RANJAN ROY DANIEL (11 August 1923 - 27 March 2005)

Biog. Mem. Fell. INSA, N. Delhi 29 217-231 (2006)

RANJAN ROY DANIEL (1923 - 2005) Elected Fellow 1975

EARLY LIFE AND EDUCATION ANJAN ROY DANIEL was born in Nagercoil town in Kanyakumari District of RTamil Nadu State, as the third child in the family of five children, to Masilamani Arumanayagam Daniel and Theresa Chellammal Daniel on 11th August 1923. The rest of the four siblings were sisters. His father was a teacher of English at the Sethu Lekshrni Bai High School in the erstwhile Travencore State Government Service at Nagercoil; his mother was a housewife. His entire schooling from 1928 to 1939 was in the Scott Christian High School, Nagercoil. He inculcated a strong sense of self- discipline, a determination to pursue excellence and a spirit of nationahsm, which led him to the basic tenets of Gandhian Thought. He took active interest in games and outdoor life. His boyhood escapades included regular venturing into the verdant woods and purple mountains around the hometown, and picnicking in the plains. The ever roaring foamy beaches around had a special fascination for him and to quote "I had a carefree life in all respect in this small town". He joined the Scott Christian College in the hometown for the Intermediate Class. He developed a zest for sports and games and domed the College colors in Football, Basketball, and Volleyball. After passing the Intermediate Class of 1941, he went to Chennai and studied in the Loyola College, and obtained B.Sc. Degree from the University of Madras in 1943. His interest in games continued and he represented the Loyola College in Football. After completing the B-Sc. Degree, he worked as a Physics Demonstrator for a year in the Scot Christian College. Daniel told me that at this crucial juncture in his life, his classmate in Loyola College D Venkatesan wrote to him about the opportunity to study for M.Sc. Degree at the Banares Hindu University (BHU), where he had joined, and persuaded Roy to seek admission. His father encouraged him to go for higher studies in spite of financial difficulty. Thus, he went to Banares, took his M.Sc. Degree in Physics from BHU in 1946 with wireless as special subject and worked as a temporary lecturer for a year. He always mentioned with gratitude about his close friend Prof. Venkatesan, who was also a Cosmic Ray Physicist at the University of Calgary in Canada until his death, for influencing his career. At BHU he excelled in athletic also getting All Round Trophy presented by Jawaharlal Nehru Athletics in long jump, high jump and pole vault. He came to Mumbai in 1947 and joined the Tata Institute of Fundamental Research (TIFR) as a Research Assistant. After a year, he married Serena Biographical Memoirs Samuel, daughter of Dr G Manuel Samuel, who was a medical practitioner, and Annammal Samuel on 22nd December 1948. His first daughter Theresa Lalitha born on 2nd October 1949 was married to Dr Charles Rajkumar and is now settled in Pittsburgh. His son Samuel Revindran born on 2nd August 1955 had developed a farm in Nilgris mountain range and has married Alice Jasmine. His second daughter Anna Amutha born on 12th June 1958 was married to Andrew Thomas and is in Bangalore. The youngest daughter Sheila Rengitha born on 4th January 1963 was married to Manuel Clement and is settled in Chennai. Daniel lived in Mumbai over a major part of his life for nearly 41 years before he moved to Chennai, where he lived briefly for 7 years, and finally stayed in his hometown.

RESEARCH CAREER Roy Daniel's research career started when he joined Tata Institute of Fundamental Research (TIFR) in 1947. He immediately started his work on meson scattering and charge particle interactions in nuclear emulsions with Dr Homi J Bhabha. He went to the University of Bristol, United Kingdom in 1951 for higher studies sponsored by the Government of India. In continuation of the work in Mumbai, he carried out research in the HH Wills Physics Laboratory, headed by the Nobel Laureate CF Powell, using nuclear emulsions exposed to cosmic rays at high altitudes. He obtained Ph.D. Degree in April 1953 on "Production of heavy meson" under Prof. DH Perkins. He returned to TIFR in the same year and concentrated on the study of the production of heavy mesons in nuclear interactions at high energies using nuclear emulsions exposed to cosmic rays. Nuclear scattering of K- mesons was used to test the concept of the conservation of Strangeness in strong interactions. He was also involved in the study of the characteristics of high-energy interactions using accelerator particles. When the discovery of fundamental particles and their properties using cosmic rays were taken over by accelerator experiments with controlled beams in late fifties, the emulsion group at TIFR slowly turned their attention to primary cosmic ray studies. He did not lose any time in taking a leading role in this endeavour with the help of young scientists coming out of the Atomic Energy Training School. His interest in this area varied from high-energy interactions by cosmic rays well beyond the realm of accelerator energies to composition and energy spectra of primary nuclei. The advantage of the geographical location of India, over which cosmic ray particles of rigidity more than 10 GV/c could alone penetrate the earth magnetic field, was fully made use of by balloon borne emulsion detectors to study high energy primary cosmic rays. He measured fragmentation cross-sections of relativistic heavy nuclei and undertook a theoretical work on the transformation in the composition of galactic cosmic radiation due to their interaction with interstellar gas during propagation in the Galaxy. His participation in the inter collaboration to study nuclear interactions at 'jet' energies using ICEF emulsi Ranjan Roy Daniel exposed to cosmic rays, as the leader of the group working at TIFR, yielded interesting results.

(a) Primary Cosmic Ray Electrons The first attempt to measure the energy spectrum of high-energy cosmic ray electron component was started in 1961, using a stack of hyper-sensitized nuclear emulsions exposed over Hyderabad, but the emulsions could not be processed properly. Successful processing was achieved in the next attempt made in 1963, when an identical stack was oriented in the East-West direction during the balloon flight. Search for electrons was undertaken by him along with a few senior members of the emulsion group for a year, but yielded no results and his colleagues abandoned the search. He did not take this disappointment to heart, but decided to continue the search alone patiently with hope. On the day before I was to go on a vacation in April 1964, he described to me in detail the attempts made till then and asked me whether I had any new idea regarding this. This surprised me as I had joined TIFR in August 1961. The only experience I had was in a collaborative program between TIFR and the University of Bristol for very high energy interactions and gamma rays using electromagnetic cascades produced by them in a large emulsion-tungsten sandwiched stack, and was well versed with the first high speed computer in India at TIFR. I did not hesitate to suggest that it would be better to scan for a pair of minimum ionizing tracks between one radiation and one conversion lengths from the top of the stack, so that while tracing these tracks to their origin, the conversion point of gamma ray, one should find the primary electron track close by, if the pair is the cascade product of the electron. The next day he came to me with a number of questions, but I was ready with a set of calculated numbers of the photons radiated by an electron and those materialized between the suggested distances using electromagnetic theory. He was convinced only after a lengthy discussion and he told me that he would scan at one conversion length from the top of the emulsion. The search was fruitful and he got two electrons within a week and he wrote to me with excitement while I was on vacation that he would wait for me to return to continue the work with me. Thus started my close relationship with him in research. We carried out this experiment with the help of only one scanning assistant. Two important questions arose for the first time in emulsion technique regarding electrons. What is the probability of detecting an electron for the criteria adopted in the search and how it varies with energy? How to overcome the effect of spurious scattering while determining the energy using multiple coulomb scattering technique? These questions were answered from extensive theoretical calculations carried out bv me using- the electromagnetic theory. However, as a true experimentalis< he was convinced of the calculated results only after they were Biographical Memoirs verified using emulsion stacks exposed to electrons at accelerator energies. After this, he supported me in all the theoretical work I initiated and carried out in relation to astrophysical aspects of cosmic ray electrons, and we published many papers relating to cosmic ray confinement, relationship with the Universal Black Body Radiation, galactic radio background and magnetic field distributions and on galactic halo; KC Anand was also a partner in some of these. The electron era in the Institute came to an end in 1973, when it was found that we could not maintain the same momentum ahead of the rest of the world using the same technique. While I was at the NASA Johnson Space Flight Center as Senior Research Associate of the National Research Council from 1974 to 1977, he joined our group as NRC Senior Research Associate in 1976 for a year and we were involved in many publications. My close collaboration with him resulted three large review articles published together and I coauthored in about 40% of his published papers.

(b) Solar Neutrons, Cosmic Gamma Rays and Infrared Astronomy During the period when he was deeply involved in cosmic ray electrons, he also undertook a research programme to look for energetic neutrons from the Sun using nuclear emulsion. Emulsion detector being a passive one and in order to know the time of arrival of the incoming particles, electronic detectors were developed. As this instrument had the trigger to look for neutral particles, the same could also detect low energy gamma rays in the atmosphere. Useful upper limits on cosmic gamma ray flux were obtained. When he took the responsibility as the Dean of the Physics Faculty in 1970, his direct involvement in research became less due to his commitment to the administrative responsibility. But, seeing the end to cosmic ray research using nuclear emulsions, he decided to promote the idea envisaged by many in the cosmic ray group to look into the relatively unexplored area of Far- Infrared Astronomy. It was a Herculean task, as cryogenic technology at liquid helium temperatures was not available in this country and technique to maintain a stable platform to keep a large telescope pointing to directions as preplanned needed very careful innovations. Further, it was not easy to get enough foreign exchange to import the basic components and detector elements to leap forward in this area of research. It took a decade for a few dedicated young scientists to breathe a sigh of relief in getting the infrared telescope operational, in spite of the frustration of not being able to publish papers over this long period. Unfortunately, the telescope was lost during the first flight shattering their hope of doing infrared astronomy, after putting so much of hard work. Further, pouring oil in this burning fire, some members of the Space Physics Group suggested to terminate this infrared project. But, this disappointed group was determined to rebuild a better telescope in a shorter period of time as they had already paved a path through a difficult terrain to build such a complex instrument. Daniel comforted them at the time of the the telescope, gave support and stood by them. He convinced the Institut Ranjan Roy Daniel determination and the capability of his group members and obtained the required fund to make a better telescope than the one previously flown. They certainly achieved this and with this new telescope, not only a large number of papers were published, but also requests came in from technically advanced countries to use this infrared telescope platform with proposals to transfer detector technologies and collaborate with the group members.

A HUMBLE MAN One special quality in Roy Daniel, which stood out all through his life, is his extraordinary humble behaviour. Because of this, anyone who had problems in the work place would not hesitate to meet him and tell their woes. His patient listening, his concern and the comforting words helped them. At any given time many scanners used to work for a project under him and when he needed help from them, his approach was totally different from others. Instead of asking the scanner directly, he would look for the research student with whom the scanner worked, described his needs and requested him or her to lend a scanner to help him. His success of getting support and commitment for large collaborative projects from people who were hard to approach was due to this quality, because it was difficult for any one to hurt his feelings when he approached them in a humble manner. I attended a lecture series on cosmology by Prof. JV Narlikar at the Physical Research Laboratory in Ahmedabad in January 1966. Soon after my return to TIFR, I realized that the black body radiation, which was on the headlines, has profound effect in modifying the energy spectrum of cosmic ray electrons depending on where they spent their lifetime. After analyzing our electron data to obtain the energy spectrum and tomparing with that expected using the black body radiation, I wrote a paper on 'Cosmic electrons above 10 GeV and the universal black body radiation at 3oK' to be published in Physical Review Letters (PRL). I gave it to Daniel to go through and he told me after a few words of encouragement for my effort, that he earned a good reputation as an experimentalist, which he would not risk by venturing in remote areas of cosmology and persuaded me to concentrate on the experiment. I approached him over the next few months, every time with a new corrected draft. He finally looked at it carefully, but modified the entire paper as an experimental one and included my write up only as part of the implication of results. He kept that on my table along with my last draft. I was very upset and I crushed both the papers, threw them in the waste paper basket and went to the hostel. When he came to look for me he found that my table was very clean. He removed the crushed papers, straightened them and kept back his draft on my table with a note to see him and took the other one with him. Next day when I came to my room, I saw his note, but was afraid to see him thinking that I had hurt his feelings. He read my draft many times in the office and at home, and realized its importance. came to the office, he called me to his room and apologized for not lookin Biogmyhical Memoirs other corrected versions. He only requested me to include the e+ / e- ratio we obtained, keeping the rest of the paper as I had written. He explained to me that, though this aspect of our result had no relevance to the paper, it was essential to be truthful to all the results we got from our experiment. I agreed to it and we spent a few hours going through the paper in detail correcting the language for a better presentation, which he was very good at. The paper was submitted for publication in PRL in September 1966, received on 27th September and published on 24" October; neither did we receive the acknowledgement nor the proof. One can see how he set aside my frustration over many months simply by his humble behaviour that too before a person, fourteen years junior to him.

ACTIVITIES BEYOND TATA INSTITUTE OF FUNDAMENTAL RESEARCH By this time Daniel enlarged his interest to national projects and had a very successful career as a major scientific figure in India. While most of the projects were initiated during his tenure at TIFR, some of them took place only after he retired and went to Chennai. As the Chairman of the Advisory Committee for Space Science of ISRO, he provided the leadership for a number of projects. The Indian Middle Atmosphere Programme using 30 stratospheric balloons, 120 meteorological rockets and 20 larger rockets, involved nearly 250 scientists from about 10 National laboratories and 15 Universities. Multi-departmental funding was required to undertake this project from ISRO, DST, CSIR, DAE, UGC and IMD. This was not easy for an individual to convince so many institutions to come together and undertake this project. I believe that his vision to tackle the complex middle atmospheric science programme effectively, by the joint effort of experts from different areas in this field, was appreciated by these institutions and his humble approach was mainly responsible for the commitment made by the individuals. At the same time he initiated the setting up of the Mesosphere, Stratosphere and Troposphere (MST) radar near Tirupathi, which could probe the atmosphere over a wide range from 5 to 100 km. This project involved a different combination of Government Departments namely ISRO, DOE, DST, CSIR and DRDO. He initiated the manufacture of small three-inch telescopes for schools to promote education and training to students in Astronomy. This telescope was designed by Indian Institute of Science and manufactured by CSIO-CSIR at Chandigarh, and this project was funded by ISRO. These telescopes were either sold or gifted to schools, colleges and individuals. As Chairman of the National Committee for IGBP, he initiated, organized and coordinated with foresight an Indian long-term programme from 1994. This programme related to the Study of Global Change for the International Geosphere Biosphere Programme, which was launched by ICSU. This project was supported by various Government Depa and agencies, such as, DOS, DST, DOEn, INSA, CSIR, and UGC. To achieve Ranjan Roy Daniel in such multi-agency projects was not an easy task, but required excellent judgment in choosing the right project, diplomatic skills and commitment. He also persuaded and encouraged scientists to carry out scientific experiments using Indian satellites to promote a sense of National Achievements in spite of the low success for such initial ventures, which may not lead to exciting results.

ROY AND COSPAR When the Committee on Space Research (COSPAR) was established by ICSU at the close of International Geophysical Year 1957-58, COSPAR Charter was drafted. This Charter reflected the supremacy of USA-USSR in space'. US National Academy of Sciences and the erstwhile USSR Academy of Sciences jointly nominate the President of the COSPAR Bureau, each one of the above Academies nominates one Vice- President and two members. The rest of the contributing National Members of COSPAR had no role to play in constituting the Bureau. In 1982, when Roy attended the COSPAR Plenary Session in Ottawa, he decided to bring to the notice of the COSPAR Council this unusual structure. To quote him, "Being much surprised by this, I pointed it out in the business meeting of the COSPAR Council, which consisted of the President, representatives COSPAR National Members and concerned representatives of the International Scientific Unions of ICSU. To my great surprise, there was a long silence in the room. Sir Harrie Massey, the distinguished UK representative and a founder member of COSPAR, stood up and cryptically remarked that he shared the Indian concern and suggested the matter for further consideration. But it is clear from what followed that the Bureau acted quickly. At the Graz Plenary in 1984, under the Presidency of Prof. C de-Jager, the first revision was approved in which Membership was increased from four to six, with the additional members to be selected in a democratic manner. Prof. K Hirao of Japan and I were selected as the two additional members of the Bureau. A second revision of the Charter was adopted at the Washington Plenary in 1992, under the Presidency of Prof. WI Oxford, in which all members of the Bureau are to be selected through democratic procedure. A very happy ending!" Soon after he became a member of the COSPAR Bureau, he launched his idea of promoting Space Science in Developing Countries. The then defunct COSPAR Panel on Space Research in Developing Countries was revived and revitalized over a period of next 8 years. As Chairman of this Panel and later as Scientific Secretary of the ICSU Committee on Science and Technology in Developing Countries of Asia, he helped in promoting international cooperation by introducing new modes of support for scientists and organizing excellent symposia. His efforts to find funds and wisely use them to support participation of developing country scientists in international conferences, many of them organized in conjunction with COSPAR and/or United Nations, have been widely appreciated and testify his excellent judgment of scientific needs as well as his diplomatic skills. Biographical Memoirs AFTER TIFR After his retirement from the Tata Institute of Fundamental Research as a Senior Professor in August 1988, he became the Scientific Secretary of the Committee on Science and Technology in Developing Countries (COSTED) from 1988 to 1995. This was one of the busy periods in his professional life. Nation wide projects and international commitments he initiated, while he was at TIFR and described earlier in Sections 4 and 5 were continued and completed successfully. He reorganized the International Secretariat of the COSTED in Chennai and started new regional and international programmes. During this period, he was also the Emeritus Scientist of CSIR. Regional centres in Africa, South America, Middle East and Asia were started or strengthened and National Membershp was enlarged. He established relations with United Nations and International Organizations, a new constitution was framed and a new secretariat building was constructed during his tenure. To increase the awareness of developing countries to participate in international scientific programmes, he took the effort to circulate a Hand Book on Activities of ICSU Bodies towards developing countries. A special booklet on why developing countries should participate in ICSU was written and circulated and he facilitated their participation in IGBP. He also edited an innovative book on the concept of Biotechnology written by a team of international experts, which was published by Orient Longman Ltd. in 1996.

AWARDS AND RECOGNITIONS Daniel was awarded Sir CV Raman Award for Experimental Research in 1974 for his outstanding contributions in the study of cosmic rays, particularly High Energy Electrons. The INSA-Vainu Bappu Memorial Award was presented to him in 1992 for his pioneering contributions in high-energy cosmic ray electrons and his leadership in balloon borne far infrared astronomy. In the same year Padmabushan was conferred on him by the Government of India for his contribution to the welfare of the Nation through Science and Technology. The COSPAR International Cooperation Medal was awarded to him in 1994 for his outstanding contributions in promoting international cooperation towards the development of research in Developing Countries. He was a Fellow of the Indian Academy of Sciences; Jndian National Science Academy; National Academy of Sciences, Allahabad; Maharashtra Academy of Sciences; Third World Academy of Sciences and Corresponding Member of International Academy of Astronautics. He served as a member of the council of both IAS and INSA, and served as Vice President of the latter. He was the founder member of Indian Physics Association and Astronomical Society of India. He was the founder Chairman of the Bombay Association for Science Education. He also served in various capacities as Member/Chairman/Convener in National Committees and Managing Councils. Ranjan Roy Daniel AFTER RETIREMENT Health problems came in the way of his dedication to science and he retired from active service in 1995 and came to Nagercoil. After he returned to his native town, he was involved in promoting Science and Technology education in the district level by giving lectures. He was writing newspaper articles on global issues relating to the impact of human action on the environment and their implication for the 21st century. He edited a book on Concept in Space Science written by experts in this field with the limited facility in the hometown. Tlus work was sponsored and funded by ISRO and co-sponsored by COSPAR, TWAS and the UN Office for Outer Space Affairs, and was published by Universities Press (India) Pvt. Ltd. in 2002. His health slowly failed over a period of time due to the complications connected with prostate cancer treatment and was admitted to the hospital on 27th November 2004 and breathed his last on the Easter Day, the 27th March 2005. Thus, the country lost a dedicated and hard working scientist, Ranjan Roy Daniel. Many would remember his successful scientific career at the Tata Institute of Fundamental Research and the tiresome work of initiating and managing many scientific projects in the country, bringing scientists working in different areas and from different Government Departments, to work together to achieve common science goals. He brought credit to the Nation from his involvements in International Organizations by promoting space science in Developing Countries. He is survived by his wife Padmini, all his children with their spouses and eight grand children. I acknowledge the useful information provided by his family members, the Indian Academy of Sciences and the Indian National Science Academy and some of my colleagues at TIFR. I also thank SL Winston for going through the manuscript. S ALFRED STEPHENS 32, Vani Cooperative Housing Society Sector 6, CBD Belapur Navi Mumbai-400 614 E-mail: [email protected]

BIBLIOGRAPHY (With BHABHA HJ) Meson scattering (With nuclear excitation) Nature 161 883-888 (With Bhabha HJ et al) Stars and single tracks in nuclear plates Proc Ind Acad Sci 31 130-139

(With PERKINS DH et al) Nuclear interactions of great energy - Part I Evidence for the creation of heavy mesons Phil Mag 43 753 (With PERKINS DH) Production of heavy mesons by protons of energy between 2 and 3000 GeV Proc Royal Soc 221 531-366 (With YASH PAL et al) Investigation of gray tracks of particles ejected from energetic nuclear explosions Nuovo Cim XI1 Supp12 231 1954 (With YASH PAL) An abnormal tau-meson decay Proc Ind Acad Sci 40 114-118 Biographical Memoirs (With PETERS B et al) On the construction of large nuclear emulsion block detector Proc Id Acad Sci 40 151-157 (With LAL D) Nuclear interaction of K-mesons Proc Ind Acad Sci 41 15-24 (With GEORGE EC and PETERS B) Range-energy relation in nuclear emulsion Proc Ind Acad Sci 41 45-48 (With APPARAO MVK and NEELAKANTAN KA) Nuclear disintegrations produced in nuclear emulsion by alpha particles of great energy Proc Ind Acad Sci 43 181-201 (With PETERS B et al) Observations of K-mesons and Hyperons Nuovo Cirn 4 Series X 474478 (With PETERS B et al) The abundance of light nuclei in the primary cosmic radiation Phys Rev 110 751-765 (With MENON MGK and SREEKANTAN BV) International conference on cosmic raysCurr Sci 28 389-391 (With MALHOTRA PK et al) Some characteristics of inelastic proton-nucleon collisions produced by protons of energy 6 2 BeV in nuclear emulsions Nuovo Cirn 16 1-25 (With LAVAKARE PJ and ADITYA PK) A method of detecting the possible existence of high energy deuterons in the primary cosmic radiation Nuovo Cirn 17 837-844 (With BADHWAR GD and WJAYALAKSHIMI B) The production of radio isotopes in collisions of cosmic ray nuclei (With hydrogen in space and the effect of their decay on the composition of the radiation observed near the earth Prog Theo Phys Japan 26 60 -623 (With DURGAPRASAD N) The composition of heavy nuclei of the primary cosmic radiation J Phys Soc Japan 17 AIII 15 (With DURGAPRASAD N) The chemical composition of the primary cosmic radiation above the earth's atmosphere Nuovo Cim 23 82-111 (With BADHWAR GD) Some remarks concerning the energy dependence of the intensities of nuclei of Helium3 Lithium Beryllium and Boron in the galactic cosmic radiation Prog Theo Phys Japan 30 615-626 (With DURGAPRASAD N et al) The interaction mean free paths of nucleons and alpha particles of high energes in emulsion Suppl Nuovo Cim 11163-1168 (With DURGAPRASAD N et al) Identification of the persisting baryon and its application in an analysis of nuclear interactions at high energies Suppl Nuovo Cim 1 1169-1187 (With THREE OTHERS TIFR) International collaboration in emulsion flights Joint paper publication from about 20 laboratories Suppl Nuovo Cirn 11039-1091 (With SREENIVASAN N) The energy spectrum of primary cosmic ray protons of energy 4-16 GeV from simultaneous flights from Texas USA and Hyderabad India Nuovo Cirn 35 391-397 (With STEPHENS SA) Electron component of the primary cosmic radiation at energies > 15 GeV Phys Rev Letters 15 769-772 1966 (With STEPHENS SA) Directional variations of geomagnetic cut-off rigidity around Hyderabad India Proc Indian Acad Sci 63 Sec A 275-283 (With DURGAPRASAD N) The age of cosmic ray nuclei and their propagation in Theo Phys Japan 35 36-43 Ranjan Roy Daniel 1966 (With APPARAO MVK et al) Evidence for the possible emission of high energy neutrons from the sun J Geophys Res 71 1781-1785 (With STEPHENS SA) Cosmic electrons above 10 GeV and the universal black body radiation at 30K Phys Rev Letters 17 935-939 1967 (With GEORGE JOSEPH et al) High energy neutrons from the sun Nature 213 21-23 (With STEPHENS SA) Recent observations of cosmic electrons and their consequences on different cosmic ray models and related astrophysical quantities Proc Indian Acad Sci 65 Sec A 319-339 (With ANAND KC and STEPHENS SA) Radio emitting electrons in the Galaxy and the solar modulation of cosmic rays Nature 217 25-27 (With ANAND KC and STEPHENS SA) High energy gamma rays of cosmic origin Canad J Phys 46 984-987 (With STEPHENS SA et al) Rigidity spectrum of cosmic ray helium nuclei > 12GV Canad J Phys 46 S652-S653 (With APPARAO MVK et al) Gamma rays and high energy neutrons in the atmosphere Canad J Phys 46 S1030-S1033 (With ANAND KC and STEPHENS SA) Cosmic ray electron spectrum above 50 BeV and its implications for cosmic ray confinement Phys Rev Letters 20 764-768 (With STEPHENS SA et al) Rigidity spectrum of cosmic ray helium nuclei Proc Ind Acad Sci 67 Sec A 138-154 (With ANAND KC and STEPHENS SA) Electrons magnetic fields and background radio emission in the Galaxy Proc Ind Acad Sci 67 Sec A 267-282 (With ANAND KC and STEPHENS SA) On the existence of the galactic radio halo Proc Ind Acad Sci 68 Sec A 219-227 (With ANAND KC and STEPHENS SA) Cross-section for the *He 3H) stripping reactions on Fe A1 C and glass targets at an energy of 120 MeV Solar Phys 8 152-154 (With ANAND KC and STEPHENS SA) Cosmic ray electron spectrum above 200 GeV Nature 224 1290-1291 (With GOKHALE GS et al) Search for energetic neutrons emitted during solar flares Solar Phys 10 465-471 (With STEPHENS SA) Cosmic electrons and related astrophysics Sp Sci Rev 10 599-671 (With ANAND KC and STEPHENS SA) The cosmic ray electron spectrum at energies >I00 GeV Acta Phys Acad Sci Hung 29 Suppl 1 229-234 (With ANAND KC and STEPHENS SA) The charge composition of the primary cosmic ray electrons between 10 and 30 GeV Acta Phys Acad Sci Hung 29 Suppl 1 235-239 (With STEPHENS SA) The confinement of cosmic ray electrons Acta Phys Acad Sci Hung 29 Suppl 1531-539 (With GOKHALE GS et al) Energetic neutrons and gamma rays at balloon altitudes over equatorial latitude Acta Phys Acad Sci Hung 29 Suppl2 697-702 Biographical Memoirs (With GOKHALE GS et al) An improved estimate of solar neutron flux measured in an earlier experiment J Geophys Res 76 3152-3153 (With THREE OTHERS TIFR) A TIFR-CERN-Cracow collaboration The angular distribution of secondary particles produced in the interacting storage rings at energy equivalent to 1500 GeV Phys Lett 36B 611-614 (With DAMLE SV et al) Cosmic flux of low energy gamma rays Astrophys Sp Sci 14 473-479 (With DAMLE SV et al) Extragalactic origin of low energy gamma rays Nature 235 319-320 (With GEORGE JOSEPH and LAVAKARE PJ) The diffuse cosmic gamma rays observed at an equatorial balloon altitude Astrophys Sp Sci 18 462-467 (With ANAND KC and STEPHENS SA) Atmospheric gamma rays in the energy region 40- 1000 GeV Pramana 11-1 1

(With GANGULI SN et al) Study of pp + y + anything at the ISR at E,, = 44 4 GeV and its implications for no production and multiplicity Nucl Phys B63 45-53 (With STEPHENS SA) Cosmic ray produced electrons and gamma rays in the atmosphere Rev Geophys Sp Phys 12 233-258 (With Stephens SA) Propagation of cosmic rays in the Galaxy Sp Sci Rev 17 45-158 (With ANAND KC and STEPHENS SA) The energy spectrum of cosmic ray electrons between 10 and 1000 GeV Astrophys Sp Sci 36 169-175 (With LAVAKARE PJ) The diffuse cosmic gamma rays Pramana 5 107-117 (With DAMLE SV and LAVAKARE PJ) Energetic neutrons and gamma rays measured on Aryabhata Satellite Pramana 7 355-368 (With BADHWAR GD and STEPHENS SA) Cosmic ray electrons and galactic radio emission - a conflict? Nature 265 424-426 (With APPARAO MVK) The electron-proton abundance ratio in cosmic rays Astrophys Sp Sci 46 225-237 (With BADHWAR GD and STEPHENS SA) Radio emitting electrons and cosmic ray confinement Astrophys Sp Sci 49 133-143 (With STEPHENS SA et al) The cosmic ray antiproton flux An upper limit near that predicted for secondary production Astrophys J Letters 217 L135-L138 (With STEPHENS SA et al) Relative Abundance of Antiprotons and Antihelium in the Primary Cosmic Radiation Nature 274 137-139 (With APPARAO MVK et al) An experiment to detect energetic neutrons and gamma rays from the sun Proc Ind Acad Sci C1313 (With STEPHENS SA et al) Evidence for the Existence of Cosmic Ray Antiprotons Phys Rev Letters 43 1196-1199 (With STEPHENS SA) Antimatter in Cosmic Rays Bull Astr Soc lndia 8 115-122 Charm production in 400 GeV/c pioton-emulsion interactions Bombay - Chandigarh - collaboration Nucl Phys I3199 424-440 (With GHOSH SK et al) Far-infrared brightness temperature of Saturn's disk and r 49 205-212 Ranjan Roy Daniel

1983 Space sciences in Developing Countries - the Indian experience Adv Sp Res 3 35 (With VERMA RP et al) Infrared observations of Beta Cephei and Delta Scuti stars Astrophys Sp Sci 92 173-176 (With VERMA RP et al) Near infrared photometry of some RS CVn systems and candidates Astrophys Sp Sci 97 161-169 (With STEPHENS SA et al) A Measurement of the Absolute Flux of Cosmic Ray Electrons Astrophys J 287 622-632 (With GHOSH SK et al) JHK infrared photometry of 'Unidentified' EIC-1 sources Mon Not Royal Astr Soc 206 611-624 (With GHOSH SK et al) A 750 mm Balloon borne telescope for far-infrared astronomical observations J Phys E 17 160-168 (With GHOSH SK et al) Far-infrared (100-200ym) photometry of HI1 regions (With 1 m balloon borne telescope in Light on Dark Matter (Reidel Pub Co) Ed FP Israel 305-306 (With GHOSH SK et al) Far-infrared (100-300ym) observations of the Carina nebula Astrophys J 330 928-926 (With GHOSH SK et al) A study of the W-31 star forming region Astrophys J 347 338-348 (With GHOSH SK et al) Far-infrared 120-300 micron observations of southern HI1 regions Astrophys J Suppl69 233-239 (With GHOSH SK et al) Far-infrared observations of G351 6-1/G 351 7-1 2 region Astrophys J 353 564-569