Chemical Sciences: A Manual for CSIR-UGC National Eligibility Test for Lectureship and JRF/RFQ Beam Coolers

Despite its long history, high-sensitivity high-accuracy mass measurements of atomic nuclei continue to be very important areas of research for many branches of physics. Not only do these measurements provide us with a better understanding of nuclear structures and nuclear forces but they also offer insight into how matter behaves in some of Nature’s harshest environments. At facilities such as ISOLDE at CERN and TRIUMF in Vancouver, for instance, measurement techniques are now being extended to short-lived radionuclei that only occur naturally in the interior of exploding stars. Their short half-lives and very low production rates at even the most powerful facilities require the very highest in sensitivity of such measurements. Penning traps, the central element in modern high-accuracy high-sensitivity mass measurement installations, enable measurements of accuracies approaching 1 part in 10^11 on single ions. However, to achieve this Penning traps must have the ion to be measured delivered to it very precisely and with certainty that it is indeed the desired ion. This imposes severe requirements on the apparatus that must take the atomic nucleus out of the target in which it has been created, sort it from the myriad of other ions that are emitted from the target and then direct it so that it can be captured in the measurement trap. Cooling these ion beams, particularly radioactive ion beams, has been shown to drastically improve the accuracy and sensitivity of mass measurements by reducing the phase space of the ion collections in question. Using a light neutral background gas, typically helium, charged particles originating from on-line mass separators undergo a number of soft collisions with the background gas molecules resulting in fractional losses of the ions’ kinetic energy and a reduction of the ion ensemble’s overall energy. In order for this to be effective however, the ions need to be contained using transverse radiofrequency quadrupole (RFQ) electric fields during the collisional cooling process (also known as buffer gas cooling). These RFQ coolers operate on the same principles as quadrupole ion traps and have been shown to be particularly well suited for buffer gas cooling given their capacity for total confinement of ions having a large dispersion of velocities, corresponding to kinetic energies up to tens of electron volts. A number of the RFQ coolers have already been installed at research facilities around the world and a list of their characteristics can be found below. + RFQ Coolers Around the World Name Input Beam Input Emittance Cooler Length R0 RF Voltage, Freq, DC Mass Range Axial Voltage Pressure Output Beam Qualities Images Colette M. Sewtz, C. Bachelet, N. Chauvin, C. Guénaut, E. Leccia, D. Le Du and D. Lunney Deceleration and cooling of heavy ion beams: The COLETTE project Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 240 p. 55-60 2005 Cyril Bachelet Mesure de Masse de Noyaux à Halo et Refroidissement de Faisceaux avec l'Expérience Mistral PhD Thesis Université Paris XI, France 2004 60 keV ISOLDE beam decelerated to ≤ 10 eV ~ 30 π-mm-mrad 504 mm (15 segments, electrically isolated) 7 mm Freq : 450 – 700 kHz -- 0.25 V/cm 0.01 mbar He Reaccelerated to up to 59.99 keV with long. energy spread ~10 eV COLETTE1 COLETTE2 LPC Cooler Guillaume Darius Etude et Mise en oeuvre d'un Dispositif pour la Mesure de Paramètre de Correlation Angulaire dans la Désintégration du Noyau Hélium 6 PhD Thesis Université de Caen / Basse-Normandie, France 2004 SPIRAL type beams Up to ~ 100 π-mm-mrad 468 mm (26 segments, electrically isolated) 15 mm RF : up to 250 Vp, Freq : 500 kHz – 2.2 MHz -- -- up to 0.1 mbar -- LPC1 LPC2 SHIPTRAP Cooler S. Rahaman, M. Block, D. Ackermann, D. Beck, A. Chaudhuri, S. Eliseev, H. Geissel, D. Habs, F. Herfurth, F.P. Heßberger et al. On-line commissioning of SHIPTRAP International Journal of Mass Spectrometry 251 p. 146-151 2006 Jens Dilling Direct Mass Measurements on Exotic Nuclei with SHIPTRAP and ISOLTRAP PhD Thesis University of Heidelberg, Germany 2001 Daniel Rodriguez Rubiales An RFQ Buncher for Accumulation and Cooling of Heavy Radionuclides at SHIPTRAP and High Precision Mass Measurements on Unstable Kr Isotopes at ISOLTRAP PhD Thesis University of Valencia, Spain 2001 SHIP type beams 20-500 keV/A -- 1140 mm (29 segments, electrically isolated) 3.9 mm RF: 30-200 Vpp, Freq: 800 kHz – 1.2 MHz up to 260 amu Variable: 0.25 – 1 V/cm ~ 5×10-3 mbar He -- SHIPTRAP1 SHIPTRAP2 JYFL Cooler A. Jokinen, J. Huikari, A. Nieminen and J. Äystö The first cooled beams from JYFL ion cooler and trap project Nuclear Physics A 701 p. 557-560 2002 Arto Nieminen Manipulation of Low-Energy Radioactive Ion Beams With an RFQ Cooler; Applications to Collinear Laser Spectroscopy PhD Thesis University of Jyväskylä, Jyväskylä, Finland 2002 IGISOL type beam at 40 keV Up to 17 π-mm-mrad 400 mm (16 segmentes) 10 mm RF: 200 Vp, Freq: 300 kHz – 800 kHz -- ~1 V/cm ~0.1 mbar He ~3 π-mm-mrad, Energy spread < 4 eV JYFL1 JYFL2 JYFL3 MAFF Cooler J. Szerypo, D. Habs, S. Heinz, J. Neumayr, P. Thirolf, A. Wilfart and F. Voit MAFFTRAP: ion trap system for MAFF Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 204 p. 512-516 2003 30 keV beam decelerated to ~100 eV -- 450mm 30mm RF: 100 –150 Vpp, Freq: 5 MHz -- ~0.5 V/cm ~0.1 mbar He energy spread = 5 eV, Emittance @ 30keV: from = 36 π-mm-mrad to eT = 6 π-mm-mrad -- ORNL Cooler Y. Liu, J.F. Liang G.D. Alton, J.R. Beene, Z. Zhou, H. Wollnik Collisional Cooling of Negative-Ion Beams Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 187 p. 117-131 2002 20-60 keV negative RIBs decelerated to <100 eV ~50 π-mm-mrad (@ 20 keV) 400 mm 3.5 mm RF: ~400 Vp, Freq: up to 2.7 MHz -- up to ±5 kV on tapered rods ~0.01 mbar Energy spread ~2 eV ORNL1 ORNL2 ORNL3 LEBIT Cooler G. Bollen, S. Schwarz, D. Davies, P. Lofy, D. Morrissey, R. Ringle, P. Schury,T. Sun, L. Weissman Beam cooling at the low-energy-beam and ion-trap facility at NSCL/MSU Nuclear Instruments and Methods in Physics Research A 532 p. 203–209 2004 5 keV DC beams -- -- -- -- -- -- ~1×x10−1 mbar He (high-pressure section) -- LEBIT1 LEBIT2 LEBIT3 ISCOOL I. Podadera Aliseda, T. Fritioff, T. Giles, A. Jokinen, M. Lindroos and F. Wenander Design of a second generation RFQ Ion Cooler and Buncher (RFQCB) for ISOLDE Nuclear Physics A 746 p. 647-650 2004 Ivan Podadera Aliseda New Developments on Preparation of Cooled and Bunched Radioactive Ion Beams at ISOL-Facilities: The ISCOOL Project and Rotating-Wall Cooling PhD Thesis CERN, Geneva, Switzerland 2006 60 keV ISOLDE beam up to 20 π-mm-mrad 800 mm (using segmented DC wedge electrodes) 20 mm RF: up to 380 V, Freq: 300 kHz - 3MHz 10-300 amu ~0.1V/cm 0,01 - 0,1 mbar He -- ISCOOL1 ISCOOL2 ISCOOL3 ISCOOL4 ISOLTRAP Cooler T. J. Giles, R. Catherall, V. Fedosseev, U. Georg, E. Kugler, J. Lettry and M. Lindroos The high resolution spectrometer at ISOLDE Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 204 p. 497-501 2003 60 keV ISOLDE beam -- 860 mm (segmented) 6 mm RF: ~125 Vp, Freq: ~1 MHz. -- -- ~2×10-2 mbar He elong ≈ 10 eV us, etrans ≈ 10p mm mrad. ISOLTRAP1 ISOLTRAP2 TITAN RFCT J. Dilling, P. Bricault, M. Smith, H. -J. Kluge and TITAN collaboration The proposed TITAN facility at ISAC for very precise mass measurements on highly charged short-lived isotopes Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 204 Pages 492-496 2003 continuous 30–60 keV ISAC beam -- -- -- RF: 1000 Vpp, Freq: 300 kHz - 3 MHz -- -- -- 6 π-mm-mrad at 5 keV extraction energy TITAN1 TITAN2 TITAN3 TRIMP Cooler Emil Traykov Production of Radioactive Beams for Atomic Trapping PhD Thesis University of Groningen, The Netherlands 2006 TRIMP beams -- 660 mm (segmented) 5 mm RF= 100 Vp, Freq.: up to 1.5 MHz 6 < A < 250 -- up to 0.1 mbar -- TRIMP1 TRIMP2 TRIMP3 SPIG Leuven -- -- 124 mm (sextuple rod structure) 1.5 mm RF= 0-500 Vpp, Freq.: 4.7 MHz -- -- -- -- -- Argonne CPT -- -- -- -- -- -- -- -- -- -- SLOWRI cooler -- -- 600 mm (segmented sextuple rod structure) 8 mm RF= 400 Vpp, Freq.: 3.6 MHz -- -- ~10 mbar He -- -- -- -- -- -- -- -- -- -- -- -- -- References Further Reading SHIPTRAP collaboration, J. Schönfelder, D. Ackermann, H. Backe, G. Bollen, J. Dilling, A. Dretzke, O. Engels, J. Estermann, D. Habs, S. Hofmann, F. P. Hessberger, H. -J. Kluge, W. Lauth, W. Ludolphs, M. Maier, G. Marx, R. B. Moore, W. Quint, D. Rodriguez, M. Sewtz, G. Sikler, C. Toader and Chr. Weber SHIPTRAP—a capture and storage facility for heavy radionuclides at GSI Nuclear Physics A 701 p. 579-582 2002 G. Sikler, D. Ackermann, F. Attallah, D. Beck, J. Dilling, S. A. Elisseev, H. Geissel, D. Habs, S. Heinz, F. Herfurth et al. First on-line test of SHIPTRAP Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 204 p. 482-486 2003 J.B. Neumayr, L. Beck, D. Habs, S. Heinz, J. Szerypo, P.G. Thirolf, V. Varentsov, F. Voit, D. Ackermann, D. Beck et al. The ion-catcher device for SHIPTRAP Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 244 p. 489-500 2006 J. Szerypo, A. Jokinen, V. S. Kolhinen, A. Nieminen, S. Rinta-Antila and J. Äystö Penning trap at IGISOL Nuclear Physics A 701 p. 588-591 2002 T. Faestermann, W. Assmann, L. Beck, H. Bongers, W. Carli, M. Groß, R. Großmann, D. Habs, P. Hartung, S. Heinz et al. The Munich Accelerator for Fission Fragments - MAFF Nuclear Physics A 746 p. 22-26 2004 D. Habs, M. Groß, W. Assmann, F. Ames, H. Bongers, S. Emhofer, S. Heinz, S. Henry, O. Kester, J. Neumayr et al. The Munich accelerator for fission fragments MAFF Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 204 p. 739-745 2003 F. Herfurth, J. Dilling, A. Kellerbauer, G. Bollen, S. Henry, H. -J. Kluge, E. Lamour, D. Lunney, R. B. Moore, C. Scheidenberger et al. A linear radiofrequency ion trap for accumulation, bunching, and emittance improvement of radioactive ion beams Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 469 p. 254-275 2001 S. Schwarz, G. Bollen, D. Lawton, A. Neudert, R. Ringle, P. Schury and T. Sun A second-generation ion beam buncher and cooler Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 204 p. 474-477 2003 J. Clark, R. C. Barber, C. Boudreau, F. Buchinger, J. E. Crawford, S. Gulick, J. C. Hardy, A. Heinz, J. K. P. Lee, R. B. Moore et al. Improvements in the injection system of the Canadian Penning trap mass spectrometer Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 204 p. 487-491 2003