mg, and pirenzepine 50 mg, in random sequence at 12-h intervals, (10 am, 10 pm). Under basal conditions, progressively lower median pH values were detected in ADU and IDU patients, compared with controls. A significant difference was found between C and ADU during daytime (1.38 vs. 0.85), nighttime (1.29 vs. 0.81), and 24 h (1.35 vs. 0.81) and between C and IDU during 24 h (1.35 vs. 1.11). However, no statistical difference was observed between patients with active and inactive ulcer disease. Administration of ranitidine and cimetidine significantly increased gastric pH during nighttime but not during daytime. Ranitidine, at the doses studied, proved to be more potent than cimetidine in suppressing gastric acidity. Gastric pH was unaffected by pirenzepine in most cases.

Ultrasonic monitoring of Wirsung duct following secretin in controls and in chronic pancreatitis patients

Ultrasonic monitoring of the pancreas following secretin stimulation has shown to cause a marked dilatation of Wirsung duct; whether this phenomenon is due to the stimulation of pancreatic secretion and/or to the effect of secretin on the sphincter of Oddi (SO) motility is unknown. In the present study pancreatic scan after secretin was performed in 11 patients with nonpancreatic diseases after premedication with glucagon (inhibition of both pancreatic secretion and SO motility) or tyropramide (inhibition of SO motor function) and in patients with different degrees of pancreatic insufficiency. Serum immunoreactive trypsinogen (IRT) levels were measured in all the subjects during the test. Premedication with glucagon completely abolished both Wirsung enlargement and serum IRT increase, while tyropramide significantly reduced, but did not abolish, the response to secretin. These results suggest that both stimulation of pancreatic secretion and the increase of SO pressure are prerequisites for a full-blown occurrence of the secretin-induced modifications of Wirsung. Within chronic pancreatitis patients, the response to secretin was exaggerated in those with a still preserved pancreatic function and it was lacking in those with severe pancreatic insufficiency.

Comparison of ranitidine and sucralfate in the long-term treatment of duodenal ulcer

We evaluated long-term treatment with either ranitidine (R) or sucralfate (S) in the prevention of duodenal ulcer recurrences. Fifty-nine patients with healed ulcers were randomly allocated to maintenance treatment with 150 mg R nightly or 2 g/day S. By using a life table analysis, the calculated probable remission rates at 4, 8, and 12 months were 90, 85, and 53% with R, respectively, and 62, 62, and 53% with S, respectively. These differences were not significant at any interval. In both groups ulcer relapse was independent of sex, smoking habit, and alcohol and coffee consumption, whereas a history longer than 5 years was significantly related to a higher probability of recurrence. No relevant clinical or biochemical side effects were encountered with either drug, but compliance rate was higher in the R group. R and S are equally effective in preventing duodenal ulcer relapse over a 1-year period of maintenance treatment, although R proved to be more effective in preventing early relapse.

Evocative test of serum pancreatic enzymes to bombesin in chronic pancreatitis

The levels of serum immunoreactive trypsinogen and P-isoamylase in response to Bombesin intravenous infusion were evaluated in 25 controls, 18 patients with documented chronic pancreatitis, and nine subjects with nonpancreatic gastroenterological diseases. Mean immunoreactive trypsinogen peak values were significantly higher in controls and gastroenterological diseases than in chronic pancreatitis, but there was marked overlap in individual values between the three groups. As for P-isoamylase, a statistical difference was detected only between mean peak concentrations of control versus chronic pancreatitis. Integrated responses for both enzymes did not result in a better discrimination between controls, chronic pancreatitis, and gastroenterological diseases. This study confirms that evocative tests are of limited value in the diagnosis of pancreatic disease.

A computer-assisted technique for long-term gastric pH monitoring

A computer-assisted technique for prolonged gastric pH monitoring has been developed using a personal computer. Segments of signal from several studies performed in controls and on patients with duodenal ulcers were chosen for comparison between manual and digital pH readings; no significant difference was detected. In clinical practice this system might provide an additional tool in the diagnostic and therapeutic treatment of peptic ulcer disease.

Diagnostic accuracy of serum cationic trypsinogen estimation for pancreatic diseases

Serum immunoreactive trypsinogen (IT) levels were measured in 479 normal controls and in 604 patients (510 with nonpancreatic diseases and 94 with pancreatic diseases) in order to evaluate the distribution of IT values in the control population and the accuracy of the assay in the diagnosis of pancreatic diseases. It concentrations were normally distributed in the healthy population; children showed mean IT values significantly lower than adults. The sensitivity, specificity, and predictive value of a positive and negative result in diagnosing acute or chronic pancreatitis were evaluated vs normals and vs normals plus all patients. With an IT value higher than 80 ng/ml, the likelihood that a patient is not affected by acute pancreatitis is less than 5%. An IT value lower than 9 ng/ml detected 44% of chronic pancreatitis and was related to a 52% probability of such a condition. The 48% false positive results also include patients with pancreatic tumor (31% of cases), so that the chance of finding reduced IT levels in subjects without pancreatic damage drops to 17%. In view of the low prevalence of pancreatic diseases, IT assay should not be taken into consideration as a diagnostic screening test in the general population and its use should be limited to a hospitalized population.